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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

User Tex
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2 Answers

6 votes

Answer:

The sample is initially a gas

The starting temperature is above the boiling point and the pressure is standard @ 1 atm.

The final state of the substance will be a liquid.

Since the pressure has been kept a 1 atm and the temperature is above the melting point but below the boiling point.

Step-by-step explanation:

User MuraliGanesan
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5.3k points
2 votes

Answer:

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.

Step-by-step 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.

The substance hydrogen has the following properties: normal melting point: 14.0 K-example-1
User Misterhex
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