At a constant pressure, the volume of a gas doubles when the temperature in kelvins doubles. This is a statement of which gas law? Boyle’s law
Charles’s law
Gay-Lussac’s law
combined gas law

Boyle’s law and,Charles’s law

Explanation:

For a fixed mass of gas at constant pressure, the volume is directly proportional to the kelvin temperature. That means, for example, that if you double the kelvin temperature from, say to 300 K to 600 K, at constant pressure, the volume of a fixed mass of the gas will double as well.

can be answered using momentum.

momentum = p

p1= mass1 * velocity1

p1 = p2

therefore

p1 = 6kg * 4m/s

p1 = 24kgm/s

p2=m2 * v2

24 kgm/s = 7kg * v2

v2 = 24 kgm/s / 7kg

v2= 3.42 m/s

d) physical means can be used to separate the components of air.