## Search found 100 matches

Sun Mar 14, 2021 11:38 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Standard Cell Potential
Replies: 3
Views: 20

### Standard Cell Potential

Hey guys!
I was wondering if anyone could help me understand the relationship between standard cell potential and equilibrium constant of a reaction?
Thank you!
Sun Mar 14, 2021 11:34 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Entropy Factors
Replies: 3
Views: 12

### Entropy Factors

Hey guys! One of the objectives on outline 5 states: -Explain how temperature, volume, and state of matter affect the entropy of a substance. I know how temperature and volume influence entropy, however, I was wondering if anyone could help me out with how state of matter influences entropy? Thank y...
Sun Mar 14, 2021 11:30 pm
Forum: Phase Changes & Related Calculations
Topic: Steam v. Water
Replies: 4
Views: 24

### Steam v. Water

Hey guys! One of the objectives on outline 3 says: -Explain why steam at 100 C causes a worse burn than boiling water at 100 C. I was wondering if someone could answer this objective. I know it has to do with the water changing states, but I am not sure if the release of heat is because of the state...
Sun Mar 14, 2021 11:24 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: strong vs weak acid pH level
Replies: 2
Views: 13

### strong vs weak acid pH level

Hey guys!
I was having trouble answering one of the objectives from outline 2 and I was wondering if anyone could help out:
-Explain why solutions of weak acids have higher pH values than solutions of strong acids at the same concentration.
Thank you!
Sun Mar 14, 2021 11:16 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Reaction Quotient Predictions
Replies: 6
Views: 20

### Reaction Quotient Predictions

Hey guys!
I was wondering if someone could explain how we can use Q to predict the direction of a nonequilibrium reaction?
Thank you!
Sun Mar 07, 2021 11:48 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Textbook Problem 6.51
Replies: 2
Views: 12

### Textbook Problem 6.51

A galvanic cell functions only when the electrical circuit is complete. In the external circuit, the current is carried by the flow of electrons through a metal wire. Explain how the current is carried through the cell itself. Hey guys! I was wondering if someone could explain the answer to this pro...
Sun Mar 07, 2021 11:44 pm
Forum: *Organic Reaction Mechanisms in General
Topic: Textbook Problem 6.43
Replies: 3
Views: 29

### Textbook Problem 6.43

Indicate for each of the following statements whether it applies to Ecell°, to Ecell, to both, or to neither: (a) decreases as the cell reaction progresses; (b) changes with temperature; (c) doubles when the coefficients of the equation are doubled; (d) can be calculated from K; (e) is a measure of ...
Sun Mar 07, 2021 11:36 pm
Forum: *Free Energy of Activation vs Activation Energy
Topic: Activation Energy and Catalysts
Replies: 5
Views: 48

### Activation Energy and Catalysts

Hey guys! I was wondering if someone could explain the relationship between the addition of a catalyst and the activation energy of a reverse reaction? Thank you!
Sun Mar 07, 2021 11:33 pm
Forum: *Free Energy of Activation vs Activation Energy
Topic: Sapling #17 Wk.9-10
Replies: 6
Views: 30

### Sapling #17 Wk.9-10

A certain reaction has an enthalpy of ΔH=49 kJ and an activation energy of Ea=81 kJ. What is the activation energy of the reverse reaction? Hey guys! I was wondering if anyone could explain the different steps in terms of solving for the regular activation energy and solving for the activation energ...
Sun Mar 07, 2021 11:28 pm
Forum: *Free Energy of Activation vs Activation Energy
Topic: Sapling #15 Wk.9-10
Replies: 3
Views: 142

### Sapling #15 Wk.9-10

Calculate the activation energy, Ea , in kilojoules per mole for a reaction at 69.0 ∘C that has a rate constant of 0.298 s−1 and a frequency factor of 8.07×1011 s−1 .
Hey guys! I was wondering if anyone could explain what formula is necessary to solve this problem?
Thank you!
Sun Feb 28, 2021 11:49 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: 6N.17 Textbook Question
Replies: 3
Views: 13

### 6N.17 Textbook Question

Consider the cell Ag(s)|Ag+(aq, 5.0 mmol⋅L−1)||Ag+(aq, 0.15 mol⋅L−1)|Ag(s). Can this cell do work? If so, what is the maximum work that it can perform (per mole of Ag)?
Can anyone explain how to calculate the maximum work per mole of Ag?
Thank you!
Sun Feb 28, 2021 11:47 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Textbook Problem 6N.9
Replies: 1
Views: 6

### Textbook Problem 6N.9

A tin electrode in 0.015 M Sn(NO3)2(aq) is connected to a hydrogen electrode in which the pressure of H2 is 1.0 bar. If the cell potential is 0.061 V at 25 °C, what is the pH of the electrolyte at the hydrogen electrode? Can anyone explain which formula we are supposed to use for this particular pro...
Sun Feb 28, 2021 11:44 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Textbook Problem 6M.7
Replies: 1
Views: 14

### Textbook Problem 6M.7

Arrange the following metals in order of increasing strength as reducing agents for species in aqueous solution: (a) Cu, Zn, Cr, Fe; (b) Li, Na, K, Mg; (c) U, V, Ti, Al; (d) Ni, Sn, Au, Ag.
Can anyone explain any rules or guidelines in regards to the strength of reducing agents?
Thank you!
Sun Feb 28, 2021 11:42 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Textbook Problem 6l.9 [ENDORSED]
Replies: 3
Views: 62

