Search found 29 matches
- Wed Feb 19, 2020 4:38 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Equilibrium
- Replies: 15
- Views: 218
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.
- Wed Feb 19, 2020 4:37 pm
- Forum: Balancing Redox Reactions
- Topic: Reduction vs. oxidation
- Replies: 29
- Views: 354
Re: Reduction vs. oxidation
Oxidation is when electrons are lost while reduction is when electrons are gained.
- Wed Feb 19, 2020 4:33 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Salt Bridge
- Replies: 4
- Views: 60
Re: Salt Bridge
The salt bridge is in charge of the transfer of electrons.
- Wed Feb 19, 2020 4:32 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Sign of delta G
- Replies: 9
- Views: 198
Re: Sign of delta G
Yes, if you have enough information you should be able to use the values of Q and K.
- Wed Feb 19, 2020 4:31 pm
- Forum: Balancing Redox Reactions
- Topic: Balancing half reactions
- Replies: 11
- Views: 145
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.
- Sat Feb 08, 2020 1:57 pm
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: Positive ∆S
- Replies: 5
- Views: 90
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.
- Sat Feb 08, 2020 1:54 pm
- Forum: Phase Changes & Related Calculations
- Topic: phase changes, temperature constant?
- Replies: 11
- Views: 196
Re: phase changes, temperature constant?
Temperature remains constant during phase change because heat energy is stored as potential energy.
- Sat Feb 08, 2020 1:49 pm
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: Entropy + Disorder
- Replies: 3
- Views: 60
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.
- Sat Feb 08, 2020 1:43 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: Endothermic vs Exothermic
- Replies: 10
- Views: 216
Re: Endothermic vs Exothermic
Gaining heat would result in a positive q value whereas releasing heat would result in a negative q value.
- Sat Feb 08, 2020 1:42 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Closed Systems
- Replies: 13
- Views: 154
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.
- Sat Feb 08, 2020 1:40 pm
- Forum: Ideal Gases
- Topic: Compressing a gas
- Replies: 5
- Views: 102
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.
- Sat Feb 08, 2020 1:37 pm
- Forum: Calculating Work of Expansion
- Topic: Isothermal
- Replies: 17
- Views: 198
Re: Isothermal
An isothermal process is a change of system where the temperature remains constant. Therefore, delta U would be equal to 0.
- Sat Feb 08, 2020 1:35 pm
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: Entropy
- Replies: 3
- Views: 56
Re: Entropy
Entropy is a state function since they describe quantitatively an equilibrium state of a thermodynamic system.
- Thu Jan 30, 2020 9:55 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: 4A.1
- Replies: 12
- Views: 81
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.
An isolated system can neither exchange matter nor energy with the surroundings.
- 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: 107
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.
- Thu Jan 30, 2020 6:31 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Constant Pressure
- Replies: 7
- Views: 89
Re: Constant Pressure
This tells you that the values of pressure and volume would not change.
- Wed Jan 22, 2020 3:36 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: 6D 13
- Replies: 1
- Views: 54
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...
- Thu Jan 16, 2020 8:38 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Weak and strong acids/bases
- Replies: 2
- Views: 27
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.
- 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: 114
Re: Endo/Exothermic Reactions
This would vary depending on the situation, such as the overall heat change of the system.
- Thu Jan 16, 2020 8:33 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: ICE and quadratic formula
- Replies: 11
- Views: 107
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.
- 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: 85
Re: Endothermic and exothermic
Endothermic includes absorbing heat and breaking bonds.
Exothermic includes releasing heat and forming bonds.
Exothermic includes releasing heat and forming bonds.
- 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: 55
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.
- Thu Jan 09, 2020 5:13 pm
- Forum: Ideal Gases
- Topic: K based on phases
- Replies: 4
- Views: 72
Re: K based on phases
Pure solids and liquids are not considered when calculating the equilibrium constant.
- Thu Jan 09, 2020 5:10 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Pressure
- Replies: 4
- Views: 58
Re: Pressure
Change in pressure does not affect the equilibrium act it does not react with anything in the reaction.
- Wed Jan 08, 2020 10:38 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Increasing volume
- Replies: 5
- Views: 411
Re: Increasing volume
Yes. When the volume of reaction is increased, K will shift to the side with more moles.
- 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: 104
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.
- Mon Jan 06, 2020 7:49 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Reactant Quotient vs Equilibrium Constant
- Replies: 3
- Views: 65
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.
- 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?
- Mon Jan 06, 2020 7:36 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: 5G.3
- Replies: 8
- Views: 125
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...