Chemistry Worksheet Class 11 on Chapter 1 Some Basic Concepts of Chemistry with Answers - Set 3

Chemistry is a branch of science that studies matter and the substances that makeup matter. It also discusses the properties of these substances as well as the reactions that occur when they combine to form new substances. Chemistry is primarily concerned with atoms, ions, and molecules, which combine to form elements and compounds. Chemical bonds allow these chemical species to interact with one another. It is worth noting that the interactions of matter and energy are also investigated in the field of chemistry.

Chemistry is the study of the properties, compositions, and structures of elements and compounds, as well as how they can change and the energy that is released or absorbed during such changes.

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Chemistry Worksheet Class 11 on Chapter 1 Some Basic Concepts of Chemistry with Answers - Set 3
Chemistry Worksheet Class 11 on Chapter 1 Some Basic Concepts of Chemistry with Answers - Set 3
Chemistry Worksheet Class 11 on Chapter 1 Some Basic Concepts of Chemistry with Answers - Set 3

CBSE Class 11 Chemistry Worksheet Chapter 1 Some Basic Concepts of Chemistry – Set 3

Q1. In a hydrocarbon, the mass ratio of hydrogen and carbon is 1:3; the empirical formula of hydrocarbon is ____.

a.) CH4

b.) CH2

c.) C2H

d.) CH3

Q2. 80g of oxygen contains as many atoms as in ____.

a.) 10 g of hydrogen

b.) 5 g of hydrogen

c.) 8 g of hydrogen

d.) 1 g of hydrogen

Q3. A mixture of gases contains H2 and O2 gases in the ratio 1:4. What is the molar ratio of the two gases in the mixture?

a.) 16:1

b.) 2:1

c.) 1:4

d.) 4:1

Q4. Which of the following concentration terms is/are independent of temperature?

a.) Molality

b.) Mole fraction

c.) Molarity

d.) Normality

Q5. Which of the following contains the highest number of atoms?

a.) 1.0 g of water

b.) 1.0 g of silver

c.) 1.0 g of nitrogen

d.) 1.0 g of propane

Q6. What physical quantities are represented by the following units, and what are their common names?

i.) kg m2 s–2

ii.) kg m s–2

iii.) dm2

Q7. What do you understand by the following terms?

i.) Empirical formula

ii.) Molecular formula

Q8. State the law of multiple proportions.

Q9. Define elements, compounds and mixtures.

Q10. Express the following up to three significant places:

a.) the height of a man, 5 feet 9 inches in centimetres (1 inch = 2.54 cm)

b.) one-millionth of one

c.) four thousand

d.) decimal equivalent of ⅔

Q11. a.) Balance the following equations:

i.) 4H3PO3 → 3H3PO4 + PH3

ii.) Ca + 2H2O → Ca(OH)2 + H2

iii.) Fe2(SO4)3 + 3NH3 + 3H2O → 2Fe(OH)3+ 3(NH4)2SO4

b.) Write the empirical formulae of the compounds having the following molecular formulae:

i.) C6H6

ii.) H2O2

iii.) Na2CO3

Q12. Two oxides of metal contain 27.6% and 30% of oxygen, respectively. If the formula of the first compound is M3O4, find the formula of the second compound.

Q13. Calculate the difference in the number of carbon atoms in 1.0 g of C –14 isotope and 1.0 g of C – 12 isotope.

Q14. Calculate the percentage yield of the reaction if 64 g NaBH4 reacts with iodine to produce 15.0 g of BI3.

Q15. Calculate the number of atoms of each type in 5.3 g of Na2CO3.

Q16. 3.0 g of H2 reacts with 29.0 g of O2 to yield H2O.

i.) Which is the limiting reactant?

ii.) Calculate the amount of H2O that can be formed,

iii.) Calculate the amount of one of the reactants which remains unreacted.

Q17. Commercially available sulphuric acid contains 93% acid by mass and has a density of 1.84 g mL–1.

Calculate-

i.) Molarity of the solution

ii.) The volume of concentrated acid required to prepare 2.5 L of 0.50 M H2SO4.

Q18. A solid mixture (5.0 g) consisting of lead nitrate and sodium nitrate is heated below 600℃ until the weight of the residue is constant. If the loss in weight is 28%, calculate the amount of lead nitrate and sodium nitrate in the mixture.

Q19. Calculate the empirical formula and molecular formula of the compound having the following percentage composition:

Na = 36.5%, H = 0.8%, P = 24.6%, O = 38.1%

The molecular mass of the compound is 126 amu. Also, name the compound.

Q20. 2.5g of an impure sample of sodium bicarbonate, when heated strongly, gave 300 ml of carbon dioxide measured at 27℃ and 760 mm pressure. Calculate the percentage purity of the sample.

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