### Textbook Problem 6l.9[ENDORSED]

(a) Write balanced half-reactions for the redox reaction of an acidified solution of potassium permanganate and iron(II) chloride. (b) Write the balanced equation for the cell reaction and devise a galvanic cell to study the reaction (write its cell diagram). Can anyone explain how to write out the ...
Sun Feb 28, 2021 11:40 pm
Forum: Balancing Redox Reactions
Topic: Textbook Problem 6K.1
Replies: 2
Views: 16

### Textbook Problem 6K.1

The following redox reaction is used in acidic solution in the Breathalyzer test to determine the level of alcohol in blood: H+(aq)+Cr2O72−(aq)+C2H5OH(aq)→Cr3+(aq)+C2H4O(aq)+H2O(l) Identify the elements undergoing oxidation or reduction and indicate their initial and final oxidation numbers. (b) Wri...
Sun Feb 21, 2021 6:48 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: C vs Cs/Cm
Replies: 8
Views: 46

### C vs Cs/Cm

When a copper rod is heated from 25 °C to 75 °C, roughly 487.5 J of heat is consumed. If the rod weights 25 g, what is the specific heat capacity of copper? What is the molar heat capacity? Take the molar mass of copper to be 63.546 g mol-1. Hey guys! I was wondering if anyone could explain the diff...
Sun Feb 21, 2021 6:44 pm
Forum: Calculating Work of Expansion
Topic: Calculating W
Replies: 4
Views: 26

### Calculating W

The entropy associated with a solid in which each molecule can be found in W distinct orientations is 4.5 x 10-22 J·K-1 at 0 K. If the sample is composed by 30 molecules, what is the value of W? Hey guys! I was wondering if anyone could explain how to set up the equation or formula that we need for ...
Sun Feb 21, 2021 6:40 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Solving for changes in entropy
Replies: 1
Views: 29

### Solving for changes in entropy

A cubic container is divided into two equal sections by a metallic partition. One of the container's halves is initially empty. The other halve has 45 moles of argon gas at 298 K. The partition is eventually removed and the gas can freely move throughout the whole container. What will be the change ...
Sun Feb 21, 2021 6:26 pm
Forum: Third Law of Thermodynamics (For a Unique Ground State (W=1): S -> 0 as T -> 0) and Calculations Using Boltzmann Equation for Entropy
Topic: Calculating Microstates and Residual Entropy
Replies: 3
Views: 40

### Calculating Microstates and Residual Entropy

How many microstates are available to a regular dice? What would be the residual entropy associated with a collection of 3 dice? Hey guys! This was a question that I had on my discussion section practice quiz. I was wondering what steps we would take to solve this problem and what equations/formulas...
Sun Feb 21, 2021 6:09 pm
Forum: Ideal Gases
Topic: Calculating temperature change
Replies: 4
Views: 27

### Calculating temperature change

Under constant pressure conditions the expansion of 0.17 moles, causes an ideal gas to experience a 3.4 atm·L increase in its internal energy. If the system performed 2.26 atm·L of work, what was the temperature change of the gas? Hey guys! This problem was from my discussion section practice quiz. ...
Sun Feb 14, 2021 11:26 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Textbook Problem 4C.1
Replies: 2
Views: 6

### Textbook Problem 4C.1

Which gaseous compound do you expect to have the higher molar heat capacity, NO or NO2? Why?
Hey guys! I was wondering what the approach to these kinds of problems would be? Do we have to draw out the structure of the molecules mentioned in the problem?
Thank you!
Sun Feb 14, 2021 11:23 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Textbook Problem 4B1
Replies: 1
Views: 9

### Textbook Problem 4B1

A gas sample in a cylinder is supplied with 524 kJ of energy as heat. At the same time, a piston compresses the gas, doing 340 kJ of work. What is the change in internal energy of the gas during this process? Hey guys! I was wondering if there is a specific formula that pertains to calculating the c...
Sun Feb 14, 2021 11:19 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Textbook Problem 4A.9
Replies: 3
Views: 34

### Textbook Problem 4A.9

A piece of copper of mass 20.0 g at 100.0°C is placed in a vessel of negligible heat capacity but containing 50.7 g of water at 22.0°C. Calculate the final temperature of the water. Assume that no energy is lost to the surroundings. Hey guys! I was wondering if anyone could explain the steps or form...
Sun Feb 14, 2021 11:15 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Textbook Problem 4A.5
Replies: 2
Views: 10

### Textbook Problem 4A.5

A piston confines 0.200mol Ne(g) in 1.20 L at 25 °C. Two experiments are performed. (a) The gas is allowed to expand through an additional 1.20 L against a constant pressure of 1.00 atm. (b) The gas is allowed to expand reversibly and isothermally to the same final volume. Which process does more wo...
Sun Feb 14, 2021 11:11 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Textbook Problem 4A.1
Replies: 3
Views: 13

### Textbook Problem 4A.1

Identify the following systems as open, closed, or isolated: (a) coffee in a very-high-quality thermos bottle; (b) coolant in a refrigerator coil; (c) a bomb calorimeter in which benzene is burned; (d) gasoline burning in an automobile engine; (e) mercury in a thermometer; (f) a living plant. Hey gu...
Sun Feb 07, 2021 11:57 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Textbook Problem 4I.1
Replies: 1
Views: 22

