If 150 cc of gas A contains X molecules, how many molecules of gas B will be present in 75 cc of B ? The gases A and B are under the same conditions of temperature and pressure. Name the law on which the problem is based.

According to Avogadro’s law, equal volumes of all gases under similar conditions of temperature and pressure contain an equal number of molecules. So 150 cc of B will also contain X molecules. Hence, the number of molecules present in 75 cc of B will contain X 2 molecules.

Calculate the number of moles in 12 g of oxygen gas. [ O = 16 ]

Molecular mass = 16 × 2 = 32 g 32 g of oxygen gas → 1 mole 1 g of oxygen gas → 1 32 mole Given that 12 g of oxygen gas Number of moles = 12 32 = 0 . 375 mole

E M B I B E

Selina Icse Concise Chemistry For Class 10>Chapter 5 - Mole Concept and Stoichiometry>EXERCISE-5B>Q 20

EASY

10th ICSE

IMPORTANT

Earn 100

What is the mass of $56 {cm}^{3}$ of carbon monoxide at STP? $[C = 12; O = 16]$ .

Important Questions on Mole Concept and Stoichiometry

EASY

10th ICSE

IMPORTANT

Selina Icse Concise Chemistry For Class 10>Chapter 5 - Mole Concept and Stoichiometry>EXERCISE-5B>Q 21

Determine the no. of molecules in a drop of water which weighs

0.09 g .

EASY

10th ICSE

IMPORTANT

Selina Icse Concise Chemistry For Class 10>Chapter 5 - Mole Concept and Stoichiometry>EXERCISE-5B>Q 22

The molecular formula for elemental sulphur is

S_{8}

. In a sample of

5.12 g

of sulphur. How many moles of sulphur are present?

EASY

10th ICSE

IMPORTANT

Selina Icse Concise Chemistry For Class 10>Chapter 5 - Mole Concept and Stoichiometry>EXERCISE-5B>Q 22

The molecular formula for elemental sulphur is

S_{8}

. In a sample of

5.12 g

of sulphur. How many molecules and atoms are present?

MEDIUM

10th ICSE

IMPORTANT

Selina Icse Concise Chemistry For Class 10>Chapter 5 - Mole Concept and Stoichiometry>EXERCISE-5B>Q 23

If phosphorus is considered to contain $P_{4}$ molecules, then calculate the number of moles in $100 g$ of phosphorus.

HARD

10th ICSE

IMPORTANT

Selina Icse Concise Chemistry For Class 10>Chapter 5 - Mole Concept and Stoichiometry>EXERCISE-5B>Q 24

Calculate the gram molecular mass of chlorine if $308 {cm}^{3}$ of it at STP weighs $0.979 g$ .

HARD

10th ICSE

IMPORTANT

Selina Icse Concise Chemistry For Class 10>Chapter 5 - Mole Concept and Stoichiometry>EXERCISE-5B>Q 24

Calculate the volume of

4 g

of

H_{2}

at

4

atmosphere.

MEDIUM

10th ICSE

IMPORTANT

Selina Icse Concise Chemistry For Class 10>Chapter 5 - Mole Concept and Stoichiometry>EXERCISE-5B>Q 24

Calculate the mass of oxygen in $2.2$ litres of ${CO}_{2}$ at STP.

MEDIUM

10th ICSE

IMPORTANT

Selina Icse Concise Chemistry For Class 10>Chapter 5 - Mole Concept and Stoichiometry>EXERCISE-5B>Q 25

A student puts his signature with a graphite pencil. If the mass of carbon in the signature is 10^-12g, calculate the number of carbon atoms in the signature.