# World of Chemistry

## Educators

Problem 1

How are the three states of matter similar, and how do they differ?

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Problem 2

What is meant by “the pressure of the atmosphere”? What causes this pressure?

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Problem 3

Describe a simple mercury barometer. How is such a barometer used to measure the pressure of the atmosphere?

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Problem 4

Convert the following pressures into atmospheres.
a. 105.2 kPa
b. 75.2 cm Hg
c. 752 mm Hg
d. 767 torr

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Problem 5

Convert the following pressures into units of mm Hg.
a. 0.9975 atm
b. 225,400 Pa
c. 99.7 kPa
d. 1.078 atm

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Problem 6

Convert the following pressures into pascals.
a. 774 torr
b. 0.965 atm
c. 112.5 kPa
d. 801 mm Hg

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Problem 7

For each of the following sets of pressure and volume data, calculate the missing quantity. Assume that the temperature and the amount
of gas remain constant.
a. $V=53.2 \mathrm{mL}$ at 785 $\mathrm{mm} \mathrm{Hg}$ $V=?$ at $700 . \mathrm{mm} \mathrm{Hg}$
b. $V=2.25 \mathrm{L}$ at 1.67 atm $V=2.00 \mathrm{L}$ at $?$ atm
c. $V=5.62 \mathrm{L}$ at 695 $\mathrm{mm} \mathrm{Hg}$ $V=?$ at 1.51 $\mathrm{atm}$

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Problem 8

For each of the following sets of pressure and volume data, calculate the missing quantity. Assume that the temperature and the amount of gas remain the same.
a. $V=291 \mathrm{mL}$ at 1.07 $\mathrm{atm}$ $V=?$ at 2.14 $\mathrm{atm}$
b.$V=1.25 \mathrm{L}$ at 755 $\mathrm{mm} \mathrm{Hg}$ $V=?$ at 3.51 $\mathrm{atm}$
c. $V=2.71 \mathrm{L}$ at 101.4 $\mathrm{kPa}$ $V=3.00 \mathrm{L}$ at? $\mathrm{mm} \mathrm{Hg}$

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Problem 9

If the pressure exerted on the gas in a weather balloon decreases from 1.01 atm to 0.562 atm as it rises, by what factor will the volume of the gas in the balloon increase as it rises?

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Problem 10

What pressure (in atmospheres) is required to compress 1.00 L of gas at 760. mm Hg pressure to a volume of 50.0 mL?

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Problem 11

What is meant by the absolute zero of temperature?

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Problem 12

How can Charles’s law be used to determine absolute zero?

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Problem 13

If a 45.0-mL sample of gas at 26.5 °C is heated to 55.2 °C, what is the new volume of the gas sample (at constant pressure)?

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Problem 14

For each of the following sets of volume and temperature data, calculate the missing quantity. Assume that the pressure and the mass of gas remain constant.
a. $V=25.0 \mathrm{L}$ at $0^{\circ} \mathrm{C} ; V=50.0 \mathrm{L}$ at $?^{\circ} \mathrm{C}$
b. $V=247 \mathrm{mL}$ at $25^{\circ} \mathrm{C}$ $V=255 \mathrm{mL}$ at $?^{\circ} \mathrm{C}$
c. $V=1.00 \mathrm{mL}$ at $2272^{\circ} \mathrm{C} ; V=?$ at $25^{\circ} \mathrm{C}$

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Problem 15

For each of the following sets of volume and temperature data, calculate the missing quantity. Assume that the pressure and the mass of gas remain constant.
a. $V=2.01 \times 10^{2} \mathrm{L}$ at $1150^{\circ} \mathrm{C} ;$ $V=5.00 \mathrm{L}$ at $?^{\circ} \mathrm{C}$
b. $V=44.2 \mathrm{mL}$ at $298 \mathrm{K} ; V=?$ at 0 $\mathrm{K}$
c. $V=44.2 \mathrm{mL}$ at $298 \mathrm{K} ; V=?$ at $0^{\circ} \mathrm{C}$

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Problem 16

If 5.00 L of an ideal gas is cooled from 24 °C to 272 °C, what will the volume of the gas become?

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Problem 17

A sample of neon gas occupies 266 mL at 25.2 °C. At what temperature would the volume of this sample of neon be reduced to half its initial size (at constant pressure)? At what temperature would the volume of this sample of neon be doubled (at constant pressure)?

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Problem 18

The label on an aerosol spray can contains a warning that the can should not be heated to over 130 °F because of the danger of explosion due to the pressure increase as it is heated. Calculate the potential volume of the gas contained in a 500.-mL aerosol can when it is heated from 25 °C to 54 °C (approximately 130 °F), assuming a constant pressure.

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Problem 19

If 0.214 mol of argon gas occupies a volume of 652 mL at a particular temperature and pressure, what volume would 0.375 mol of argon occupy under the same conditions?

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Problem 20

If 46.2 g of oxygen gas occupies a volume of 100. L at a particular temperature and pressure, what volume will 5.00 g of oxygen gas occupy under the same conditions?

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