Thermodynamics

Question 1

what happens to density when temperature drops?

Answer 1

density of solution will increase

density is mass/volume
when temperature drops, the container will contract but the mass will stay the same.

Question 2

When an object’s density is less than the solution

Answer 2

the object will float

Question 3

Avogadro’s Law

Answer 3

number of moles is proportional to volume

at constant T and P

Question 4

Charlie’s Law

Answer 4

T proportional to V

at constant P

Question 5

Boyle’s Law

Answer 5

P inversely proportional to V

at constant T

Question 6

Gay-Lussac’s Law

Answer 6

P proportional to T

at constant V

Question 7

Dalton’s Law of Partial Pressure

Answer 7

the partial pressures of the gasses add up to the total pressure

Question 8

How does temperature affect the reaction rate?

Answer 8

increasing temperature will increase the reaction rate because molecules move quicker and collide more often with more energy at higher temperatures

Question 9

temperature and activation energy

Answer 9

higher temperatures make molecules collide more and have more energy which helps overcome the activation energy

Question 10

exothermic reactions

Answer 10

negative delta H

temperature of system and immediate surrounds increase as heat is released

Question 11

endothermic reactions

Answer 11

positive delta H

temperature of system and immediate surroundings decrease as heat is pulled in

Question 12

Hess law

Answer 12

overall enthalpy change delta H of a reaction is equal to the sum of the changes in enthalpy of each component

Question 13

positive entropy

Answer 13

system is more random, less ordered

Question 14

negative entropy

Answer 14

system is more ordered

Question 15

ln(Keq) is positive

Answer 15

delta G is negative and reaction is spontaneous

Keq > 1

Question 16

ln (Keq) is negative

Answer 16

delta G is positive and reaction is nonspontaneous

Keq < 1

Question 17

ln (Keq) = 0

Answer 17

the system is at equilibrium

Keq = 1 –> ln (1) = 0

Question 18

Le Chatelier’s Principle

Answer 18

any changes to a system that moves it away from equilibrium, such as addition of products or reactants, will cause it to adjust accordingly to come back to equilibrium

adding more reactants shifts to products, removing reactants shifts towards reactants

Question 19

adding heat to an endothermic reaction

Answer 19

shifts the equilibrium towards the products

the opposite is true for exothermic reactions

Question 20

higher vapor pressure

Answer 20

weaker intermolecular forces (easier to turn into gas); lower boiling point

takes less heat to reach point of boiling

Question 21

lower vapor pressure

Answer 21

stronger intermolecular forces (harder to turn into gas); higher boiling point

the low pressure requires more heat to reach boiling

Question 22

irreversible reaction

Answer 22

kinetic reaction

forms under low temperatures and moves quickly

the reactions with the lowest activation energy will form fastest and create the most product in a short amount of time

Question 23

reversible reactions

Answer 23

thermodynamic reaction

forms at higher temperatures and moves slowly

whatever has the highest gibbs free energy will make the reaction most stable and will mean that the product is least likely to reversibly change –> therefore would have the most product

Question 24

units of rate

Answer 24

M/s

moles/L*s

Question 25

What will affect the equilibrium constant

Answer 25

only temperature

as temperature increases, the solubility product constant increases for non-gas solutes and decreases for gas solutes