Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Chemistry 30 > Thermochemistry > Flashcards

Thermochemistry Flashcards

You may prefer our related Brainscape-certified flashcards:
Chemistry 101 flashcards Periodic Table flashcards AP® Chemistry flashcards Organic Chemistry 101 flashcards
1
Q

Thermochemistry:

A

The study of heat changes associated with physical, chemical and nuclear processes.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Potential Energy:

A

Stored energy.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Kinetic Energy:

A

The energy of motion.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Exothermic Processes:

A

Energy is released to its surroundings. It is mathematically negative.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Endothermic Processes:

A

Energy is absorbed from its surroundings. It is mathematically positive.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

If energy is a reactant it is ___________.

A

endothermic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

If energy is a product it is __________.

A

exothermic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Photosynthesis is (endo/exo)thermic.

A

endo

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Cellular respiration is (endo/exo)thermic

A

exo

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is total enthalpy affected by?

A

Molecular structure of the substance and the mass of the substance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are the units for enthalpy?

A

kJ

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are the units for molar enthalpy?

A

kJ/mol

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Describe the endothermic chemical reaction.

A

Bonds of the reactants are broken and energy is required.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Describe the exothermic chemical reaction.

A

Bonds of the products are reformed and energy is released.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Does an exothermic visual diagram start high or low?

A

High.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Does an endothermic visual diagram start high or low?

A

Low.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is the bump in a reaction diagram?

A

Activation energy.

18
Q

What is necessary for a reaction diagram?

A

Title, labelled axis’, enthalpy change, reactants and products, units.

19
Q

What three things affect kinetic energy?

A

Temperature, amount, and type of substance.

20
Q

How do you calculate Ek?

A

mc(change in)t

21
Q

How do you calculate molar enthalpy?

A

Ep/n

22
Q

What are the units for specific heat capacity?

A

J/gC

23
Q

Specific heat capacity:

A

The amount of heat energy needed to raise the temperature of 1 g of a substance 1C/1K

24
Q

Which has a higher heat capacity, metal or rubber?

A

Rubber

25
Q

When Ek is negative, a substance is _______ ____.

A

cooling down

26
Q

When Ek is positive, a substance is _______ ____.

A

heating up

27
Q

How do you do calorimetry with a styrofoam calorimeter?

A

Calculate Ek, multiply by -1 to get Ep, Ep/n

28
Q

What has a 1:1 ratio with 1g?

A

1 mL

29
Q

How do you do calorimetry with a metal can calorimeter?

A

Ek = mct(water) + mct(can), * -1 = Ep, Ep/n

30
Q

When in a combustion reaction is water a liquid?

A

In a bomb calorimeter or a living system ie. human urine

31
Q

When in a combustion reaction is water gas?

A

In an open environment ie. boiling a pot of water

32
Q

What are the Molar Enthalpy of Formation values derived from?

A

Bomb calorimeter data.

33
Q

Commonly, molar enthalpy of formation reactions are (end/ex)othermic.

A

end

34
Q

How do you find the molar enthalpy of a decomposition?

A

Flip the sign from the data booklet.

35
Q

What is the molar enthalpy of formation for elements assumed to be?

A

Zero.

36
Q

When Ep is released in formation, what is the result?

A

A more thermally stable compound.

37
Q

Which is more thermally stable and why?
SO3(l) H = -441.0 kJ
SO3(g) H = -395.7 kJ

A

The liquid one because more Ep was released.

38
Q

Catalysts:

A

Can be used to speed up reactions that are exothermic but react slowly. They reduce the activation energy required to move the reaction forward. (They provide an alternate reaction path.)

39
Q

When a catalyst is added, does the Molar Enthalpy of Formation/Decomposition value change?

A

No.

40
Q

Which compound is more thermally stable, glucose or sucrose?

A

Sucrose.

41
Q

Basic rules to apply to Hess’s law:

A
  1. Balanced equation with molar enthalpy
  2. Decompose one mole of each reactant and change the enthalpy sign. Multiply enthalpy by coefficients
  3. Form the correct number of moles for the products and multiply by coefficients
  4. Ignore elements as they will typically sort themselves out
  5. Add the equations, and they should add up to the original equation.
42
Q

How do you use Hess’s Law Shortcut?

A
  1. Write a balanced equation for which H is needed for one mol
  2. Add all the H values of the compounds on the products side
  3. Add all the H values on the reactant side
  4. Multiply H values by coefficients if needed
  5. Subtract the sum of the reactants from the sum of the products

Chemistry 30 (4 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions