Gases

Question 1

State methods of displacing hydrogen:

Answer 1

• Electrolysis of water, process of passsing an electric current through water to cause it to decompose
• Displace it from water molecule using a metal, must be higher in activity than hydrogen
• Decomposing natrual gas with heat (such has methane)

Question 2

List the activity series of metals:

Answer 2

Potassium (In cold water)

Calcium (In cold water)

Sodium (In cold water)

Magnesium (In hot water)

Aluminum (In dilute acids)

Zinc (In dilute acids)

Iron (In dilute acids)

Tin (In dilute acids)

Hydrogen

Copper (Not active enough)

Mercury (Not active enough)

Silver (Not active enough)

Gold (Not active enough)

Very Active metal + Water= Hydrogen + Metal hydroxide

Active metal + Dilute acid= Hydrogen + Salt of the acid

Question 3

State the three basic assumptions to the Kinetic-Molecular Theory:

Answer 3

1. Matter in all its forms (solid, liquid, and gas) is composed of extremely small particles. The space occupied by the gas particles themselves is ignored in comparison with the volume of the space in which they are contained.
2. The particles of matter are in constant motion. In solids, this motion is restricted to a small space. In liquids, the particles have a more random pattern but still are restricted to a kind of rolloing over one another. In a gas, the particles are in continuous, random, straight-line motion.
3. When these particles collide with each other or with the walls of the container, there is no loss of energy.

Question 4

State Graham’s Law of Effusion:

Answer 4

The rate of effusion of a gas is inversely proportional to the square root of its molecular mass.

Formula:

Rate A/ Rate B= √Molecular mass of B/ √Molecular mass of A

Question 5

State Charles’s Law

Answer 5

If the pressure remains constant, the volume of a gas varies directly as the absolute temperature.

Formula:

V₁/T₁= V_2/T₂

Question 6

State Boyle’s Law:

Answer 6

If the temperature remains constant, the volume of a gas varies inversely as the pressure changes

Formula:

P₁V₁= P₂V₂

Question 7

State the Combined Gas Law:

Answer 7

Combination of Charles’s Law and Boyle’s Law.

Formula: P₁V₁/ T₁= P₂V₂/ T₂

Question 8

State Gay-Lussac’s Law:

Answer 8

At constant volume, the pressure of a given mass of gas varies directly with the absolute temperature

Formula:

P₁/T₁=P₂T₂

Question 9

State Dalton’s Law of Partial Pressures:

Answer 9

When a gas is made up of a mixture of different gases, the total pressure of the mixture is equal to the sum of the partial pressure of the components.

Formula:

P_total= P_{gas 1} + P_{gas 2} + P_{gas 3} + …

Question 10

State the Ideal Gas Law:

Answer 10

Law derived from the Kinetic-Molecular theory relating pressure, volume, temperature, and number of moles.

Formula:

PV=nRT

P=Pressure

V=Volume

n=Number of moles

R=Ideal Gas Constant

T=Temperature