### Textbook Problem 4I.1

4I.1 What is the total entropy change accompanying a process in which 40.0 kJ of energy is transferred as heat from a large reservoir at 800. K to one at 200. K?
Can someone please explain the setup that I would need for this problem?
Thank you!
Sun Feb 07, 2021 11:56 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Textbook Problem 4H.3
Replies: 1
Views: 31

### Textbook Problem 4H.3

4H.3 List the following substances in order of increasing molar entropy at 298 K and 1 bar: H2O(l), H2O(g), H2O(s), C(s, diamond). Explain your reasoning.
Can someone please explain what formula/relationship we are supposed to apply to this problem?
Thank you!
Sun Feb 07, 2021 11:54 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Textbook Problem 4G.3
Replies: 1
Views: 12

### Textbook Problem 4G.3

4G.3 Which would you expect to have a higher molar entropy at T=0, single crystals of BF3 or of COF2? Why?
Can anyone explain the relationship between entropy and structure?
Thank you!
Sun Feb 07, 2021 11:51 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Textbook Problem 4F.17
Replies: 1
Views: 25

### Textbook Problem 4F.17

4F.17 Calculate the standard entropy of vaporization of water at 85 °C, given that its standard entropy of vaporization at 100. °C is 109.0J⋅K−1⋅mol−1 and the molar heat capacities at constant pressure of liquid water and water vapor are 75.3JK−1⋅mol−1 and 33.6J⋅K−1⋅mol−1, respectively, in this rang...
Sun Feb 07, 2021 11:49 pm
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: Textbook Problem 4F.5
Replies: 1
Views: 13

### Textbook Problem 4F.5

4F.5 Calculate the entropy change associated with the isothermal expansion of 5.25 mol of ideal gas atoms from 24.252 L to 34.058 L.
Hey guys I was wondering if anyone could explain the general guidelines on how to solve this problem?
Thank you!
Sun Jan 31, 2021 11:38 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: 4D.15 Textbook Question
Replies: 4
Views: 19

### 4D.15 Textbook Question

Determine the reaction enthalpy for the hydrogenation of ethyne to ethane, C2H2(g)+2H2(g)→C2H6(g), from the following data: ΔHc°(C2H2,g)=−1300.kJ⋅mol−1, ΔHc°(C2H6,g)=−1560.kJ⋅mol−1, ΔHc°(H2,g)=−286kJ⋅mol−1 . Hey guys! I had a question regarding how we would setup the equations in this problem? Would...
Sun Jan 31, 2021 11:33 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: 6E.1 Textbook Question
Replies: 3
Views: 34

### 6E.1 Textbook Question

Calculate the pH of 0.15 M H2SO4(aq) at 25 °C.
Hey guys!
I was wondering if anyone could walk me through the steps of this problem?
Thank you!
Sun Jan 31, 2021 11:08 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: 6D.9 Textbook Question
Replies: 2
Views: 8

### 6D.9 Textbook Question

The percentage deprotonation of benzoic acid in a 0.110 M solution is 2.4%. What is the pH of the solution and the Ka of benzoic acid? Hey guys! Can someone please explain how to calculate the Ka in this problem? Are we supposed to have the benzoic acid formula memorized already, or are we allowed t...
Sun Jan 31, 2021 11:04 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: 6D.5 Textbook Question
Replies: 1
Views: 24

### 6D.5 Textbook Question

Calculate the pH, pOH, and percentage protonation of solute in each of the following aqueous solutions: (a) 0.057 M NH3(aq); (b) 0.162 M NH2OH(aq); (c) 0.35 M (CH3)3N(aq); (d) 0.0073 M codeine, given that the pKa of its conjugate acid is 8.21. Hey guys! I was wondering if someone could explain part ...
Sun Jan 31, 2021 10:57 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: 6B.11 Textbook Question
Replies: 1
Views: 11

### 6B.11 Textbook Question

A student added solid Na2O to a volumetric flask of volume 200.0 mL, which was then filled with water, resulting in 200.0 mL of NaOH solution. Then 5.00 mL of the solution was transferred to another volumetric flask and diluted to 500.0 mL. The pH of the diluted solution is 13.25. (a) What is the mo...
Sun Jan 24, 2021 9:35 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Textbook Question 6B.5
Replies: 3
Views: 21

### Textbook Question 6B.5

Calculate the pH and pOH of each of the following aqueous solutions of a strong acid or base: (a) 0.0146 M HNO3(aq); (b) 0.11 M HCl(aq); (c)0.0092 M Ba(OH)2(aq);(d) 2.00 mL of 0.175MKOH(aq) after dilution to 0.500 L; (e) 13.6 mg of NaOH dissolved in 0.350 L of solution; (f) 75.0 mL of 3.5×10−4 M HBr...
Sun Jan 24, 2021 9:22 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 6A.23 Textbook Question
Replies: 4
Views: 29

### 6A.23 Textbook Question

Calculate the molar concentration of Ba(OH)2(aq) and the molar concentrations of Ba2+, OH−, and H3O+ in an aqueous solution that contains 0.43 g of Ba(OH)2 in 0.100 L of solution. Hey guys! I was wondering if anyone could explain how we would begin to set up this problem? Would the amount of Ba(OH)2...
Sun Jan 24, 2021 9:12 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Determining Acid Dissociation
Replies: 2
Views: 16

