Chemistry Worksheet Class 11 on Chapter 1 Some Basic Concepts of Chemistry with Answers - Set 4

Chemistry is a branch of science that explores matter and the substances that comprise matter. It also goes over the properties of these substances and the reactions that occur when they combine to form new ones. Chemistry is primarily concerned with interacting with atoms, ions, and molecules to form elements and compounds. These chemical species can interact with one another due to chemical bonds. It’s worth noting that the interactions of matter and energy are also studied in chemistry.

As a fundamental science, chemistry is used in all aspects of a person’s life, from the food consumed to the products used. Chemical science progress has altered the foundation of modern medicine. As a result of ongoing chemistry research, marvel drugs such as penicillin and streptomycin have been developed.

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Chemistry Worksheet Class 11 on Chapter 1 Some Basic Concepts of Chemistry with Answers - Set 4
Chemistry Worksheet Class 11 on Chapter 1 Some Basic Concepts of Chemistry with Answers - Set 4
Chemistry Worksheet Class 11 on Chapter 1 Some Basic Concepts of Chemistry with Answers - Set 4

CBSE Class 11 Chemistry Worksheet Chapter 1 Some Basic Concepts of Chemistry – Set 4

Q1. Calculate the correct number of significant figures: 4.26 – (15.635/5.0)

a.) 1.16

b.) 1.12

c.) 1.2

d.) 1.133

Q2. What amount of dioxygen (in gram) contains 1.8 × 1022 molecules?

a.) 0.960

b.) 96.0

c.) 0.0960

d.) 9.60

Q3. If we consider ⅙ in lace of 1/12 mass of carbon atom is taken to be the relative atomic mass unit, the mass of one mole of a substance will–

a.) Decrease twice

b.) Increase two folds

c.) Remains unchanged

d.) Be a fraction of the molecular mass of the substance

Q4. The molarity of a solution obtained by mixing 800 mL of 0.5 M HCl with 200 mL of 1 M HCl will be ____.

a.) 0.8 M

b.) 0.6 M

c.) 0.4 M

d.) 0.2 M

Q5. The number of molecules present in 1 ml of water is ___.

a.) 1

b.) 1000

c.) 2.69 × 1019

d.) 6.02 × 1020

Q6. Define the atomic mass of an element.

Q7. Classify the following substances into elements, compounds and mixtures:

i.) Milk

ii.) 22-carat gold

iii.) Iodised table salt

iv.) Diamond

v.) Smoke

vi.) Steel

vii.) Brass

viii.) Dry ice

ix.) Mercury

x.) Air

Q8. Perform the following calculations up to a proper number of significant figures:

i.) (1.20 × 10–6) + (6.00 × 10–5)

ii.) (2.164 × 105)½

iii.) (9.13 × 10–2) (7.006 × 10–3)

iv.) 4.00 × 10–2 + 3.26 × 10–3 + 1 × 10–6

Q9. What are some commonly used quantities?

Q10. What do you mean by precision and accuracy?

Q11. A solution is prepared by adding 60 g of methyl alcohol to 120 g of water. Calculate the mole fraction of methanol and water.

Q12. You are given 1L of 0.15 M HCl and 1L of 0.40 M HCl. What is the maximum volume of 0.25 M HCl that you can make from these solutions without adding any water?

Q13. The relative abundance of various isotopes of silicon is as Si (28) = 92.14%, Si (29) = 4.65% and Si (30) = 3.10%. Calculate the average atomic mass of silicon.

Q14. A solution of oxalic acid (COOH)2.2H2O is prepared by dissolving 0.63 g of the acid in 250 mL of the solution. Calculate

i.) Molarity of the solution

ii.) Normality of the solution

Q15. a.) How many moles of nitrogen are needed to produce 8.2 moles of ammonia by reaction with hydrogen?

b.) How many moles of iron can be made from Fe2O3 by using 16 mol of carbon monoxide in the following reaction?

Fe2O3 + 3CO → 2Fe + 3CO2

Q16. Dinitrogen and dihydrogen react with each other to produce ammonia according to the following chemical equation:

N2 + 3H2 → 2NH3

i.) Calculate the mass of ammonia produced if 2.00 × 103 g of dinitrogen reacts with 1.00 × 103 g of dihydrogen.

ii.) Will any of the two reactants remain unreacted?

iii.) If yes, which one and what would be its mass?

Q17.

a.) Calculate the percentage of water of crystallisation in the sample of Mohr salt, FeSO4(NH4)2SO4.6H2O.

b.) Write the empirical formula of the compounds having the molecular formula:

i.) C6H12

ii.) B2H6

iii.) N2O4

iv.) H3PO4

v.) Fe2O3

Q18. State law of definite proportions. How can it be verified experimentally?

Q19.

a.) Calculate the weight of carbon monoxide having the same number of oxygen atoms as present in 88 g of carbon dioxide.

b.) Silver is a very precious metal and is used in jewellery. One-millionth of silver weighs 1.79 × 10–16 g. Calculate the atomic mass of silver.

Q20. A crystalline salt, on being rendered anhydrous, loses 45.6% of its weight. The composition of anhydrous salt is: Al = 10.5%, K = 15.1%, S = 2.8%, and O = 49.6%. Calculate the formula of anhydrous salt and crystalline salt.

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