Ch. 10 Energy

Question 1

Energy

Answer 1

The ability to do something

Question 2

Potential Energy

Answer 2

1. Stored energy, waiting to be used

2. Depends on height

Question 3

Kinetic Energy

Answer 3

1. Energy in use

2. Converted from potential energy

Question 4

Law of Conservation of Energy

Answer 4

Energy is neither created nor destroyed

Question 5

State Function

Answer 5

A change that occurs that is independent of the pathway taken
Ex: Change in elevation

Question 6

Temperature

Answer 6

Measure of the randomness in the movement of particles

Question 7

Heat

Answer 7

1. Flow of energy as temperature changes

2. Flows from hot to cold

Question 8

System

Answer 8

Focal point

Question 9

Surroundings

Answer 9

The thing going on around the system

Question 10

Exothermic

Answer 10

Energy being released

Question 11

Endothermic

Answer 11

Energy being absorbed

Question 12

&E = q + w

Answer 12

1. Change in energy = heat + work

2. Heat and work have both a sign and a magnitude

Question 13

1 Cal = ? Joules

Answer 13

1 cal = 4.184 J

Also the specific heat of water

Question 14

q = cm&t

Answer 14

heat = specific heat capacity (mass) (change in temperature)

Question 15

Specific Heat Capacity

Answer 15

Amount of heat you need to raise 1 gram of something 1 degree Celsius

Question 16

A 5.63 g sample of solid gold is heated from 21 C to 32 C. How much energy (J and cal) is required?

Answer 16

C= 0.13
q = (.13)(5.63)(21) = 15 J
15 J (1 cal / 4.184 J) = 3.6 J

Question 17

When 1 mol of methane is burned at constant pressure; 890 kJ of energy is released as heat. Calculate &H for a process in which a 5.8g sample of methane is burned at constant pressure.

Answer 17

5.8 g CH4 ( 1 mol/16.05) = .36 mol CH4

.36 mol CH4 (890 kJ/1 mol) = -320 kJ (released)

Question 18

What are the steps/rules for a Hess’ Law Equation?

Answer 18

1. Look at the equations
2. Ask “what needs to be a reactant?”
3. Ask “what needs to be a product?”
4. Reverse an equation that needs to be switched around by multiplying by a negative number
5. Things that are exactly the same on both sides of equations can cancel out
6. Can multiply by different numbers to get the correct coefficient
7. Combine the &H’s

Question 19

Enthalpy

Answer 19

Is equal to the energy flow as heat

Question 20

What is the driving force for every exothermic process?

Answer 20

Entropy (degree of disorder/energy spread)

Question 21

A gas releases 25.9 J of heat and has 99 J of work done on it. Calculate &E

Answer 21

&E = q + w
&E = (-)25.9 + 99
&E = +73.1