### Determining Acid Dissociation

Hey guys! A couple of the questions for sapling #2 asked us to write equilibrium equations given certain strong/weak acids or bases. I was having a bit of difficulty understanding how an acid/base dissociates, and how to determine its conjugates. If anyone can explain some general guidelines or rule...
Sun Jan 24, 2021 8:56 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Spectator Ions
Replies: 6
Views: 55

### Spectator Ions

Hey guys!
On question six of the sapling homework #2, it used the term spectator ion in the explanation of the answer, and I was wondering if anyone could explain what that term means?
Thank you!
Sun Jan 24, 2021 8:50 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 5.35 Textbook Question
Replies: 1
Views: 23

### 5.35 Textbook Question

The following plot shows how the partial pressures of reactant and products vary with time for the decomposition of compound A into compounds B and C. All three compounds are gases. Use this plot to do the following: (a) Write a balanced chemical equation for the reaction. (b) Calculate the equilibr...
Sun Jan 17, 2021 6:10 pm
Forum: Phase Changes & Related Calculations
Topic: Determining Stronger Acids
Replies: 18
Views: 76

### Determining Stronger Acids

Hey guys! I had a question regarding how to determine which acids are stronger or weaker based off of pKa? Does the smaller pKa make the acid stronger or weaker?
Thank you!
Sun Jan 17, 2021 6:05 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Post Assessment Question 17 Part 4
Replies: 4
Views: 26

### Post Assessment Question 17 Part 4

17. Determine the shift in equilibrium, if any, which will occur for the following reactions when the temperature is increased a) Photosynthesis: 6 CO2 (g) + 6 H2O (l) ⇌ C6H12O6(s) + 6 O2 (g) delta H° = +2802 kJ.mol-1 b) The hydrolysis of ATP: ATP (aq) + H2O (l) ⇌ ADP + PO42-(aq) delta H° = -30 kJ.m...
Sun Jan 17, 2021 5:42 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Post Assessment Question 15 Part 4
Replies: 3
Views: 15

### Post Assessment Question 15 Part 4

15. The photosynthesis reaction, 6 CO2(g) + 6 H2O(l) ⇌ C6H12O6(aq) + 6 O2(g), is endothermic. What effect will the following changes have on the equilibrium composition. a) The partial pressure of CO2 is increased. b) The partial pressure of CO2 is decreased. Hey guys! I was wondering if anyone coul...
Sun Jan 17, 2021 5:38 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Post Assessment Part 4 Question 13
Replies: 1
Views: 7

### Post Assessment Part 4 Question 13

State whether the equilibrium shifts towards products, reactants, or neither when the given change occurs. 2 HI(g) + Cl2(g) ⇌ 2 HCl(g) + I2(s) delta H° = -238.0 kJ.mol-1. i. The volume of the system is compressed. ii. The temperature of the system is decreased. Hey guys! I was wondering if anyone co...
Sun Jan 17, 2021 5:33 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Textbook Problem 5I23
Replies: 3
Views: 33

### Textbook Problem 5I23

A reaction mixture consisting of 2.00 mol CO and 3.00 mol H2 is placed in a reaction vessel of volume 10.0 L and heated to 1200. K. At equilibrium, 0.478 mol CH4 was present in the system. Determine the value of Kc for the reaction CO(g) + 3H2(g)⇌CH4(g)+H2O(g) at 1200. K. Hey guys! For this problem,...
Sun Jan 10, 2021 10:24 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Chemical Equilibrium Part 2 Question 29
Replies: 2
Views: 14

### Chemical Equilibrium Part 2 Question 29

29) A researcher fills a 1.00 L reaction vessel with 1.84 x 10-4 mol of BrCl gas and heats it to 500 K. At equilibrium, only 18.3 % of the BrCl gas remains. Calculate the equilibrium constant, assuming the following reaction is taking place. 2BrCl(g) ⇌ Br2 (g) + Cl2(g) Hey guys! I was having difficu...
Sun Jan 10, 2021 10:19 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Chemical Equilibrium Part 2 Question 27
Replies: 3
Views: 27

### Chemical Equilibrium Part 2 Question 27

27) A mixture of 2.5 moles H2O and 100 g of C are placed in a 50 L container and allowed to come to equilibrium subject to the following reaction: C(s) + H2O (g) ⇌ CO (g) + H2 (g) The equilibrium concentration of hydrogen is found to be [H2] = 0.040 M. What is the equilibrium concentration of water,...
Sun Jan 10, 2021 10:15 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Chemical Equilibrium Part 2 Question 26
Replies: 1
Views: 9

### Chemical Equilibrium Part 2 Question 26

26) A mixture initially consisting of 0.250 N2 (g) and 0.500 M H2 (g) reacts to form NH3 (g) which is 0.15 M NH3 (g) at equilibrium. Calculate the concentration of N2 (g) at equilibrium for the reaction N2(g) + 3H2(g) ⇌ 2NH3(g). Hey guys! I was wondering if anyone could explain how I would specifica...
Sun Jan 10, 2021 10:09 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Post Assessment Chemical Equilibrium Part 2 Question 30
Replies: 2
Views: 11

