Question

A sample of methane at a pressure of 1.00 atm and a temperature of 93.1 K is heated at constant pressure to a temperature of 158 K. Which of the following are true? Choose all that apply

a. The liquid initially present will solidify.
b. The final state of the substance is a gas.
c. The sample is initially a solid.
d. The sample is initially a liquid. One or more phase changes will occur.

Answer 1

Answer:

b. The final state of the substance is a gas.

d. The sample is initially a liquid. One or more phase changes will occur.

Explanation:

Methane has the following properties:

• Normal melting point: 90.7 K
• Normal boiling point: 111.65 K

*"Normal" refers to normal pressure (1 atm).

According to this, we can affirm:

• Below 90.7 K, methane is solid.
• Between 90.7 K and 111.65 K, methane is liquid.
• Above 111.65 K, methane is gas.

A sample of methane at a pressure of 1.00 atm and a temperature of 93.1 K is heated at constant pressure to a temperature of 158 K. Which of the following are true? Choose all that apply.

a. The liquid initially present will solidify.  FALSE. The liquid will vaporize.

b. The final state of the substance is a gas.  TRUE.

c. The sample is initially a solid.  FALSE. The sample is initially a liquid.

d. The sample is initially a liquid. One or more phase changes will occur. TRUE.