CIE Chemistry (US-0439): Specimen Questions with Answers 84 - 87 of 240

Question number: 84

MCQ▾

Question

The relative vapour density is calculated with respect to ________.

Choices

Choice (4) Response

a.

Nitrogen

b.

Hydrogen

c.

Carbon

d.

Oxygen

Answer

b.

Explanation

The relative vapour density is calculated with respect to hydrogen.

Question number: 85

MCQ▾

Question

The first chemical basis for classifying acids was given by the scientist named ________.

Choices

Choice (4) Response

a.

Dalton

b.

Lavoisier

c.

None of the above

d.

Question does not provide sufficient data or is vague

Answer

c.

Explanation

The first chemical basis for classifying acids was given by the scientist named Arrhenius. He said that all those substances that give ions as the only positively charged ions in a solution are acids. As ion is unstable, so it combines with water to form ion. So all those substances that give ions as the only positively charged ions in a solution are acids.

Question number: 86

MCQ▾

Question

Conditions necessary during Haber process are ________.

Choices

Choice (4) Response

a.

Presence of molybdenum or iron as a catalyst

b.

High Temperature

c.

All the others

d.

High Pressure

Answer

c.

Explanation

Correct Option is C because haber process cannot be done without Presence of molybdenum or iron as a catalyst, high temperature, high pressure.

Question number: 87

MCQ▾

Question

There are two gas jars, each containing of a gas. Both the jars are maintained at same temperature and pressure. The number of gas molecules in 1st jar is . The number of gas molecules in the jar is ________.

Choices

Choice (4) Response

a.

51530

b.

81860

c.

71750

d.

61640

Answer

b.

Explanation

  • The given problem is related to the number of molecules and volume of the gas at constant temperature and pressure. So Avogadro’s Law is used to calculate the number of molecules present in the other gas jar.

  • Avogadro’s Law states that “equal volumes of all gases under the same conditions of temperature and pressure contain equal number of molecules”.

  • Since both the jars are maintained at same temperature and pressure and they contain the same volume of gases, hence number of molecules in both the jars is equal.

  • Since gas jar has molecules,

  • The number of gas molecules in jar is also .