### Post Assessment Chemical Equilibrium Part 2 Question 30

A mixture of 2.5 moles H2O and 100 g of C are placed in a 50 L container and allowed to come to equilibrium subject to the following reaction: C(s) + H2O (g) ⇌ CO (g) + H2 (g). The equilibrium concentration of hydrogen is found to be [H2] = 0.040 M. Calculate the equilibrium constant Kc of this reac...
Sun Jan 10, 2021 10:03 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Post Assessment Chemical Equilibrium Part 2 Question 12
Replies: 1
Views: 12

### Post Assessment Chemical Equilibrium Part 2 Question 12

12) Consider the following reaction at 1200 K, for which you know Kc = 1.7 x 10-3. Br2 (g) ⇌ 2 Br (g) Your experimental setup is able to measure the equilibrium concentration of Br2 based on its color, but you are unable to measure the concentration of Br directly. If you measure at equilibrium [Br2...
Wed Dec 16, 2020 3:26 am
Forum: Naming
Topic: Determining charge when naming formulas
Replies: 3
Views: 43

### Determining charge when naming formulas

Hey guys!
When we are naming compounds, sometimes there are elements in the compound that have a charge like +2 or -1, and I was wondering what we would do in those situations? How would I incorporate the charge into my final answer when writing the name of the compound? Thanks in advance!
Wed Dec 16, 2020 3:21 am
Forum: Amphoteric Compounds
Topic: Amphoteric Compounds trend
Replies: 2
Views: 41

### Amphoteric Compounds trend

Hey guys!
I was wondering if there was a simple way to identify amphoteric compounds from trends on the periodic table? I believe I read somewhere that amphoteric compounds tend to either be transition metals or metalloids, and I was wondering if anyone could clarify that? Thanks in advance!
Wed Dec 16, 2020 3:12 am
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Difference between pH and pOH
Replies: 12
Views: 120

### Difference between pH and pOH

Hey guys!
I was wondering if anyone could explain the conceptual difference between pH, pOH, Kb, and pKb? Thanks in advance!
Wed Dec 16, 2020 3:07 am
Forum: Conjugate Acids & Bases
Topic: Bronsted Conjugates vs Lewis Conjugates
Replies: 1
Views: 35

### Bronsted Conjugates vs Lewis Conjugates

Hey guys!
When conjugating bases and acids, do the structures you draw vary on whether you are doing a Bronsted or a Lewis acid/base? Thanks in advance!
Wed Dec 16, 2020 3:00 am
Forum: Lewis Structures
Topic: Transition Metals Lewis Structures
Replies: 3
Views: 45

### Transition Metals Lewis Structures

Hey guys!
For a couple of problems in the textbook, I noticed that there were some questions where the transition metal was the central atom in a Lewis structure, and I was wondering if anyone knew how to determine the number of valence electrons that a transition metal has? Thanks in advance!
Sun Dec 06, 2020 9:37 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Finding differences in pH
Replies: 1
Views: 23

### Finding differences in pH

Hey guys! I was having difficulty with textbook problem 6B1 in the textbook which states: The molar concentration of HCl in hydrochloric acid is reduced to 12% of its initial value by dilution. What is the difference in the pH values of the two solutions? I was wondering what the best way to approac...
Sun Dec 06, 2020 9:31 pm
Forum: Conjugate Acids & Bases
Topic: Textbook Problem 6A3
Replies: 1
Views: 19

### Textbook Problem 6A3

Hey guys! I was having a bit of difficulty completing the following problem in the textbook: Write the chemical equations for the proton transfer equilibria of the following acids in aqueous solution and identify the conjugate acid–base pairs in each case: (a) H2SO4 I was wondering if anyone could e...
Sun Dec 06, 2020 9:22 pm
Forum: Lewis Acids & Bases
Topic: Fundamentals J Problem 7
Replies: 1
Views: 18

### Fundamentals J Problem 7

Hey guys! I was having difficulty solving one of the problems in the fundamentals J section that is about acids and bases. The problem is: Select an acid and a base for a neutralization reaction that results in the formation of (a) potassium bromide; (b) zinc nitrite; (c) calcium cyanide, Ca(CN)2 (d...
Sun Dec 06, 2020 8:51 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Textbook Problem 9C7
Replies: 1
Views: 17

### Textbook Problem 9C7

Hey guys! I was wondering if anyone could explain how we can determine which structures can form chelating complexes? I have come across this term a couple of times in different problems regarding ligands, however, I am confused as to what this term means, or how I can apply it in problems. Thanks i...
Sun Dec 06, 2020 8:42 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Textbook Problem 9C5
Replies: 1
Views: 35

### Textbook Problem 9C5

Hey guys! I was having a bit of trouble figuring part B of question 9C5 in the textbook. The problem is: Which of the following ligands can be polydentate? If the ligand can be polydentate, give the maximum number of places on the ligand that can bind simultaneously to a single metal center? b) CO3^...
Sun Nov 29, 2020 5:24 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Textbook Problem 2F3
Replies: 4
Views: 47

### Textbook Problem 2F3

Hey guys! Question 3 in section 2F of the textbook asks: How many σ-bonds and how many π-bonds are there in (a) H2S and (b) SO2? I know that the first step I should take in this problem is to draw the Lewis structure of both molecules, but I was wondering how to approach this problem after completin...
Sun Nov 29, 2020 5:19 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Textbook Problem 2E27
Replies: 4
Views: 12

