The atom of the isotope of uranium used to make nuclear bombs (uranium-235) has an atomic number of 92 and a mass number of 235.

1. The number of protons in its nucleus is

(a) 92 (b) 143 (b) 235

2. The number of neutrons in its nucleus is

(a) 92 (b) 143 (b) 235

3. The number of electrons in the atom is

(a) 92 (b) 143 (b) 235

The atomic mass unit u equals 1.67 x 10-27 kg.

This represents

(a) the mass of one atom

(b) the mass of one proton

(c) the mass of one neutron

(d) the mass of one electron

(e) both (b) & (c)

One mole of carbon-12 is defined to have a mass of exactly 12 g.

The atomic mass unit u equals 1.67 x 10-27 kg.

The number of atoms in 1 mole of carbon-12 (or Avogadro's number) is

(a) 0.001 kg/u

(b) 12/u

(c) 0.012 kg/u

(d) not enough information to tell

Which system contains more atoms: 5 mol of helium (A = 4) or 1 mol of neon (A = 20)?

(a) Neon

(b) Helium

(c) They have the same number of atoms

Specific heat capacity of water is 4.19 x 103 J kg-1K-1

The density of water is 1 g/cm3.

1 litre contains 1000 cm3.

A 100-W immersion heater (equal to the power from a 100-W lightbulb) is used to raise the temperature of a 1-litre pot of water to the boiling point, starting from room temperature. About how long would this take, if no heat were lost to the room?

(a) 1 min

(b) 5 min

(c) 20 min

(d) 1 hr

What is the final temperature of the mixture?

(a) T1 - T2 (b) (c)

(d) (e)

T T1 2

2

2

31 2T T

32

1 2T T

T T1 2

3

Equal masses of two miscible liquids are mixed. Liquid #1 starts at temperature T1 and liquid #2 starts at T2. The specific heat capacity of liquid #1 is twice as large as that of liquid #2.

Heat of fusion of water is 3.33 x 105 J kg-1

Heat of vaporization of water is 22.6 x 105 J kg-1

Specific heat capacity of water is 4.19 x 103 J kg-1K-1

Which takes the most heat?

(a) melting 1 kg of ice at 0oC

(b) vaporizing 1 kg of water at 100oC

(c) heating 1 kg of water from the freezing point to the boiling point

(d) All use the same amount of heat

Time

T Solid

A B C D

SolidHeat

Frictionless pistonAThe curve at right represents the temperature of some material, as a function of time, as it is heated with constant power input.

Compared to the heat capacity of the liquid phase, the heat capacity of the gas phase is about

(a) 2 times larger (b) ½ as large (c) roughly equal

2 molesof gas

Two moles of gas at room temperature is contained in the insulated cylinder on the right, closed by a frictionless piston.

1. the pressure of the gas

(a) doubles (b) increases by 4 times

(c) stays the same (d) is reduced by one half

2. the volume of the gas

(a) doubles (b) increases by 4 times

(c) stays the same (d) is reduced by one half

If the temperature of the gas is doubled,

Which of the following curves is that expected for a constant volume of a gas at low pressure, where T is the absolute (or Kelvin) temperature?

T0

P

0 T

P

-273 00

T0

P

0 T0

P

0

a) b)

c) d)