Search found 63 matches
- Sat Mar 16, 2019 7:05 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Assuming ideal gas
- Replies: 3
- Views: 611
Re: Assuming ideal gas
should usually assume, sometimes question also mentions it explicitly
- Sat Mar 16, 2019 6:59 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Equilibrium constant
- Replies: 5
- Views: 452
Re: Equilibrium constant
Catalyst has no effect on the equilibrium
- Sat Mar 16, 2019 6:58 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Shifting K with changes in volume
- Replies: 4
- Views: 637
Re: Shifting K with changes in volume
Yes, less pressure (greater volume) will cause shift to side with more gas moles
- Sat Mar 16, 2019 6:57 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Midterm, Question 2.B
- Replies: 3
- Views: 442
Re: Midterm, Question 2.B
1/K , which is the inverse I believe
- Sat Mar 16, 2019 6:56 pm
- Forum: Ideal Gases
- Topic: Ideal gas constant R
- Replies: 10
- Views: 1565
Re: Ideal gas constant R
depends on the units in the question
- Tue Mar 12, 2019 12:17 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: stability of reactants and products
- Replies: 3
- Views: 478
Re: stability of reactants and products
Spontaneous reaction means products are more stable whilst spontaneous means the reactants will be more stable
- Mon Mar 11, 2019 8:09 pm
- Forum: Calculating Work of Expansion
- Topic: Work
- Replies: 8
- Views: 908
Re: Work
whichever best suits and demands and variables of the question
- Mon Mar 11, 2019 8:07 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: Work done vs work on system
- Replies: 18
- Views: 3800
Re: Work done vs work on system
work done by the system is negative, work done on the system is positive
- Mon Mar 11, 2019 8:04 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Entropy based on shape of molecule
- Replies: 3
- Views: 418
Re: Entropy based on shape of molecule
entropy is greater for more complex molecules, so trans would be greater entrophy
- Mon Mar 11, 2019 8:03 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Equilibrium Constant and Temperature
- Replies: 2
- Views: 351
Re: Equilibrium Constant and Temperature
i believe standard temperature is 25 C. /298 K, and the question may also state it
- Mon Mar 11, 2019 8:02 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Formulas
- Replies: 6
- Views: 607
Re: Formulas
whichever is best suited to the needs and variables of the question
- Mon Mar 11, 2019 8:01 pm
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: Calculating entropy
- Replies: 5
- Views: 431
Re: Calculating entropy
we isolate the two changes in entrophy and then add together
- Mon Mar 11, 2019 7:59 pm
- Forum: Phase Changes & Related Calculations
- Topic: Steam vs Boiling Water
- Replies: 8
- Views: 1167
Re: Steam vs Boiling Water
greater enthalpy and therefore more heat in steam
- Mon Mar 11, 2019 7:57 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Finding heat(q)
- Replies: 3
- Views: 361
Re: Finding heat(q)
yes, depends on which is best suited to the question
- Mon Mar 11, 2019 7:56 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Delta U
- Replies: 5
- Views: 785
Re: Delta U
Yes because if temperature is constant/not changing then the internal energy is therefore 0
- Mon Mar 11, 2019 7:54 pm
- Forum: Ideal Gases
- Topic: ICE
- Replies: 8
- Views: 641
Re: ICE
x can be ignored, making x equal to 0
- Mon Mar 11, 2019 7:53 pm
- Forum: Ideal Gases
- Topic: Cell Diagram/Ecell
- Replies: 8
- Views: 917
Re: Cell Diagram/Ecell
cathode gains electrons(reduction) whilst the anode loses electrons (oxidation)
- Mon Mar 11, 2019 7:52 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Le Chatelier's Principle
- Replies: 3
- Views: 358
Re: Le Chatelier's Principle
the effects of temperature, pressure, adding or removal of reactants or products, or adding of inert gases on the equilibrium and if there will be shifts to left or right or no shift at all
- Sun Mar 10, 2019 7:52 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Constant Vol.
- Replies: 8
- Views: 1042
Re: Constant Vol.