### Textbook Problem 2E27

Hey guys! Question 27 of section 2E in the textbook asks: Predict whether each of the following molecules is likely to be polar or nonpolar: (a) (pyridine, a molecule like benzene except that one group is replaced by a nitrogen atom); (b) (ethane); (c) (trichloromethane, also known as chloroform, a ...
Sun Nov 29, 2020 5:09 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Textbook Problem 2E11
Replies: 3
Views: 34

### Textbook Problem 2E11

Hey guys! Question 11 of section 2E in the book asks: Use Lewis structures and the VSEPR model to give the VSEPR formula for each of the following species and predict its shape: (a) sulfur tetrachloride; (b) iodine trichloride; (c) (d) xenon trioxide. I was wondering if anyone could explain what exa...
Sun Nov 29, 2020 5:03 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Textbook Problem 2E5
Replies: 3
Views: 31

### Textbook Problem 2E5

Hey guys! I was wondering if anyone could explain textbook question 2E5. It states: (a) What is the shape of a ion? (b) What is the expected OClO bond angle? For part A I was wondering if the shapes of all ions are the same no matter what? And for part B, does the bond angle depend on the unpaired e...
Sun Nov 29, 2020 4:55 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Textbook Problem 2E1
Replies: 1
Views: 19

### Textbook Problem 2E1

Hey guys! The first question in section 2E of the textbook states: Below are ball-and-stick models of two molecules. In each case, indicate whether there must be, may be, or cannot be one or more lone pairs of electrons on the central atom. One molecule has a 120 degree angle, and the other has a 18...
Sun Nov 22, 2020 11:21 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Axial vs Equatorial atoms
Replies: 8
Views: 106

### Axial vs Equatorial atoms

Hey guys!
I was wondering if anyone could explain the difference between axial and equatorial atoms? Also, will we always be given a model of the molecule that we can rotate around to be able to specify which atoms are which more easily? Thanks in advance!
Sun Nov 22, 2020 10:48 pm
Forum: Hybridization
Topic: Determining Hybridization
Replies: 1
Views: 20

### Determining Hybridization

Hey guys! I was working on the homework from this week, and I was getting pretty confused on how to solve hybridization problems. If anyone could give me some general concepts/steps to keep in mind when solving problems (especially when it comes to steric number), it would really help a lot. Thanks ...
Sun Nov 22, 2020 10:44 pm
Forum: Dipole Moments
Topic: Determining higher dipole moments
Replies: 5
Views: 67

### Determining higher dipole moments

Hey guys!
I was wondering if anyone could explain how you can tell which molecule has a higher dipole moment from just a lewis structure? Thanks in advance!
Sun Nov 22, 2020 10:21 pm
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: Determining Non-Polarity
Replies: 5
Views: 62

### Determining Non-Polarity

Hi guys! I was practicing some questions on the sapling homework, and I was wondering how to determine polarity based off of Lewis structures only. Do all the valence electrons of a central atom have to be paired to be considered a nonpolar molecule? Or do the valence electrons just have to be share...
Sun Nov 22, 2020 10:06 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Defining VSEPR Theory
Replies: 4
Views: 22

### Defining VSEPR Theory

Hey guys!
I was doing the sapling homework and I was struggling a bit with the situations revolving VSEPR theory. I was wondering if anyone could clarify the VSEPR theory and explain how I can apply it to find the smallest bond angle in a molecule. Thanks in advance!
Sun Nov 15, 2020 11:23 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Steps to writing ground state electron configuration
Replies: 2
Views: 28

### Steps to writing ground state electron configuration

Hey guys!
I was working on some textbook problems when I came across a couple that asked me to write the ground state configuration for atoms. I was wondering if anyone had a couple of simple steps that we are supposed to use when solving these kinds of problems? Thanks in advance!
Sun Nov 15, 2020 11:16 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Electron Shielding
Replies: 1
Views: 8

### Electron Shielding

Hey guys! I was wondering if anyone could clarify the topic of electron shielding? I was having difficulty with some of the problems in the 1E section of the textbook that revolved around that concept, and I mainly struggle with which orbital (s,p,d, or f) has the best shielding mechanisms. Thanks i...
Sun Nov 15, 2020 11:13 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Effective Nuclear Charge
Replies: 6
Views: 70

### Effective Nuclear Charge

Hey guys!
I was doing some textbook problem practice, and I came across a couple of questions that asked about effective nuclear charge. I was wondering if anyone could clarify this topic for me, and how effective nuclear charge relates to the number of electrons in an atom? Thanks in advance!
Sun Nov 15, 2020 9:41 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Section 1D #25
Replies: 2
Views: 63

### Section 1D #25

Hey guys!
I came across this problem in section 1D:
Which of the following subshells cannot exist in an atom: (a) 2d; (b) 4d; (c) 4g; (d) 6f?
I was wondering if anyone could explain the conditions needed for a subshell to exist/not exist? Thanks in advance!
Sun Nov 15, 2020 9:36 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Determining Number of Orbitals
Replies: 3
Views: 45

### Determining Number of Orbitals

Hey guys! I was doing the textbook problems and I came across this problem in section 1D practices: How many orbitals can have the following quantum numbers in an atom: b)n=4, l=2,m=-2 c)n=2 I understand part A and D for this question, but I was wondering if someone could clarify how to get the answ...
Sun Nov 08, 2020 6:49 pm
Forum: Ionic & Covalent Bonds
Topic: Identifying Ionic and Covalent Bonds
Replies: 10
Views: 44

