Search found 56 matches
- Sun Mar 01, 2020 8:57 pm
- Forum: General Science Questions
- Topic: Studying
- Replies: 67
- Views: 3510
Re: Studying
practice problems
- Sun Mar 01, 2020 8:56 pm
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: electrolysis
- Replies: 6
- Views: 447
Re: electrolysis
yes
- Sun Mar 01, 2020 8:55 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: cell potential
- Replies: 15
- Views: 770
Re: cell potential
if Ecell is positive, delta G will be negative meaning the reaction is spontaneous
- Sun Mar 01, 2020 8:54 pm
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: Cell Diagram
- Replies: 4
- Views: 249
Re: Cell Diagram
yes
- Sun Mar 01, 2020 8:50 pm
- Forum: Balancing Redox Reactions
- Topic: 6L.9
- Replies: 3
- Views: 243
Re: 6L.9
Yeah I think you're right
- Sun Mar 01, 2020 8:46 pm
- Forum: Balancing Redox Reactions
- Topic: Redox Reactions and Acid/Base Reactions
- Replies: 9
- Views: 681
Re: Redox Reactions and Acid/Base Reactions
No they are not
- Sun Feb 16, 2020 8:22 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: K
- Replies: 12
- Views: 643
Re: K
Exclude pure solids and liquids!
- Sun Feb 16, 2020 8:21 pm
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: Delta s = 0
- Replies: 8
- Views: 658
Re: Delta s = 0
In a reversible isothermal reaction
- Sun Feb 16, 2020 8:19 pm
- Forum: Van't Hoff Equation
- Topic: delta s
- Replies: 9
- Views: 546
Re: delta s
Because delta s won't change in those conditions!
- Sun Feb 16, 2020 8:18 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Spontaneous
- Replies: 13
- Views: 739
Re: Spontaneous
When delta G is negative!
- Sun Feb 16, 2020 8:17 pm
- Forum: Phase Changes & Related Calculations
- Topic: Phase changes
- Replies: 8
- Views: 637
Re: Phase changes
Usually when the boiling, melting, or freezing point has been reached.
- Sun Feb 02, 2020 7:47 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Value of q
- Replies: 11
- Views: 534
Re: Value of q
q of the system would be equal to q of the surroundings I believe
- Sun Feb 02, 2020 7:46 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Enthalpy units
- Replies: 5
- Views: 276
Re: Enthalpy units
Typically kj or J
- Sun Feb 02, 2020 7:44 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Test 1 #6
- Replies: 6
- Views: 326
Re: Test 1 #6
HF is a weak acid!
- Sun Feb 02, 2020 7:42 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Moles
- Replies: 8
- Views: 519
Re: Moles
Just the coefficients for gaseous molecules!
- Sun Feb 02, 2020 7:42 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Bond Enthalpies
- Replies: 6
- Views: 372
Re: Bond Enthalpies
Energy is released when the bonds are formed, so it is negative as it is exothermic.
- Sun Jan 26, 2020 11:53 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: delta s
- Replies: 5
- Views: 215
Re: delta s
Delta s is entropy which is change in disorder, while delta h is enthalpy.
- Sun Jan 26, 2020 11:51 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Pure solids & liquids
- Replies: 5
- Views: 322
Re: Pure solids & liquids
Pure solids and liquids are in their pure form and not dissolved in any other liquid.
- Sun Jan 26, 2020 11:50 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Kp to Kc
- Replies: 11
- Views: 529
Re: Kp to Kc
Yes, unless it is a pure solid or gas.
- Sun Jan 26, 2020 11:49 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: H2O as a Gas
- Replies: 69
- Views: 6137
Re: H2O as a Gas
If it is a gas or aqueous you include it, but if not you do not.
- Sun Jan 26, 2020 11:48 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Calculating K
- Replies: 15
- Views: 692
Re: Calculating K
The equation should be balanced.
- Sun Jan 12, 2020 11:09 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Q and K
- Replies: 6
- Views: 374
- Sun Jan 12, 2020 11:08 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Concentrations and the K value.
- Replies: 7
- Views: 380
Re: Concentrations and the K value.
Maybe because it represents the molar ratio of the substances.
- Sun Jan 12, 2020 11:06 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Calculating Q
- Replies: 16
- Views: 700
Re: Calculating Q
You include the aqueous solutions.
- Sun Jan 12, 2020 11:05 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Homogenous Equilibrium
- Replies: 13
- Views: 340
Re: Homogenous Equilibrium
All the products/reactants have to be in the same phase for it to be considered homogeneous.
- Sun Jan 12, 2020 11:04 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Calculating K
- Replies: 9
- Views: 201
Re: Calculating K
Water is not accounted for because it is a pure liquid!
- Thu Dec 06, 2018 11:11 pm
- Forum: Acidity & Basicity Constants and The Conjugate Seesaw
- Topic: H30+ and H+
- Replies: 4
- Views: 599
Re: H30+ and H+
H+ does not usually exist as a single proton and binds with water.
- Thu Dec 06, 2018 11:10 pm
- Forum: Photoelectric Effect
- Topic: Work Function
- Replies: 14
- Views: 2163
Re: Work Function
Use the equation EK = h v - workfunction to solve.
- Thu Dec 06, 2018 11:09 pm
- Forum: Bronsted Acids & Bases
- Topic: Glucose as an acid
- Replies: 3
- Views: 284
Re: Glucose as an acid
I do not think it is either, as well.
- Fri Nov 30, 2018 7:32 am
- Forum: Polarisability of Anions, The Polarizing Power of Cations
- Topic: Polarizability
- Replies: 5
- Views: 417
Re: Polarizability
When it is highly polarizable, this means its electron cloud has a higher chance of being distorted, usually because of the size of the anion.
- Fri Nov 30, 2018 7:31 am
- Forum: Hybridization
- Topic: hybridization notation
- Replies: 3
- Views: 376
Re: hybridization notation
The 2 refers to the energy level of the orbital.
- Fri Nov 30, 2018 7:29 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: bond angle
- Replies: 6
- Views: 485
Re: bond angle
Since you cannot know the exact angle, <120 is acceptable.
- Fri Nov 30, 2018 7:29 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Lone pairs
- Replies: 3
- Views: 433
Re: Lone pairs
Lone pairs have a larger volume of space whereas the electrons on the atoms are more restricted by the bonds so the repulsion is less.
- Fri Nov 30, 2018 7:28 am
- Forum: Sigma & Pi Bonds
- Topic: Sigma bonds
- Replies: 6
- Views: 738
Re: Sigma bonds
Sigma bonds overlap on top of each other.
- Fri Nov 30, 2018 7:27 am
- Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
- Topic: test #3
- Replies: 14
- Views: 1454
Re: test #3
You should know the bond angles. Also, it helps to follow the outlines he posted as to what is on the test.
- Thu Nov 15, 2018 4:52 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: Formal Charge
- Replies: 10
- Views: 1607
Re: Formal Charge
It is important to pay attention to the formal charge as not all elements adhere to the octet rule.
- Thu Nov 15, 2018 4:51 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Double Bonds in VSEPR
- Replies: 5
- Views: 422
Re: Double Bonds in VSEPR
The double bond will still be considered one area of electron density so there is no difference in the model.
- Thu Nov 15, 2018 4:49 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Planar vs Pyramidal
- Replies: 3
- Views: 1418
Re: Planar vs Pyramidal
Even if the atoms are different, it will still be planar.
- Thu Nov 08, 2018 10:09 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: VSEPR
- Replies: 2
- Views: 786
Re: VSEPR
Look at bonding electrons and lone pairs of electrons around the central atom. Sulfur has four bonds and one lone pairs of electrons, so the formula is AX4E which corresponds to the see-saw shape
- Thu Nov 08, 2018 10:06 pm
- Forum: Octet Exceptions
- Topic: Octet vs formal charge
- Replies: 16
- Views: 3055
Re: Octet vs formal charge
It is important to make sure the formal charge is as accurate as possible but always be aware of the octet rule and its exceptions
- Mon Nov 05, 2018 12:56 pm
- Forum: DeBroglie Equation
- Topic: work function and frequency
- Replies: 4
- Views: 876
work function and frequency
How do you calculate the frequency of an incident light when given the wavelength and work function (for example: if the wavelength of the ejected electron is 1.1 nm, what was the frequency of the incident light? The work function of sodium is 150.6 kj mol-1)
- Fri Nov 02, 2018 8:45 am
- Forum: Ionic & Covalent Bonds
- Topic: Ionic vs Covalent Bonds
- Replies: 18
- Views: 1734
Re: Ionic vs Covalent Bonds
Ionic bonds involve the transfer of electrons while in covalent bonds the electron is shared
- Fri Nov 02, 2018 8:43 am
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Degenerate orbitals
- Replies: 3
- Views: 362
Re: Degenerate orbitals
Degenerate orbitals are orbitals that have the same energy level
- Fri Nov 02, 2018 8:39 am
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Is electron removed from 3d or 4s first?