Work is zero if no change in volume as there is no expansion or compression
- Sun Mar 10, 2019 7:49 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Injecting noble gasses
- Replies: 7
- Views: 761
Re: Injecting noble gasses
Noble and inert gasses will cause no shift and no change in equilibrium constant
- Sun Mar 10, 2019 7:48 pm
- Forum: Ideal Gases
- Topic: How do I know what is an Ideal Gas
- Replies: 11
- Views: 912
Re: How do I know what is an Ideal Gas
I think we are supposed to assume the gases in the questions are ideal gases. Sometimes the question will state it as well.
- Sun Mar 10, 2019 7:46 pm
- Forum: Ideal Gases
- Topic: sre
- Replies: 5
- Views: 573
Re: sre
enthalpy of standard state for reactants and products (which are in their standard states)
- Sun Mar 10, 2019 7:41 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: ignoring x
- Replies: 16
- Views: 3231
Re: ignoring x
X is zero if follows 5% rule or if K is less than 10^-3. Therefore no need to use quadratic equation
- Sun Mar 10, 2019 7:39 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Stability of reactants and products Midterm question
- Replies: 3
- Views: 654
Re: Stability of reactants and products Midterm question
The products will be more stable than the reactants when the equilibrium constant K is large
- Sun Mar 10, 2019 7:38 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Units of Kp
- Replies: 9
- Views: 3609
Re: Units of Kp
Bars or atms I believe
- Sun Mar 10, 2019 7:37 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Approximation
- Replies: 7
- Views: 1243
Re: Approximation
Approximate if it follows 5% rule or equilibrium constant is below x10^-3. But I sometimes use quadratic anyway to double check. :)
- Sun Mar 10, 2019 7:35 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Midterm Ice Table
- Replies: 6
- Views: 657
Re: Midterm Ice Table
I believe we were not supposed to approximate and instead use the quadratic formula
- Sun Mar 10, 2019 7:33 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Reverse Reaction
- Replies: 8
- Views: 763
Re: Reverse Reaction
Reverse reaction is 1/K, inverse relationship
- Sun Mar 10, 2019 7:33 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Midterm
- Replies: 5
- Views: 529
Re: Midterm
The bigger the equilibrium constant, the more stable the products are
- Sun Mar 10, 2019 7:32 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Negligible X
- Replies: 3
- Views: 380
Re: Negligible X
X is zero if 5% of initial concentration or if K less than 10^-3
- Sun Mar 10, 2019 7:30 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Equilibrium constant
- Replies: 3
- Views: 286
Re: Equilibrium constant
No units for K
- Sun Mar 10, 2019 7:30 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Equation I've never seen before?
- Replies: 3
- Views: 400
Re: Equation I've never seen before?
appears to be a form of PV=nrt
- Sun Mar 10, 2019 7:29 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Final Exam
- Replies: 23
- Views: 1733
Re: Final Exam
for sure will be on the final
- Sat Dec 08, 2018 7:16 pm
- Forum: Accuracy, Precision, Mole, Other Definitions
- Topic: ions
- Replies: 4
- Views: 713
Re: ions
Cations lose electrons, giving a positive charge
- Sat Dec 08, 2018 7:11 pm
- Forum: Lewis Acids & Bases
- Topic: H-
- Replies: 3
- Views: 303
Re: H-
Bronsted base because H- is a proton acceptor
- Sat Dec 08, 2018 7:07 pm
- Forum: Lewis Structures
- Topic: Lewis Acids & Bases
- Replies: 3
- Views: 600
Re: Lewis Acids & Bases
Lewis acids are defined as accepting a pair of electrons whilst the Lewis bases are donors of electrons. So it would be based on whether the molecule accepts or gives electron pairs
- Sat Dec 08, 2018 7:03 pm
- Forum: Electronegativity
