###### Boyle's law

Select the correct statement of Boyle's law.

For a constant mass of gas at a constant temperature, the pressure exerted by the gas is inversely proportional to the volume it occupies.

###### Charles's law

Select the correct statement of Charles's law.

Select the correct statement.

For a constant mass of gas at a constant pressure, the volume occupied by the gas is proportional to its absolute temperature.

###### Absolute zero

Select the correct definition of absolute zero temperature.

Absolute zero is the temperature at which the pressure of an ideal gas becomes zero. This is 0К on the Kelvin temperature scale, which is equivalent to -273 °C.

###### Absolute temperature

Select the correct definition of absolute temperature.

Absolute temperature is the Kelvin or thermodynamic temperature scale with zero at -273 °C, the temperature at which the pressure of an ideal gas becomes zero.

###### Specific heat capacity

How long will a 1.5 kW kettle take to raise the temperature of 1kg of water from 20° C to 100° C? The specific heat capacity of water is $$4200{J\over kg\times K}$$.

$$\Delta \theta=100-20 = 80K$$

$$\Delta E = c m \Delta T = 4200*1*80=336000J$$

$$\Delta t=E/P=336000/1500=224s$$

###### RMS speed

Find the r.m.s. speed of the five molecules of atmospheric oxygen. Velocities of the molecules are: v1 = 500 m/s, v2 = 496 m/s, v3 = 508 m/s, v4 = 503 m/s, v5 = 499 m/s.

The root-mean-square speed $$c=\sqrt{v^2_1+v^2_2+v^2_3+v^2_4+v^2_5\over 5}\approx501.217m/s$$.

###### RMS speed - 2

What is the root-mean-square speed of a balloon filled with dioxygen at 20° C? The mass of a dioxygen miolecule is $$5.312\times10^{-26} kg$$.

$$T = 20+273 =293K$$

$${m<c^2>\over2}={3\over2}kT$$

Root-mean-square speed is $$\sqrt{<c^2>}=\sqrt{3kT \over m}\approx477.865m/s$$

###### Pressure law

Select the correct definition of pressure law.

Select the correct option.

For a constant mass of gas at a constant volume, the pressure exerted by the gas is proportional to its absolute temperature.

###### Equation of state

Select the correct expression for the equation of state for an ideal gas.

Select the correct option.

The equation of state for an ideal gas is $$pV=nRT$$. It relates the pressure, volume and temperature of an ideal gas. n is the number of moles of the gas; and R is the Universal gas constant. $$R = 8.31{J\over kg\times mol}$$.

###### Ideal gas

Which of the features listed are wrong for an ideal gas?

Select only wrong options.

An ideal gas would have the following properties:
1    The molecules have zero size.
2    The molecules are identical.
3    The molecules collide with each other and the walls of their containers without any loss of energy, collisions take zero time.
4    The molecules exert no forces on each other, except during collisions.
5    There are enough molecules for statistical laws to be applied.