### Identifying Ionic and Covalent Bonds

When doing the sapling homework I came across a problem that asked me to identify certain bonds as either ionic or covalent. For ionic bonds, I know that these are formed when oppositely charged ions share electrons, and the more electronegative ion hogs the electrons, but I am a bit confused on how...
Sun Nov 08, 2020 6:34 pm
Forum: Lewis Structures
Topic: Lewis Acid vs. Lewis Base
Replies: 5
Views: 58

### Lewis Acid vs. Lewis Base

On Sapling there was a question that asked us to classify elements or molecules into the category of a Lewis base or Lewis acid. I noticed that Carbon Dioxide was labeled as a Lewis acid, and I was wondering if anyone could explain why. Thanks in advance!
Sun Nov 08, 2020 6:23 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Energy Levels in electron configurations
Replies: 5
Views: 33

### Energy Levels in electron configurations

When rewatching the lecture on how to write electron configurations, I noticed that professor explained that we write 3d before 4s in electron configurations because 3d has a lower energy level, and electron configurations go from lowest to highest energy levels. I was wondering if anyone could re-e...
Sun Nov 08, 2020 6:18 pm
Forum: Trends in The Periodic Table
Topic: Elements that form Cations
Replies: 6
Views: 27

### Elements that form Cations

I was wondering if anyone could explain why the elements on the left side of the periodic table are more likely to form cations? Does it have to do with the amount of valence electrons that an element has? Thanks in advance!
Sun Nov 08, 2020 6:15 pm
Forum: Trends in The Periodic Table
Topic: Octet Rule
Replies: 6
Views: 50

### Octet Rule

When listening to the lecture, professor mentioned that the exceptions to the octet rule include H, He, Be, and Li. I was wondering if anyone could explain why these are exceptions to the octet rule. Is it because of the low number of valence electrons? Thanks in advance!
Sun Nov 01, 2020 7:52 pm
Forum: Trends in The Periodic Table
Replies: 3
Views: 29

Throughout the Sapling homework this week, I noticed that several questions asked me to rearrange different elements off of their atomic or ionic radius. I was wondering what is the difference between both the ionic and atomic radius, and how I could identify each? Thanks in advance!
Sun Nov 01, 2020 7:50 pm
Forum: Trends in The Periodic Table
Topic: Determining size of Atomic Radius
Replies: 2
Views: 20

### Determining size of Atomic Radius

On the Sapling homework for this week, I came across a couple of questions that asked me to rearrange elements in order of increasing size of atomic radius. I was wondering if anyone knew a conceptual approach for this problem? For example, are there trends in the periodic table that tell me which e...
Sun Nov 01, 2020 7:47 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: How to Calculate Ground State
Replies: 3
Views: 24

### How to Calculate Ground State

I was doing the Sapling homework and I came across a problem where it asked us to write the ground state from the excited state. I was wondering how I would go about solving this problem? Also, what is the difference between the ground state and excited state? Thanks in advance!
Sun Nov 01, 2020 7:44 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Writing Electronic Configurations
Replies: 8
Views: 50

### Writing Electronic Configurations

When I was completing the Sapling homework for this week, I noticed that one question asked us to write the electronic configuration for F, and it had He written at the beginning of the configuration (because it holds a max of two electrons for that first shell?) and I was wondering if we have to wr...
Sun Nov 01, 2020 7:41 pm
Forum: Quantum Numbers and The H-Atom
Topic: Determining Quantum Numbers
Replies: 5
Views: 50

### Determining Quantum Numbers

On Sapling, there are a couple questions regarding determining the number of electrons an atom could hold. For example, one question gives us the conditions of when n=7, l=1, and m=-1. I was wondering how I would go figuring out this problem? Thanks in advance!
Sun Oct 25, 2020 6:27 pm
Forum: DeBroglie Equation
Topic: Determining KE from the De Broglie Equation
Replies: 2
Views: 27

### Determining KE from the De Broglie Equation

On Sapling there is a question that reads: You use an electron microscope in which the matter wave associated with the electron beam has a wavelength of 0.0191 nm. What is the kinetic energy of an electron in the beam, expressed in eV? We are given mass and wavelength, meaning we can use the De Brog...
Sun Oct 25, 2020 6:21 pm
Forum: DeBroglie Equation
Topic: Determining Energy of a Photon
Replies: 5
Views: 49

### Determining Energy of a Photon

On sapling there is a question that reads: The E. Coli bacterium is about 2.5 micrometers long. Suppose you want to study it using photons of that wavelength or electrons having that de Broglie wavelength. What is the energy of the photon? Since they mention using the De Broglie equation to solve th...
Sun Oct 25, 2020 6:17 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Minimum uncertainty problems
Replies: 3
Views: 31

### Minimum uncertainty problems

On Sapling, there is a question that reads: What is the minimum uncertainty in an electron's velocity if the position is known within 13 angstroms? I was wondering if there is a difference between minimum uncertainty in terms of using a particular formula, or are we just supposed to use the regular ...
Sun Oct 25, 2020 6:05 pm
Forum: Photoelectric Effect
Topic: Textbook Problem 1B7
Replies: 4
Views: 73

