The substance hydrogen has the following properties: normal melting point: 14.0 k normal boiling point: 20.3 k triple point: 7.1×10-2 atm, 13.9 k critical point: 12.8 atm, 33.2 k at temperatures above 33.2 k and pressures above 12.8 atm, h2 is a . h2 does not exist as a liquid at pressures below atm. h2 is a at 4.84 atm and -0.2 k. h2 is a at 1.00 atm and 15.6 k. h2 is a at 7.10×10-2 atm and 34.4 k. which of the following are true?

choose all that apply

the final state of the substance is a gas.

the sample is initially a solid.

the gas initially present will solidify.

the final state of the substance is a solid.

no phase change will occur

supercritical fluid, 0.071, solid, liquid, gas.

The sample is initially a solid.

The final state of the substance is a solid.

No phase change will occur.

Explanation:

Let's refer to the attached phase diagram for H₂ (not to scale).

At temperatures above 33.2 K and pressures above 12.8 atm, H₂ is a supercritical fluid.

H₂ does not exist as a liquid at pressures below 0.071 atm.

H₂ is a solid at 4.84 atm and 0.2 K.

H₂ is a liquid at 1.00 atm and 15.6 K.

H₂ is a gas at 7.10×10-2 atm and 34.4 K.

I think the missing question is this:

A sample of hydrogen is initially at a pressure of 19.1 atm and a temperature of 0.6 K. The pressure on the sample is reduced to 7.10×10⁻² atm at a constant temperature of 0.6 K. Which of the following are true?

Choose all that apply

The final state of the substance is a gas.  NO. At 7.10×10⁻² atm and 0.6 K, hydrogen is a solid.

The sample is initially a solid. YES.

The gas initially present will solidify. NO. Initially, it is solid.

The final state of the substance is a solid.  YES.

No phase change will occur. YES.