Unit 1: Energy

Question 1

Exothermic Energy Change

Answer 1

• Temp of the surroundings will increase.
• The Energy is exiting the system and into the surroundings. (exo = exit)
• More kinetic energy
• (-) Enthalphy Change

Question 2

Endothermic Energy Change

Answer 2

• Temp of the surroudings will decrease
• The energy from the surroundings is being absorbed into the system.
• Meaning it stores that energy.
• More potential energy
• (+) Enthalphy Change

Question 3

Difference between Temperature and Heat

Answer 3

• Heat is energy gaines or lost
• Temperature is the measurement of the avg
  kinetic energy

Question 4

1st Law of Thermodynamics

Answer 4

• Energy can only be transffered.
• Cant create or destroy

Question 5

2nd law of thermodynamics

Answer 5

• Heat from a high temp object will keep transferring to a low temp object UNTIL they are the same temperature.

Question 6

What is Enthalpy Change?

Answer 6

• All. Total Energy of system
• Total energy absorbed (+) or released (-) by the system.

Question 7

What is Molar Enthalphy?

Answer 7

• Specific. Enthalphy that happens for 1 mol of that substance

Question 8

How to write a Thermochemical Equation?

Answer 8

• Write the chemical reaction
• Balance
• Use the molar enthalphy of a compound to find the enthalphy change
• Determine if its exo or endo.

Endo:Energy is at the left(stored)
Exo:Energy is at the right(released)

Question 9

If the reactants are higher in potential energy.
What potentional energy diagram is it?

Answer 9

Exothermic.
The reactants release the energy into kinetic.

Question 10

If the products are higher in potential energy.
What potentional energy diagram is it?

Answer 10

Endothermic. The products absorbed energy.

Question 11

Collision Theory

Answer 11

• Reactant particles collide for a reaction to happen.

Question 12

Conditions for Collision Theory in order to form products

Answer 12

• Right orientation during impact
• Collision energy needed (activation energy)

Question 13

What is a Catalyst?

Answer 13

• Increases the rate of chemical reaction
• Decreases activation energy
• Doesnt change enthaply
• Doesn’t get used up.

Question 14

What is an Activation Complex?

Answer 14

• A transition state where the molecules don’t have bonds. (Peak of the graph)

Question 15

What is an open, closed, isolated system?

Answer 15

• Open: matter and energy can leave or go in
• Closed: Matter can’t leave or go in, but energy can
• Isolated: Nothing leaves or goes in.

Question 16

What is Calorimetry?

Answer 16

• Measuring heat released or absorbed using an isolated system called “calorimeter”.

Question 17

What are the assumptions for calorimetry?

Answer 17

• It’s an isolated system. So nothing leaves or goes in
• The device to measure, calorimeter, doesnt absorb heat
• The thing being studied is surrouned by a little bit of water and a stable specific heat capacity.

Question 18

What’s a bomb calorimeter?

Answer 18

• It’s a closed system

Question 19

Why does calorimetry work?

Answer 19

• Because of the 1st and 2nd law of thermodynamics. (What are they huh?)

Question 20

What are the Diatomic Elements?

Answer 20

• N2, O2, F2, Cl2, Br2, I2, At2

Question 21

What are the Polyatomic Elements?

Answer 21

• P4, S8, O3 (ozone)

Question 22

Good Practices Questions for Review
from 1-32.

Answer 22

Questions: 3, 5, 7, 8, 15, 18, 24, 31, 32, 33, 34, 35, 40, 42, 43, 45, 46, 54, 57, 58, 59, 63, 64.

Question 23

-/+ temperature change

Answer 23

• If the temp change is (-), Then its endothermic because the temp decreased so the surroudings cooled down.
• If the temp change is (+), Then its exothermic because the temp increased so the surroudings heated up,

Questions good for this: 60

Question 24

Unit Conversions
kg -> g
L -> ml

Answer 24

1kg = 1000g
1L = 1000ml
1L = 1kg
1ml = 1g

Questions good for this: 72

Question 25

How to figure out which one is negative in the reaction

Answer 25

- If the temp change is (-), then water is negative - If the temp change is (+), then water is positive (If the calorimeter is a metal then the symbol is the same as the water cause theyre together) | Questions good for this: 57

Question 26

Steps in solving a problem that has a metal calorimeter.

Answer 26

1. Get the mass, heat capacity, of the water and metal calorimeter 2. Use the same temp change for both 3. Use the water and metal calorimeter to find the ( kj ) 4. Use the other thing to find the mol | Questions good for this: 60, 61

Question 27

Steps in doing neutralizaion calorimetry

Answer 27

1. Find what which one we neutralization we looking for. 2. Turn their ml into L 3. Find the moles by using n= C * V 4. Now just do a simple q=mcΔt for both and add them together 5. Divide by the mol 6. For the thermochemical equation, the arrow is an equilibrium arrow | Questions good for this: Example question page 35 ## Footnote C is concentration V is volume n is moles

Question 28

Cellular Respiration

Answer 28

- Exothermic - --> CO2(g) + H2O(l) + ATP | The important bit is that the water is liquid.

Question 29

Photosynthesis

Answer 29

- Endothermic - sunlight + CO2(g) + H2O(l) --> | Water is liquid state

Question 30

What is the original source of energy in fossil fuels?

Answer 30

- THE SUN

Question 31

Finding the molar enthalphy change without any mass or anything

Answer 31

1. Write the equation and balance it 2. List all of the molar enthalphy of each compound 3. Find the enthalphy change by doing [ final - initial ] 4. Divide by the moles of the thing you are looking for | Questions good for this: 86, 88

Question 32

Formula for Efficiency and Percent error

Answer 32

actual/experimental ------------------------------ x100 predicted/stored/theoritical

Question 33

Thermal Stability

Answer 33

- Get the molar enthalphy for the decomposition - Compare and see which one is highest (positvely high)