Ch5 States of matter

What changes in conditions or molecular properties make it more likely that gases approach ideal behaviour?

• higher pressure

• lower temperature

• more polar molecules

• weaker intermolecular forces

Which pair of substances are both simple molecular?

• C₆₀ and graphene

• C₆₀ and iodine

• graphene and graphite

• graphite and iodine

X, Y and Z are all gases that behave ideally and react according to the equation shown.

X(g) + 2Y(g) → 2Z(g)

When 3.0 mol of X and 3.0 mol of Y are placed inside a container with a volume of 1.0 dm³, they react to form the maximum amount of Z.

The final temperature of the reaction vessel is 120 °C.

What is the final pressure inside the reaction vessel?

• 4.49 × 10⁶ Pa

• 9.80 × 10⁶ Pa

• 1.47 × 10⁷ Pa

• 1.96 × 10⁷ Pa

When an evacuated tube of volume 400 cm³ is filled with gas at 300 K and 101 kPa, the mass of the tube increases by 0.65 g.

Assume the gas behaves as an ideal gas.

What could be the identity of the gas?

• argon

• helium

• krypton

• neon

Flask X contains 5 dm³ of helium at 12 kPa pressure and flask Y contains 10 dm³ of neon at 6 kPa pressure.

If the flasks are connected at constant temperature, what is the final pressure?

• 8 kPa

• 9 kPa

• 10 kPa

• 11 kPa

What is a basic assumption of the kinetic theory, as applied to an ideal gas?

• Collisions between gas molecules are elastic

• Each gas molecule occupies a finite volume.

• Gases consist of particles that experience the force of gravity.

• Gas molecules attract each other with weak intermolecular forces.

Under room conditions, 600 cm³ of a gas, X, has a mass of 0.700 g.

What could X be?

• carbon monoxide

• ethene

• nitrogen

Which statements are correct?

• The hydrogen bonds in ice are more regularly arranged than in water.

• The solidification of water to form ice is exothermic.

• Pure water is less dense than ice.

Which gas is likely to deviate most from ideal gas behaviour?

• HCl

• He

• CH₄

• N₂

• A

• B

• C

• D