- Topic: Exceptions
- Replies: 3
- Views: 696
Re: Exceptions
I do not think there are exceptions to the electronegativity trend which goes up and to the right on the periodic table
- Sat Dec 08, 2018 7:02 pm
- Forum: Hybridization
- Topic: Expanded Octet Hybridizations
- Replies: 2
- Views: 453
Re: Expanded Octet Hybridizations
because d orbitals allow those elements to have expanded octets so hybridization can show the d along with the s and p orbitals due to the large amount of valence electrons
- Fri Dec 07, 2018 8:33 pm
- Forum: Lewis Acids & Bases
- Topic: Lewis v Bronsted
- Replies: 2
- Views: 157
Re: Lewis v Bronsted
Lewis describes lewis acid as an acceptor of a lone pair of electrons whilst Bronstead describes an acid as a donor of a proton
- Fri Dec 07, 2018 8:31 pm
- Forum: Lewis Structures
- Topic: Elements that break the octet rule
- Replies: 6
- Views: 831
Re: Elements that break the octet rule
The elements in the d block can violate the octet rule because of the presence of the d orbital into which more electrons can reside
- Fri Dec 07, 2018 8:30 pm
- Forum: Hybridization
- Topic: pi vs sigma
- Replies: 12
- Views: 1188
Re: pi vs sigma
Sigma bonds overlap more than pi bonds, allowing for more strength whilst also allowing for rotation
- Fri Dec 07, 2018 8:27 pm
- Forum: Polarisability of Anions, The Polarizing Power of Cations
- Topic: Polarizing Power: Size vs. Charge
- Replies: 4
- Views: 693
Re: Polarizing Power: Size vs. Charge
Smaller atomic radius cations have more polarizing power. A higher charge also gives more polarizing power
- Fri Dec 07, 2018 8:25 pm
- Forum: Octet Exceptions
- Topic: Exceptions
- Replies: 10
- Views: 1331
Re: Exceptions
elements in the d block are exceptions as they are able to fill their d orbital with more electrons, allowing for an expanded octet
- Fri Dec 07, 2018 8:23 pm
- Forum: Electronegativity
- Topic: Ionic Character
- Replies: 7
- Views: 1516
Re: Ionic Character
I believe oxygen is more electronegative as it is higher than chlorine on the periodic table
- Fri Dec 07, 2018 8:21 pm
- Forum: Sigma & Pi Bonds
- Topic: Number of sigma and pi bonds
- Replies: 5
- Views: 1025
Re: Number of sigma and pi bonds
a single bond corresponds to a sigma bond, whilst a double bond is 1 sigma and 1 pi and a triple bond is 1 sigma and 2 pis
- Fri Dec 07, 2018 8:18 pm
- Forum: Properties of Electrons
- Topic: Orbitals
- Replies: 5
- Views: 780
Re: Orbitals
p shell has 3 orbitals I believe
- Fri Dec 07, 2018 8:15 pm
- Forum: Properties of Light
- Topic: Speed of light
- Replies: 13
- Views: 3846
Re: Speed of light
3X10^8 should be fine I think
- Sun Nov 25, 2018 8:13 pm
- Forum: Hybridization
- Topic: 2F.1 7th Edition
- Replies: 1
- Views: 100
2F.1 7th Edition
Can someone explain the solution for 2F.1 in the 7th Edition? "State the relative orientation of each of the following hybrid orbitals: (a)sp^3; (b) sp; (c)sp^3d^2; (d) sp^2.
- Sun Nov 25, 2018 8:06 pm
- Forum: Hybridization
- Topic: Octet Expansion
- Replies: 6
- Views: 489
Re: Octet Expansion
electrons fill up the s and p orbital. once those orbitals are filled, d orbital is needed for an atom to have more than 8 valence electrons
- Sun Nov 25, 2018 8:01 pm
- Forum: Bond Lengths & Energies
- Topic: Why Are Double Bonds Shorter
- Replies: 16
- Views: 6050
Why Are Double Bonds Shorter
Howdy partners. What is the reasoning for why double bonds are shorter (and therefore stronger) than single bonds? Thanks
- Sun Nov 25, 2018 7:53 pm
- Forum: Octet Exceptions
- Topic: Understanding Expanded Octets
- Replies: 1
- Views: 342
Understanding Expanded Octets
Howdy. Can one of ya'll explain how having a greater number of orbitals, such as a d orbital, allow an element to have an expanded octet? Thanks.
