Unit 2: Thermochemistry

Question 1

What is a general definition for Thermochemistry?

Answer 1

Energy changes associated w/ chemical reactions.

Question 2

Is bond forming exothermic/endothermic? What about bond breaking?

Answer 2

Bond forming is exothermic; bond breaking is endothermic.

Question 3

Define Heat

Answer 3

The transfer of kinetic energy from one body of mass to another.

Question 4

Define Temperature

Answer 4

Average Kinetic Energy

Question 5

Heat goes from a _____ object to a _____ object.

Answer 5

Warm-Cold

Question 6

Define Conduction

Answer 6

Heat transfer through the collision of particles.

Question 7

1J is the energy needed to _____.

Answer 7

Exert a force of 1N over 1 meter.

Question 8

What is the equation for Force?

Answer 8

Mass x Acceleration

Question 9

What are the units for newtons?

Answer 9

kg.m/ sec^2

Question 10

What happens, in detail, when there’s an exothermic reaction?

Answer 10

It will physically interact with the surrounding molecules, will increase the KE of surrounding molecules, increase in heat, increase in temperature.

Question 11

Enthalpy is associated with _____.

Answer 11

The heat change of a chemical reaction.

Question 12

Define State Function

Answer 12

Variable that depends only on the initial and final state; it is a path independent variable.

Question 13

What is an example of a state function and what is not?

Answer 13

Example: Total Energy Change
Not An Example: Work

Question 14

What is the equation for Work?

Answer 14

Force x Distance

Question 15

Is potential energy a state function?

Answer 15

Yes

Question 16

What is the equation for Total Energy Change?

Answer 16

Total Energy Change= Heat Energy + Work ; Delta E Rxn= Q rxn +PDeltaV

Question 17

What is the equation for Enthalpy?

Answer 17

Delta H Rxn= Heat at Constant Pressure

Question 18

How does bond breaking in ATP release energy?

Answer 18

In ATP reaction w/ water, a new bond is formed. In the hydrolysis reaction, the water reacts with one of the phosphate groups, replacing one of the P-O bonds w/ a P-OH bond. Furthermore, H+ is formed in aqueous solution (would be present as H3O+). The new bond formation would provide the exothermic character of the reaction.

Question 19

What is the first law of thermodynamics?

Answer 19

Conservation of energy (the energy released by a reaction is equal to the energy absorbed by the surroundings). Delta E Reaction= (-) Delta E Surroundings.

Question 20

What is another name for Coffee Cup Calorimetry?

Answer 20

Constant Pressure Calorimetry

Question 21

What is the purpose of a Styrofoam cup in Coffee Cup Calorimetry?

Answer 21

They’re used to prevent the escape of heat/absorption of heat from the outside.

Question 22

What is an important equation to remember for Coffee Cup Calorimetry?

Answer 22

Q H2O= (-) Q RXN CW (Coffee-Cup/ Water)

Question 23

What is an important thing to remember for Bomb Calorimetry?

Answer 23

Q RXN= (-) Q H2O

Question 24

Enthalpy changes are _____.

Answer 24

Path Independent

Question 25

What does Standard Enthalpy of Formation entail?

Answer 25

Means we’re synthesizing a molecule from its most stable constituents.

Question 26

What is the equation for the Standard Enthalpies of Formation?

Answer 26

Sum of the Moles of Products- Sum of the Moles of Reactants

Question 27

What is the equation for the Bond Dissociation Energies of a reaction?

Answer 27

Sum of the Moles of the Reactants- Sum of the Moles of Products

Question 28

How can Bond Dissociation Energy be defined as?

Answer 28

The amount of energy required to break the common bonds that have been determined experimentally.

Question 29

Define Enthalpy

Answer 29

The heat that is being absorbed or released during the progression of a chemical reaction.

Question 30

What is the equation for work?

Answer 30

Work= -PDeltaV (Assuming Constant Pressure)