Reaction Energy

Question 1

What is a Calorimeter?

Answer 1

a device that measures the change in energy (temperature)
- can also measure the average kinetic energy in a sample of matter

Question 2

Fill in the blanks with hotter/colder

Heat always moves from ____ matter to ____ matter

Answer 2

from HOTTER matter to COLDER matter

Question 3

What does Q stand for in the equation:

Q = mc ΔT

Answer 3

Energy ( J )

Question 4

What does m stand for in the equation:

Q = mc ΔT

Answer 4

mass ( g )

Question 5

What does c stand for in the equation:

Q = mc ΔT

Answer 5

specific heat

Question 6

What does ΔT stand for in the equation:

Q = mc ΔT

Answer 6

temperature ( Celsius )

Question 7

What is Enthalpy?

Answer 7

Heat energy transferred during a chemical equation
- called “heat of reaction”

Question 8

What is the symbol for Enthalpy?

Answer 8

ΔH

Question 9

Is ΔH positive or negative in an exothermic equation?

Answer 9

negative

Question 10

which side is heat on during an exothermic reaction?

Answer 10

the product side

Question 11

Is ΔH positive or negative during an endothermic reaction?

Answer 11

positive

Question 12

Which side is heat on during an endothermic reaction?

Answer 12

reactant side

Question 13

What are four things you should always consider in a thermochemical equation?

Answer 13

1. coefficients
2. the physical state (ex. solid, liquid, gas)
3. the change in enthalpy
4. the value of ΔH

Question 14

Is an exothermic reaction stable or unstable?

Answer 14

stable

Question 15

Is the ΔH value positive or negative during a stable reaction?

Answer 15

negative

Question 16

Is an endothermic reaction stable or unstable?

Answer 16

unstable

Question 17

Is the ΔH value positive or negative during an unstable reaction?

Answer 17

positive

Question 18

Do you want ΔH to be positive or negative?

Answer 18

negative

Question 19

What is Hess’s Law?

Answer 19

calculating the total ΔH from individual steps

Question 20

What is the formula for ΔH

Answer 20

ΔH = Reactants - products

Question 21

What do you have to draw in order to show the bond energies?

Answer 21

lewis structures

Question 22

What does entropy measure?

Answer 22

entropy measures the randomness in a system.

Question 23

What is the symbol for Entropy?

Answer 23

ΔS

Question 24

What does ΔG stand for in the equation:

ΔG = ΔH - TΔS

Answer 24

available energy

Question 25

What does ΔH stand for in the equation:

ΔG = ΔH - TΔS

Answer 25

Enthalpy change

Question 26

What does T stand for in the equation:

ΔG = ΔH - TΔS

Answer 26

Temperature in Kelvin

Question 27

What does ΔS stand for in the equation:

ΔG = ΔH - TΔS

Answer 27

entropy change

Question 28

What is a Catalyst?

Answer 28

starts as a reactant and ends as a product

Question 29

What is an intermediate

Answer 29

starts as a product and ends as a reactant

Question 30

What are the four parts of the Collision Theory?

Answer 30

1. Reactions must have the “right order” to react
2. molecules must collide to react
3. they must collide with the correct orientation
4. they must collide with enough energy to overcome electron - electron repulsion

Question 31

does an endothermic reaction break or form bonds

Answer 31

breaks

Question 32

does an exothermic reaction break or form bonds

Answer 32

form

Question 33

What are the 5 factors that affect the reaction rate of a reaction?

Answer 33

1. state of matter
2. temperature
3. surface area
4. concentration
5. catalyst