Chemistry- vapor pressure

2008-11-02 8:16 pm

1. as the temperature of H2O (l) in a closed system decreases, the vapor pressure of the H2O(l)

a.decreases
b. increases
c. remains the same

2. which sample of water wil have the highest vapor pressure

a. 10 mL at 62 oC
b. 20 mL at 52oC
c. 30 mL at 42 oC
d. 40 mL at 32 oC

3. what is the vapor pressure of a liquid and its normal boiling temperature?

a. 1 atm
b. 2 atm
c. 273 atm
d, 760 atm

4. the vapor pressure of a liquid is 0.92 atm at 60 oC. the normal boiling point of the liquid could be

a. 35 oC
b. 45 oC
c. 55 oC
d. 65 oC

please explain in details how do you get the answers, please!!!

回答 (1)

Uncle Michael

2008-11-03 2:18 am

✔ 最佳答案

1.
The answer is a.

The higher the temperature, the higher is the vapour pressure of a substance.

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2.

The answer is a.

Vapour pressure is affected by temperature only. The higher the temperature, the higher is the vapour pressure of a substance.

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3.
The answer is a.

The question should be:
”What is the vapour pressure of a liquid at its normal boiling temperature?”

A liquid boils when the vapour pressure of the liquid is equal to the atmospheric pressure. The normal atmospheric pressure is 1 atm.

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4.
The answer is d.

A liquid boils when the vapour pressure of the liquid is equal to 1 atm.

At 60oC, the vapour pressure of the liquid is 0.92 atm. The higher the temperature, the higher is the vapour pressure of the liquid. When the vapour pressure reaches 1 atm, the liquid boils. Therefore, a temperature higher than 60oC is expected, and 65oC is the only temperature fulfills the expectation.
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