### Textbook Problem 1B7

Sodium vapor lamps, used for public lighting, emit yellow light of wavelength 589 nm. How much energy is emitted by (a) an excited sodium atom when it generates a photon; (b) 5.00 mg of sodium atoms emitting light at this wavelength; (c) 1.00 mol of sodium atoms emitting light at this wavelength? I ...
Sun Oct 25, 2020 5:56 pm
Forum: Photoelectric Effect
Topic: Textbook Problem 1B3
Replies: 1
Views: 31

### Textbook Problem 1B3

From the following list of observations, select the one that best supports the idea that electromagnetic radiation has the properties of particles. Explain your reasoning. (a) Black-body radiation. (b) Electron diffraction. (c) Atomic spectra. (d) The photoelectric effect. So for this question, I th...
Sat Oct 17, 2020 6:09 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Heisenberg Post Assessment Q#23
Replies: 1
Views: 20

### Heisenberg Post Assessment Q#23

You are caught in a radar trap and hope to show that the speed measured by the radar gun is in error due to the Heisenberg uncertainty principle. If you assume that the uncertainty in your position was +/- 5 m when your speed was measured, and that the car has a mass of 2150 kg, what is your calcula...
Sat Oct 17, 2020 5:43 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Heisenberg Uncertainty Principle Post Assessment Q#18
Replies: 2
Views: 54

### Heisenberg Uncertainty Principle Post Assessment Q#18

The hydrogen atom has a radius of approximately 0.05 nm. Assume that we know the position of an electron to an accuracy of 1 % of the hydrogen radius, calculate the uncertainty in the speed of the electron using the Heisenberg uncertainty principle. Does anyone know the steps I have to take to solve...
Sat Oct 17, 2020 5:27 pm
Forum: Photoelectric Effect
Topic: Textbook Problem 1A9
Replies: 4
Views: 37

### Textbook Problem 1A9

A college student recently had a busy day. Each of the student’s activities on that day (reading, getting a dental x-ray, making popcorn in a microwave oven, and acquiring a suntan) involved radiation from a different part of the electromagnetic spectrum. Complete the following table and match each ...
Sat Oct 17, 2020 5:10 pm
Forum: Properties of Light
Topic: Textbook Problem 1B15
Replies: 2
Views: 42

### Textbook Problem 1B15

The velocity of an electron that is emitted from a metallic surface by a photon is 3.6 x 10^3 km/s. What is the wavelength of the ejected electron? So I have tried a couple different formulas for this problem, but I seem to always be missing a variable and cannot calculate this equation fully, does ...
Sat Oct 17, 2020 5:04 pm
Forum: Properties of Light
Topic: Textbook Problems (Topic 1B)
Replies: 1
Views: 38

### Textbook Problems (Topic 1B)

Hey guys! I was practicing the textbook problems and I am having difficulty with problem 1B5 which states: The γ-ray photons emitted by the nuclear decay of a technetium-99 atom used in radiopharmaceuticals have an energy of 140.511 keV. Calculate the wavelength of these γ-rays. So far I know that I...
Sun Oct 11, 2020 1:59 am
Forum: Properties of Electrons
Topic: Calculating Kinetic Energy
Replies: 1
Views: 77

### Calculating Kinetic Energy

Hey guys! I was struggling a bit with one of the problems on the audio visual modules. That problem states: If molybdenum is irradiated with 194 nm light, what is the maximum possible kinetic energy of the emitted electrons? I honestly don't know how exactly to approach this problem, and I am mostly...
Sun Oct 11, 2020 1:36 am
Forum: Properties of Light
Topic: Calculating Properties of Incident Light Problems
Replies: 1
Views: 27

### Calculating Properties of Incident Light Problems

Hey guys! I had some difficulties with a problem from one of the audio visual topics. The problem is: A) If 3.607 x 10^19 J is required to remove an electron with zero kinetic energy from a metal surface, what would be the longest wavelength light that could do this? B) In a second experiment a shor...
Sun Oct 11, 2020 1:19 am
Forum: Properties of Light
Topic: Photoelectric effect Problem Audio Visual Topics Q28
Replies: 4
Views: 32

### Photoelectric effect Problem Audio Visual Topics Q28

Hey guys! I was doing some problems for the photoelectric effect audio visual modules and I was having difficulty with problem 28 which states: Light hits a sodium metal surface and the velocity of the ejected electron is 6.61 x 10^5 m.s^-1. The work function for sodium is 150.6 kJ.mol-1. Answer the...
Wed Oct 07, 2020 12:25 pm
Forum: Empirical & Molecular Formulas
Topic: Fundamentals F Problem 27
Replies: 1
Views: 72

### Fundamentals F Problem 27

Hey guys! Problem F.27 came up during my chemistry discussion today and the problem states: A mixture of NaNO3 and Na2SO4 of mass 5.37 g contains 1.61 g of sodium. What is the percentage by mass of NaNO3 in the mixture? I'm having difficulties starting the problem because I am unsure of which mass g...
Wed Oct 07, 2020 11:47 am
Forum: SI Units, Unit Conversions
Topic: Sapling Assignment 1 Question 6
Replies: 16
Views: 133

### Sapling Assignment 1 Question 6

Hey guys! I was wondering if anyone could explain how to properly convert the units on problem number 6 of the sapling homework. The problem is: If 2.92 g of CuNO3 is dissolved in water to make a 0.260 M solution, what is the volume of the solution in milliliters? So far I know that I have to use th...