Free Printable 9 Kinetic theory of gases STPM

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9 Kinetic theory of gases STPM

Total questions: 20

Worksheet time: 10mins

Name

Class

Date

What is an ideal gas?

I. obey all gas laws at all temperature and pressure

II. real gas near atmospheric pressure and room temperature

III. there is no forces of attraction or repulsion between molecules

I only

II only

I, II

I, II, III

Which graph shows the correct relationship at constant temperature?

$\frac{x}{4}$

$\frac{x}{2}$

What is the approximate number of atoms in a cubic metre of an ideal monatomic gas at a temperature of 27⁰C and a pressure of 1x10⁵Pa.

[Boltzmann constant k = 1.38x10¯²³J K¯¹, R = 8.31 J K¯¹ mol¯¹]

1 x 10²²

6x10²³

2 x 10²⁵

3 x 10²⁶

A sample of carbon-12 has a mass of 3.0 g. Which expression gives the number of atoms in the sample?

(N_A is the symbol for the Avogadro constant.)

0.0030 N_A

0.25 N_A

3 N_A

4 N_A

A surface is bombarded by particles, each of mass m, which have velocity v normal to the surface. On average, n particles strike unit area of the surface each second and rebound elastically.

What is the pressure on the surface?

⅓ nmv²

½ nmv²

nmv

2nmv

Which of the following is not an assumption of kinetic theory of gases?

the total volume of the particles are negligible compare to the volume of container

the number of particles are large

the particles are moving with the same speed

the collisions of particles are elastic

State what is meant by the internal energy of a matter.

it is the sum of kinetic energy of the particles.

it is the sum of potential energy of the particles.

it is the sum of kinetic and potential energy of the particles in random motion.

it is the ratio of kinetic to potential energy of the particles.

A kinetic theory formula relating the pressure p and the volume V of a gas to the root-mean-square speed of its molecules is

p=\frac{1}{3}\ \frac{Nm}{V}<c^2>

In this formula, what does the product Nm represent?

the number of molecules in unit volume of the gas

the total number of molecules in one mole of gas

the total number of molecules present in volume V

the mass of gas present in volume V

10.

The simple kinetic theory of gases may be used to derive the expression relating the pressure p to the density r of a gas. p = $\frac{1}{3}\ \rho<c^2>$

In this expression. what does $<c^2>$ represent?

the average of the squares of the speeds of the gas molecules

the root-mean-square of the gas molecules

the square of the average speed of the gas molecules

the sum of the squares of the speeds of the gas molecules

11.

The density of argon at a pressure of 1.00x10⁵Pa and at a temperature of 300 K is 1.60 kg m¯³. What is the root-mean-square speed of argon molecules at this temperature?

216 m s¯¹

250 m s¯¹

306 m s¯¹

433 m s¯¹

12.

100 ms^-1

300 ms^-1

324 ms^-1

500 ms^-1

13.

14.

In a mixture of two monatomic gases X and Y in thermal equilibrium, the molecules of Y have twice the mass of those of X. The mean translational kinetic energy of the molecules of Y is 6.0x10¯²¹J.

What is the mean translational kinetic energy of the molecules of X?

3.0x10^-21J

4.2x1010^-21J

6.0x10^-21J

8.5x10^-21J

15.

The molecules of an ideal gas at thermodynamic (absolute) temperature T have a root-mean-square speed c_rms.

The gas is heated to temperature 2T.

What is the new root-mean-square speed of the molecules?

$\sqrt{2c_{rms}}$

$\sqrt{2}c_{rms}$

$2c_{rms}$

$4c_{rms}$

16.

The mean kinetic energy of CO₂ gas molecules at temperature T is

$\frac{1}{2}kT$

$\frac{3}{2}kT$

$\frac{5}{2}kT$

3kT

17.

At room temperature, the r.m.s. speeds of oxygen molecules, and carbon dioxide molecules in the air around us are $c_o$ and $c_c$ respectively.
What is the value of the ratio $\frac{c_o}{c_c}$ ?
[Relative atomic mass of oxygen = 16, carbon =12]

0.85

1.17

1.32

1,66

18.

19.

Which statement about the degrees of freedom of a gas molecule at room temperature is correct?

Monatomic gas molecule has two degrees of freedom for rotational motion.

Diatomic gas molecule has three degrees of freedom for translational motion.

Diatomic gas molecule has five degrees of freedom for rotational motion.

Polyatomic gas molecule has two degrees of freedom for rotational motion.

20.

A closed vessel contains 2.5 moles of oxygen gas at temperature of 300 K. The temperature of the gas is then raised to 500 K.

Determine the increase in the internal energy of the gas

4.16x 10³ J

6.24 x 10³ J

1.01 x 10⁴ J

1.25 x 10⁴ J

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9 Kinetic theory of gases STPM

Total questions: 20

Worksheet time: 10mins

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