Chemistry 121 Test 4

Question 1

K.E.

Answer 1

= 1 /2 mass x (speed)²

Question 2

1J

Answer 2

1.kg · m²/s²

Question 3

Heat

Answer 3

Q

Average kinetic energy posessed by atoms and molecules due to their motions.

Question 4

Temperature

Answer 4

T

A proportional measure of heat

sometimes refered to as kT or RT

Question 5

Internal Energy:

Translation

Answer 5

Motion in a straight line

Question 6

Internal Energy:

Rotation

Answer 6

motion about an axis of symmetry

(water at 25°C, 1 ATM → speed 330m/s)

Question 7

Internal energy:

Vibration

Answer 7

atoms stretch back and forth in relation to eachother

10^12-13/s

Question 8

Internal Energy

Answer 8

E = E_trans+ E_rot + E_vib

Question 9

Closed System

Answer 9

the amount of matter is fixed but heat may be added or removed

Question 10

Q

Answer 10

-Ask Olivia-

= heat

• heat added to a system (+) endothermic
• heat removed from a system (-) exothermic

Question 11

If the change in internal energy, ∆E, is +

Answer 11

then heat was added to the system +

work done on the system +

Question 12

∆H = +

Answer 12

Edothermic process.

Heat is required for the process/reaction to proceed.

Question 13

∆H = -

Answer 13

Exothermic process.

Heat is released.

Question 14

∆H =

Answer 14

∆H = Σ∆Hº_{f products} - Σ∆Hº_{f reactants}

Question 15

∆Hº_f is defined as…

Answer 15

The Enthalpy change which accompanies the formation of one mole of a substance (usually a compound) from it’s elements in their most stable states @ 25ºC 1 ATM.

Question 16

∆ in anything is…

Answer 16

final - initial

Temperature, Volume etc.

Question 17

The nature of everything is to have minimal Enthalpy.

Answer 17

∆H = - ? favored

∆H = + ? unfavored

Question 18

Specific Heat

Answer 18

The quantity of heat (J) necessary to raise the temperature of 1 gram of a substance by 1ºC.

*Units are J/g·ºC*

Question 19

Calorimetry

Answer 19

Involves the measure of how much heat flows into or out of a substance.

Question 20

Heat = mass · specific heat · change in temperature

Answer 20

Symbolically?

Q = m · C · ∆T

Units?

J = g · J/g·ºC · ºC

Question 21

Combined Gas Law

Answer 21

P₁ V₁ / T1 = P₂ V₂ / T2

Question 22

Ideal Gas Law

Answer 22

P·V = n·R·T

Question 23

1 ATM

Answer 23

760 mmHg

or

760 torr

Question 24

PV = W/M · RT

Answer 24

M = WRT/PT

Question 25

Density

Answer 25

W/V =d = PM/RT

Question 26

q_rxn = q_sol

Question 27

∆H_rxn = q_rxn/mol

Question 28

STP

Answer 28

V = 22.4 L

T = 273 K

P = 1 atm

Question 29

R

Answer 29

R = .0821 L·atm / m·K

Question 30

14.7 psi

Answer 30

1 atm

Question 31

22.4 L

Answer 31

V at STP

Question 32

H_f^o Units

Answer 32

H_f^o = KJ/mol

Question 33

101J

Answer 33

= 1.00L · atm

Question 34

change in Energy = Q + W

Answer 34

W = - P cahnge in V

Question 35

W

Answer 35

= -P · change in Volume