- Replies: 5
- Views: 47961
Re: Is electron removed from 3d or 4s first?
The electron will be removed from 4s first since 3d has slightly higher energy.
- Thu Oct 25, 2018 6:46 pm
- Forum: Properties of Electrons
- Topic: mass of electron
- Replies: 5
- Views: 423
Re: mass of electron
It might be faster when doing calculations to memorize the value, however, most constants and equations can be found on a reference sheet during an exam.
- Thu Oct 25, 2018 6:44 pm
- Forum: Heisenberg Indeterminacy (Uncertainty) Equation
- Topic: Uncertainty of an Electron's Velocity & Speed of Light
- Replies: 4
- Views: 465
Re: Uncertainty of an Electron's Velocity & Speed of Light
Nothing can go faster than the speed of light, so since the model shows the velocity of the electron as being faster, it was disproved.
- Thu Oct 25, 2018 6:27 pm
- Forum: Einstein Equation
- Topic: E=hv [ENDORSED]
- Replies: 52
- Views: 18036
Re: E=hv [ENDORSED]
E represents the energy of the photon but you can also use this equation to find the energy needed to remove the electron, just remember to pay attention to kinetic energy.
- Thu Oct 18, 2018 6:00 pm
- Forum: Photoelectric Effect
- Topic: Speed of Light
- Replies: 5
- Views: 414
Re: Speed of Light
Nothing can travel faster than the speed of light.
- Thu Oct 18, 2018 5:56 pm
- Forum: DeBroglie Equation
- Topic: units
- Replies: 3
- Views: 248
units
When using DeBroglie's equation do you have to calculate given values into certain units before putting them into the equation?
- Thu Oct 18, 2018 5:55 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: orbitals
- Replies: 2
- Views: 264
orbitals
How do you find the number of orbitals in a sub shell when given the value of l?
- Fri Oct 12, 2018 8:24 am
- Forum: SI Units, Unit Conversions
- Topic: Units
- Replies: 8
- Views: 603
Re: Units
I am not sure about points but it is a good idea to write the units in your work just in case and so you know what the correct units should be at the end for your answer
- Fri Oct 12, 2018 8:22 am
- Forum: Significant Figures
- Topic: sig figs urgent question!
- Replies: 12
- Views: 2085
Re: sig figs urgent question!
There are 4 significant figures because the zeros are in between 1s which are sig figs.
- Fri Oct 12, 2018 8:21 am
- Forum: Limiting Reactant Calculations
- Topic: Limiting Reagent
- Replies: 10
- Views: 1558
Re: Limiting Reagent
personally, I would use the amount of each reagant to calculate the amount of moles you have then use the molar ratio to determine how many moles of each substance you need to find the limiting reactant that way.
- Thu Oct 04, 2018 6:29 pm
- Forum: Molarity, Solutions, Dilutions
- Topic: aqueous solutions
- Replies: 1
- Views: 128
aqueous solutions
How do we explain how to prepare an aqueous solution when given the amount we need to prepare and a percent composition of a compound (such as in question G.7 in the sixth edition)?
- Thu Oct 04, 2018 6:25 pm
- Forum: Empirical & Molecular Formulas
- Topic: Molecular Formula
- Replies: 12
- Views: 542
Molecular Formula
How do you write the molecular formula for a compound when given the diagram of the molecular structure? (such as in question F.1 in the sixth edition for example)
- Thu Oct 04, 2018 6:04 pm
- Forum: Empirical & Molecular Formulas
- Topic: Homework Problem F.3 (part a)
- Replies: 2
- Views: 199
Re: Homework Problem F.3 (part a)
There are some common rules you can memorize to help you find the formulas for acids and other compounds. For example, if an acid ends in "ic," it comes from an anion that ended in "ate," in this case nitrate (NO3-). Since the anion has a 1- charge, one hydrogen is needed to bala...