Lakhmir Singh solutions for Chemistry [English] Class 10 ICSE chapter 5 - Mole Concept and Stoichiometry [null edition]

State whether the following statement is True or False.

A mole is a collection of elementary particles.

State whether the following statement is True or False.

The simplest ratio of volumes of nitrogen, hydrogen and ammonia in the formation of ammonia is 1 : 3 : 1.

State whether the following statement is True or False.

Avogadro's number is denoted by N_A.

According to ______ law, equal volumes of all gases under the same conditions of temperature and pressure contain the same number of molecules.

______ is the smallest particle of an element that can take part in a chemical reaction.

Atomicity of sulphur is ______.

Which of the following is a tetratomic molecule?

The simple ratio of volumes in which hydrogen and chlorine molecules combine to give HCl is ______.

State Gay-Lussac’s law of combining volumes.

State the distinction made by Avogadro between atoms and molecules.

Define limiting reagent. Give a suitable example.

What volume of ammonia is required to produce 130 cm³ of steam?

\[\ce{4NH3 + 5O2 -> 4NO + 6H2O}\]

A sample of ammonium nitrate upon heating yields 7.58 dm³ of steam.

\[\ce{NH4NO3 -> N2O + 2H2O}\]

What volume of N₂O is released?

State whether the following statement is True or False.

Atomic mass unit, 1 u equals to one-twelfth the mass of a carbon-12 atom.

State whether the following statement is True or False.

1 mole of sulphur (S₈) contains 8 × 6.022 × 10²³ atoms.

State whether the following statement is True or False.

The vapour density of a gas or vapour is twice its relative molecular mass.

Gram molecular mass of any gas occupies ______ dm³ of volume at S.T.Р.

Weight of 6.022 × 10²³ molecules of a gas is equal to its gram ______ mass.

Gram molecular mass of water is ______ g.

1 L of any gas would weigh how many times its vapour density.

How many grams of ammonia is present in its 0.2 mole?

Number of molecules in 0.49 g of H₂SO₄ is ______ × 10²¹.

What do you mean by Atomic mass?

What do you understand by the term mole.

Define the term:

Vapour density

Calculate the mass of one atom of nitrogen and one molecule of nitrogen (atomic mass of nitrogen = 14 u).

Calculate the mass of 15.055 × 10²² molecules of carbon dioxide.

What will be the atomicity of nitrogen if 14 g of nitrogen occupies 11.2 L at S.T.P.?

What will be the volume (in cm³) occupied by 0.8 g of Cl₂ at S.T.P.?

What volume will 26.4 g of a gas will occupy at S.T.P. if its vapour density is 22?

State whether the following statement is True or False.

The empirical formula of hydrogen peroxide is OН.

State whether the following statement is True or False.

The empirical formula and molecular formula of a compound may be the same.

State whether the following statement is True or False.

Benzene has the same empirical and molecular formula.

The percentage composition of an element in a compound is its mass in ______ g of the compound.

The percentage of water of crystallisation in hydrous copper sulphate is ______.

The empirical formula of acetic acid is ______.

Empirical formula of a compound whose empirical formula weight is 83.

The first step in finding the empirical formula is to divide the given percentage composition of the elements by ______.

Which of the following information is not given by a balanced chemical equation?

Define percentage composition with an example.

Differentiate between molecular formula mass and empirical formula mass.

An organic compound contains 4.09% hydrogen and 71.19% of chlorine and the rest carbon. If its molecular mass is 148.5 g, find its empirical formula and chemical formula.

What volume of CO₂ under S.T.P. conditions will be obtained by burning 1 kg of carbon in an excess of oxygen?

True or False.

An atom is the smallest particle of an element or a compound that can exist independently.

True or False.

One mole of any gaseous substance will occupy 11.2 dm³ of volume at S.T.P.

True or False.

Number of molecules of oxygen in one mole of SO₂ is 2 × 6.022 × 10²³.

True or False.

Gram molecular mass of NaNO₃ is 85 g.

True or False.

14 g of carbon contains 6.022 × 10²³ atoms of carbon.

According to ______ law, when gases react, they do so in volumes which bear a simple ratio to one another and to the volume of the gaseous product, provided that all the volumes are measured at the same temperature and pressure.

Krypton is a ______ atomic molecule.

The atomicity of ozone is ______.

22.4 L of a gas at S.T.P. contains ______ molecules of the gas.

A gas has its vapour density d. d g of the gas will occupy ______ L of volume at S.T.P.

The value of pressure at S.T.P.:

Gay-Lussac's law is applicable to ______.

What mass of N₂ will be required to produce 34.0 g of NH₃ by the reaction, \[\ce{N2 + 3H2 -> 2NH3}\]?

Which gas sample will have the least number of molecules at S.T.Р.?

How many molecules are there in 8 g of oxygen (O₂)?

1 g of hydrogen contains how many atoms of hydrogen?

Match the following columns and choose the suitable option.

What do you mean by stoichiometry?

State:

Avogadro’s law

How is a mole related to the molecular mass?

Give an example where two compounds have same molecular as well as empirical formula mass.

Give the relation between molecular formula and empirical formula.

Define atomicity of a gas.

Differentiate between gram atomic mass and gram molecular mass.

Derive the relationship between Relative molecular mass and Vapour density.

How can the atomicity of a compound be determined with the help of Avogadro’s law?

Show that the gram molecular mass of any gas occupies 22.4 L of volume at S.T.P.

Discuss at least three applications of Avogadro’s law.

What qualitative information can be obtained from a chemical reaction?

Calculate the volume of oxygen required to burn completely a mixture of 18.2 cm³ of ethylene and 9.4 cm³ of hydrogen to carbon dioxide.

\[\ce{C2H4 + 3O2 -> 2CO2 + 2H2O}\]

\[\ce{2H2 + O2 -> 2H2O}\]

100 mL of a gaseous mixture contains 38% of CH₄, 35% of H₂ and 12% of C₂H₄ and 15% of СО. This mixture was mixed with 200 mL of oxygen and was exploded. Calculate the volume and the composition of the resulting mixture when cooled to room temperature and pressure.

Calculate the molecular mass of the following compound:

Sugar (C₁₂H₂₂O₁₁)

Calculate the molecular mass of ethanoic acid, CH₃COOH.

(Atomic masses: C = 12 u; H = 1 u; O = 16 u)

Calculate the molecular mass of the following compound:

Urea (NH₂CONH₂)

Calculate the molecular mass of the following:

CuSO₄·5H₂O

Given atomic masses of Cu = 63·5, H = 1, O = 16, C = 12, N = 14, Mg = 24, S = 32

Calculate the molecular mass of the following:

Na₂SO₄.10H₂O

Given atomic masses of Na = 23, H = 1, O = 16, C = 12, N = 14, Mg = 24, S = 32

What is the mass percent composition of carbon in Na₂CO₃.

The concentration of an aqueous solution of sugar is 5% by mass. Calculate the amount of sugar present in 554 g of the aqueous solution.

125 cm³ of ethane is burnt in just sufficient air (containing 20% oxygen by volume). Find the total volume of the mixture at constant temperature and pressure.

\[\ce{C2H6 + 7O2 -> 4CO2 + 6H2O}\]

A sample of hard water contains 32 g of calcium carbonate in it. Calculate the number of calcium and carbonate ions present in the sample.

Calculate the gram molecular mass of oxygen if 385 cm³ of volume is occupied by 0.55 g of oxygen at S.T.P.

Calculate the mass of nitrogen in 2240 cm³ of nitrogen dioxide at S.T.P.

What volume of nitrogen (N₂) and oxygen (O₂) measured at S.T.P. will be required to prepare 4.6 g of nitrogen dioxide?

What mass of CO₂ would occupy a volume of 38 L at 27°C and 600 mm Hg pressure?

A high-pressure tank stores 70 g of hydrogen gas. Under similar conditions of temperature and pressure, the same tank stores 350 g of a gas A and 560 g of a gas B. Find the relative molecular masses of the gas.

A gas X has a density of 3 g/L at 27°C and 1520 mm Hg pressure. Calculate its gram molecular mass.

A compound with empirical formula AB has its vapour density 2 times its empirical formula weight. Determine its molecular formula.

If 33.1 g of lead nitrate is heated, calculate the mass of lead oxide and the volume of nitrogen and oxygen obtained at S.T.P.

12.5 g of zinc carbonate sample on heating decomposes to give carbon dioxide and 6.0 g of zinc oxide. Calculate the percentage purity in the zinc carbonate sample. (Given atomic mass of Zn = 65 g)

Determine the empirical formula of a compound containing 47.9‰ K, 5.5‰ beryllium and 46.6‰ fluorine by mass.

Given that the relative molecular mass of copper oxide is 80, what volume of ammonia (measured at STP) is required to completely reduce 120g of copper oxide? The equation for the reaction is:

\[\ce{3CuO + 2NH3 → 3Cu + 3H2O + N2}\]

A compound X consists of 4.8% carbon and 95.2% bromine by mass. Determine the empirical formula of this compound working correctly to one decimal place (C = 12; Br = 80).

A compound X consists of 4.8% carbon and 95.2% bromine by mass. If the vapour density of the compound is 252, what is the molecular formula of the compound?

1. A compound has the following percentage composition by mass: carbon 14.4%, hydrogen 1.2% and chlorine 84.5%. Determine the empirical formula of this compound. Work correctly to 1 decimal place. (H = 1; C = 12; Cl = 35.5)
2. The relative molecular mass of this compound is 168, so what is its molecular formula?
3. By what type of reaction could this compound be obtained from ethyne?

An organic compound with vapour density = 94 contains C = 12.67%, H = 2.13% and Br = 85.11%. Find the molecule formula.

[Atomic mass: C = 12, H = 1, Br = 80]

A gaseous hydrocarbon contains 82.76% of carbon. Given that its vapor density is 29, find its molecular formula. [C = 12, H = 11]

1. The percentage composition of a gas is:
   Nitrogen 82.35%, Hydrogen 17.64%.
2. Find the empirical formula of the gas. [N = 14, H = 1]

 Find the empirical formula and the molecular formula of an organic compound from the data given below : 
C = 75.92%, H = 6.32% and N = 17.76%
The vapour density of the compound is 39.5.
[C = 12, H = 1, N = 14]