GC2

Question 1

the capacity to do work

Answer 1

energy

Question 2

the study of energy changes in a chemical reaction

Answer 2

Thermochemistry

Question 3

Energy is neither created nor destroyed; it is merely being transformed from one form to another in a chemical reaction.

Answer 3

law of conservation of energy

Question 4

TRUE or FALSE: All forms of energy can be interconverted; however, the total amount of energy through these conversions do not change.

Answer 4

TRUE

Question 5

In the study of thermochemistry, there are two important concepts:

Answer 5

system and surroundings

Question 6

the specific portion of matter that we are interested in.

Answer 6

System

Question 7

is composed of everything in the universe except the system.

Answer 7

surrounding

Question 8

A … separates the system and the surroundings.

Answer 8

boundary

Question 9

Each particle in a system has potential and kinetic energy and the sum of all these energies is … of the system

Answer 9

internal energy (E)

Question 10

TRUE or FALSE: When the reactants in a chemical system change to products, the system’s internal energy has changed.

Answer 10

TRUE

Question 11

A system can change its internal energy in one of two ways:

Answer 11

• By releasing some energy in a transfer to the surroundings
• By absorbing some energy in a transfer from the surroundings

Question 12

Efinal < Einitial

Answer 12

change in E < 0 (release)

Question 13

Efinal > Einitial

Answer 13

change in E > 0 (absorb)

Question 14

Energy transferred from system to surroundings, or vice versa, appears on two forms.

Answer 14

Heat (q) and work (w)

Question 15

Transfer of energy from a body of higher temperature to a body of lower temperature.

Answer 15

Heat (q)

Question 16

Energy transferred when an object is moved by a force.

Answer 16

Work (w)

Question 17

The total change in a system’s internal energy is the sum of the energy transferred as heat and/or as work: formula?

Answer 17

delta E = q + w

Question 18

TRUE or FALSE: The values of q and w can either have a positive or a negative sign. We define the sign of the energy change from the surrounding’s perspective.

Answer 18

FALSE: system’s perspective

Question 19

When heat is released by a system, is the sign of q positive or negative?

Answer 19

-

Question 20

When work is done by a system, is the sign of w positive or negative?

Answer 20

-

Question 21

When heat is absorbed by a system, is the sign of q positive or negative?

Answer 21

+

Question 22

When work is done on a system, is the sign of w positive or negative?

Answer 22

+

Question 23

is an older unit defined originally as the quantity of energy needed to raise the temperature of 1 g of water by 1°C

Answer 23

calorie (cal)

Question 24

1 cal = … J

Answer 24

4.184 J

Question 25

TRUE or FALSE: 1 kcal = 1000 cal = 4184 J

Answer 25

TRUE

Question 26

The two most important types of chemical work are

Answer 26

- electrical work - pressure volume work (PV work)

Question 27

done by moving charged particles

Answer 27

electrical work

Question 28

done when the volume of a system changes in the presence of an external pressure P.

Answer 28

pressure volume work (PV work)

Question 29

The quantity of PV work equals P times the change in volume formula:

Answer 29

w = - P delta V

Question 30

In an open flask (or in a cylinder with a weightless, frictionless piston), a system of an expanding gas does PV work on the surroundings as it pushes against the atmosphere, so the work has a (positive/negative) sign.

Answer 30

-

Question 31

Take note that ΔV is (positive/negative) for a system that is expanding.

Answer 31

positive

Question 32

Since, ΔV is (positive/negative), and the work has a (positive/negative) sign, which means the system has gained energy as work

Answer 32

positive, negative

Question 33

When using the formula, take note that P is usually expressed in ___, and ΔV is expressed in ___, the resulting unit for work when these are used in the formula is ___.

Answer 33

atm, L J

Question 34

1 L*atm = ... J

Answer 34

101.3 J

Question 35

To determine ΔE, we must measure both ___ and ___.

Answer 35

pressure and volume

Question 36

a thermodynamic quantity called ..., eliminates the need to measure PV work.

Answer 36

enthalpy (H)

Question 37

The enthalpy of a system is defined as the internal energy plus the product of the pressure and volume formula:

Answer 37

H = E + PV

Question 38

The change in enthalpy (ΔH) is the change in the system’s internal energy plus the product of the pressure, which is constant, and the change in volume (ΔV) formula:

Answer 38

ΔH = ΔE + PΔV ΔH = (q + W) + PΔV

Question 39

constant pressure the formula for ΔH simplifies to

Answer 39

ΔH = qp

Question 40

An exothermic process releases heat and results in a/n (increase/decrease) in the enthalpy of the system On which side of the equation will heat appear: reactant or product? What is the sign of ΔH?

Answer 40

decrease, product side, negative

Question 41

An endothermic process absorbs heat and results in a/n (increase/decrease) in the enthalpy of the system. On which side of the equation will heat appear: reactant or product? What is the sign of ΔH?

Answer 41

increase, reactant side, positive

Question 42

a balanced equation that includes the enthalpy change of the reaction (ΔH).

Answer 42

thermochemical equation

Question 43

TRUE or FALSE: ΔH refers only to the amounts (mol) of substances and their states of matter in that equation.

Answer 43

true

Question 44

The enthalpy change of any process has two aspects:

Answer 44

sign and magnitude

Question 45

TRUE or FALSE: The magnitude of ΔH depends on whether the reaction is exothermic (-) or endothermic (+).

Answer 45

FALSE: sign

Question 46

TRUE or FALSE: A forward reaction has the opposite sign of the reverse reaction.

Answer 46

TRUE

Question 47

TRUE or FALSE: The magnitude of ΔH is proportional to the amount of substance.

Answer 47

TRUE

Question 48

the enthalpy change of an overall process is the sum of the enthalpy changes of its individual steps.

Answer 48

Hess's law

Question 49

How to adjust equation?

Answer 49

- Reverse - Multiply or Divide