Search found 29 matches

by Jessica Kwek 4F
Wed Feb 19, 2020 4:38 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Equilibrium
Replies: 15
Views: 137

Re: Equilibrium

At equilibrium, delta G would be 0 since the reactants and products are occurring at the same rate, which means that the reaction favors neither side.
by Jessica Kwek 4F
Wed Feb 19, 2020 4:37 pm
Forum: Balancing Redox Reactions
Topic: Reduction vs. oxidation
Replies: 29
Views: 262

Re: Reduction vs. oxidation

Oxidation is when electrons are lost while reduction is when electrons are gained.
by Jessica Kwek 4F
Wed Feb 19, 2020 4:33 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Salt Bridge
Replies: 4
Views: 31

Re: Salt Bridge

The salt bridge is in charge of the transfer of electrons.
by Jessica Kwek 4F
Wed Feb 19, 2020 4:32 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Sign of delta G
Replies: 9
Views: 127

Re: Sign of delta G

Yes, if you have enough information you should be able to use the values of Q and K.
by Jessica Kwek 4F
Wed Feb 19, 2020 4:31 pm
Forum: Balancing Redox Reactions
Topic: Balancing half reactions
Replies: 11
Views: 90

Re: Balancing half reactions

When balancing half reactions, make sure that your electrons cancel out. They would cancel as long as the number of electrons on both sides are equal to each other.
by Jessica Kwek 4F
Sat Feb 08, 2020 1:57 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Positive ∆S
Replies: 5
Views: 56

Re: Positive ∆S

Positive delta S is not information to determine whether the reaction is spontaneous or not. You would need to look at the over Gibbs Free Energy equation.
by Jessica Kwek 4F
Sat Feb 08, 2020 1:54 pm
Forum: Phase Changes & Related Calculations
Topic: phase changes, temperature constant?
Replies: 11
Views: 130

Re: phase changes, temperature constant?

Temperature remains constant during phase change because heat energy is stored as potential energy.
by Jessica Kwek 4F
Sat Feb 08, 2020 1:49 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Entropy + Disorder
Replies: 3
Views: 29

Re: Entropy + Disorder

Entropy is used to describe the randomness and therefore disorder of molecules in the given reaction/system. It measures the number of possible arrangements the atoms in the system could have.
by Jessica Kwek 4F
Sat Feb 08, 2020 1:43 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Endothermic vs Exothermic
Replies: 10
Views: 168

Re: Endothermic vs Exothermic

Gaining heat would result in a positive q value whereas releasing heat would result in a negative q value.
by Jessica Kwek 4F
Sat Feb 08, 2020 1:42 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Closed Systems
Replies: 13
Views: 106

Re: Closed Systems

A closed system can only be changed by temperature, pressure, or volume. In a closed system, neither reactants or products can enter or escape, but the transfer of energy is allowed.
by Jessica Kwek 4F
Sat Feb 08, 2020 1:40 pm
Forum: Ideal Gases
Topic: Compressing a gas
Replies: 5
Views: 73

Re: Compressing a gas

After compressing a gas, the reaction would favor the side with less moles of gas because this reduces the number of particles in the gas. Volume and pressure have an inverse relationship.
by Jessica Kwek 4F
Sat Feb 08, 2020 1:37 pm
Forum: Calculating Work of Expansion
Topic: Isothermal
Replies: 17
Views: 164

Re: Isothermal

An isothermal process is a change of system where the temperature remains constant. Therefore, delta U would be equal to 0.
by Jessica Kwek 4F
Sat Feb 08, 2020 1:35 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Entropy
Replies: 3
Views: 33

Re: Entropy

Entropy is a state function since they describe quantitatively an equilibrium state of a thermodynamic system.
by Jessica Kwek 4F
Thu Jan 30, 2020 9:55 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: 4A.1
Replies: 12
Views: 69

Re: 4A.1

A closed system has a fixed amount of matter, but it can only exchange energy with the surroundings.
An isolated system can neither exchange matter nor energy with the surroundings.
by Jessica Kwek 4F
Thu Jan 30, 2020 6:34 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: reaction enthalpy
Replies: 14
Views: 91

Re: reaction enthalpy

It requires energy to be inputted in order to break bonds, which is why breaking bonds makes enthalpy positive. Therefore, forming bonds would make enthalpy negative.
by Jessica Kwek 4F
Thu Jan 30, 2020 6:31 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Constant Pressure
Replies: 7
Views: 70

Re: Constant Pressure

This tells you that the values of pressure and volume would not change.
by Jessica Kwek 4F
Wed Jan 22, 2020 3:36 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 6D 13
Replies: 1
Views: 37

6D 13

Question: Rank the following solutions in order of increasing pH: (a) 1.0 3 1025 m HCl(aq); (b) 0.20 m CH3NH3Cl(aq); (c) 0.20 m CH3COOH(aq); (d) 0.20 m C6H5NH2(aq). Justify your ranking. How do we calculate the pH of the weak acid/bases using an ice table? I am confused on part b since CH3NH3Cl is a...
by Jessica Kwek 4F
Thu Jan 16, 2020 8:38 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Weak and strong acids/bases
Replies: 2
Views: 22

Re: Weak and strong acids/bases

Regarding calculations, you usually have to use an ICE table for weak acids and weak bases since they do not dissociate completely. An ICE table is not needed when doing calculations for strong acids and strong bases.
by Jessica Kwek 4F
Thu Jan 16, 2020 8:36 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Endo/Exothermic Reactions
Replies: 6
Views: 73

Re: Endo/Exothermic Reactions

This would vary depending on the situation, such as the overall heat change of the system.
by Jessica Kwek 4F
Thu Jan 16, 2020 8:33 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: ICE and quadratic formula
Replies: 11
Views: 94

Re: ICE and quadratic formula

You are able to skip the ICE table when K is less than 10^-3. If K is greater than 10^-3, you have to use the quadratic formula to solve for x.
by Jessica Kwek 4F
Thu Jan 16, 2020 8:31 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Endothermic and exothermic
Replies: 5
Views: 53

Re: Endothermic and exothermic

Endothermic includes absorbing heat and breaking bonds.
Exothermic includes releasing heat and forming bonds.
by Jessica Kwek 4F
Tue Jan 14, 2020 10:46 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: 5.33
Replies: 6
Views: 43

Re: 5.33

Since the chemical reaction is endothermic, increasing the temperature would shift the reaction to the product side. Therefore, it would increase the formation of X.
by Jessica Kwek 4F
Thu Jan 09, 2020 5:13 pm
Forum: Ideal Gases
Topic: K based on phases
Replies: 4
Views: 49

Re: K based on phases

Pure solids and liquids are not considered when calculating the equilibrium constant.
by Jessica Kwek 4F
Thu Jan 09, 2020 5:10 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Pressure
Replies: 4
Views: 55

Re: Pressure

Change in pressure does not affect the equilibrium act it does not react with anything in the reaction.
by Jessica Kwek 4F
Wed Jan 08, 2020 10:38 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Increasing volume
Replies: 5
Views: 346

Re: Increasing volume

Yes. When the volume of reaction is increased, K will shift to the side with more moles.
by Jessica Kwek 4F
Wed Jan 08, 2020 10:31 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Pressure's Effect on Equilibrium
Replies: 6
Views: 101

Re: Pressure's Effect on Equilibrium

The equilibrium constant does not change when pressure is increased by adding an inert gas because it does not react with anything in the reaction. The concentration of each reactant are not changed. The system will still be at equilibrium, which leaves K to remain the same.
by Jessica Kwek 4F
Mon Jan 06, 2020 7:49 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Reactant Quotient vs Equilibrium Constant
Replies: 3
Views: 58

Re: Reactant Quotient vs Equilibrium Constant

You would calculate the reactant quotient the same way that you calculate the equilibrium constant. You solve for the reactant quotient when the reaction is not at equilibrium. The equilibrium constant is calculated when the reaction is at equilibrium.
by Jessica Kwek 4F
Mon Jan 06, 2020 7:41 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 5l.7
Replies: 1
Views: 40

5l.7

For 5l.7, the question asks whether the reaction will have a tendency to form products or reactants at equilibrium where it is given that Q=1. How do we find the value of K for the reaction to compare it to Q?
by Jessica Kwek 4F
Mon Jan 06, 2020 7:36 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 5G.3
Replies: 8
Views: 106

Re: 5G.3

K is written in terms of partial pressures since the reactants and products for both reactions all in gas phase. This means that you would write the expression for the equilibrium constant K as a formula for Kp. This includes the partial pressure of the product in the numerator, raised to a power eq...

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