- Sun Oct 28, 2018 8:15 pm
- Forum: Ionic & Covalent Bonds
- Topic: 2A.21 7th Edition Question
- Replies: 2
- Views: 257
2A.21 7th Edition Question
Howdy ya'll. Can someone explain why the ground state electron configuration for Ag^+ is [Kr]4d^10 in question 2A.21? Thanks
- Sun Oct 28, 2018 8:06 pm
- Forum: Ionic & Covalent Bonds
- Topic: 2A.6 7th Edition
- Replies: 1
- Views: 85
2A.6 7th Edition
Howdy! 2A.6 asks for the ground-state electron configuration of the ion P^3-. Can someone explain how I would go about solving this?
- Sun Oct 28, 2018 8:00 pm
- Forum: Ionic & Covalent Bonds
- Topic: Question regarding ionic bonds
- Replies: 9
- Views: 607
Question regarding ionic bonds
Howdy partners. Are ionic bonds always between non-metals and metals?
- Sun Oct 21, 2018 8:02 pm
- Forum: Properties of Electrons
- Topic: Concept Behind Orbitals
- Replies: 6
- Views: 567
Concept Behind Orbitals
Howdy there. I was wondering about the conceptual explanation behind why higher orbitals have more energy. Is it because of distance from the positively charged nucleus?
- Sun Oct 21, 2018 8:00 pm
- Forum: Heisenberg Indeterminacy (Uncertainty) Equation
- Topic: HW Question Regarding 1B.27
- Replies: 6
- Views: 581
HW Question Regarding 1B.27
Howdy! 1B.27 says "A bowling ball of masss 8.00 kg is rolled down a bowling alley lane at 5.00 +/ 5.0 m/s. What is the minimum uncertainty in its position?" Can one of ya'll explain to me how I use the uncertainty equation to obtain the minimum uncertainty?
- Sun Oct 21, 2018 7:55 pm
- Forum: DeBroglie Equation
- Topic: 1B. 25 7th Edition
- Replies: 2
- Views: 227
1B. 25 7th Edition
Howdy ya'll. 1B.25 states "What is the minimum uncertainty in the speed of an electron confined within a lead atom of diameter 350 pm? Can somebody explain how to obtain the solution please. Thanks
- Sun Oct 14, 2018 8:25 pm
- Forum: Properties of Light
- Topic: Photons
- Replies: 4
- Views: 243
Re: Photons
A single photon requires the sufficient energy needed to remove a single electron. :)
- Sun Oct 14, 2018 8:23 pm
- Forum: Properties of Light
- Topic: Measurable Wavelengths
- Replies: 3
- Views: 184
Measurable Wavelengths
Does anybody know how long a wavelength must be to be "measurable"?
- Sun Oct 14, 2018 8:19 pm
- Forum: Properties of Light
- Topic: 1A.3 7th Edition Question
- Replies: 4
- Views: 439
1A.3 7th Edition Question
1A.3 Which of the following happens when the frequency of electromagnetic radiation decreases? Explain your reasoning. (c) The extent of the change in the electrical field at a given point decreases. Can someone explain what happens to the "extent of the change in the electrical field at a give...
- Sun Oct 07, 2018 6:09 pm
- Forum: Accuracy, Precision, Mole, Other Definitions
- Topic: E15 7th Edition
- Replies: 1
- Views: 211
E15 7th Edition
The molar mass of the metal hydroxide M(OH)2 is 74.10 gmol. What is the molar mass of the sulfide of this metal? I understand how to obtain molar mass but how do I identify the sulfide of M(OH)2? Thanks
- Sun Oct 07, 2018 6:06 pm
- Forum: SI Units, Unit Conversions
- Topic: Question regarding showing units within work
- Replies: 2
- Views: 255
Question regarding showing units within work
When working on the answer to a question, does anybody know if we have to show units in our work? I understand our final answer must have units.
- Sun Oct 07, 2018 6:03 pm
- Forum: Accuracy, Precision, Mole, Other Definitions
- Topic: Atomic Weight vs Molecular Weight
- Replies: 2
- Views: 276
Re: Atomic Weight vs Molecular Weight
I believe atomic weight is the measured weight of the atom whilst the molecular weight is the measured weight of the molecule (so add weights of the atoms within the molecule). ;)