Chemistry is defined as the study of the composition, structure, and properties of matter, as well as the changes that matter undergoes under various conditions and the laws that govern these changes.
There are several situations in life where chemistry can be useful. Here are some of the most important uses of Chemistry:
- Chemical reactions occur in the food we eat, cosmetics we use, and medicines we take.
- It can assist you in making decisions about a wide range of topics, such as watering plants based on season, determining the proper temperature to bake a cake, selecting the appropriate medicine for acidity, applying a specific SPF sunscreen, and so on.
- It assists you in determining which element your body requires the most. Some people, for example, may require more Vitamin D than others.
- It is also used to improve health, create new elements, supply metals and nuclear energy, manufacture industrial equipment, and is used in wars and construction materials.
Download PDF of Class 11 Chemistry Chapter 1 Some Basic Concepts of Chemistry– Set 2
CBSE Class 11 Chemistry Worksheet Chapter 1 Some Basic Concepts of Chemistry – Set 2
Q1. What is the mass of one atom of C – 12 in grams?
a.) 1.992 × 10–23 g
b.) 1.989 × 10–23 g
c.) 1.892 × 10–23 g
d.) 1.965 × 10–23 g
Q2. Which of the following laws states that the total mass of the reactants is equal to the total mass of the products in a chemical reaction?
a.) Law of multiple proportions
b.) Law of conservation of mass
c.) Avogadro’s law
d.) Law of constant proportions
Q3. The law of multiple proportions was stated by:
a.) Dalton
b.) Proust
c.) Avogadro
d.) None of the above
Q4. The units kg m–1 s–2 are of ___.
a.) Force
b.) Pressure
c.) Acceleration
d.) Velocity
Q5. The empirical formula of glucose is ____.
a.) CH2O
b.) CHO2
c.) C2H2O
d.) CH2O2
Q6. Express the following in the scientific notation:
i.) 0.0048
ii.) 234000
iii.) 8008
iv.) 500.0
v.) 6.0012
Q7. Define Avogadro number and mole. What is their importance?
Q8. In the combustion of methane in the air, what is the limiting reactant and why?
Q9. Is the law of constant composition true for all types of compounds? Explain why or why or why not.
Q10. Sulphuric acid is generally available in the market as an 18.0 M solution. How would you prepare 250 mL of 0.50 M aqueous H2SO4?
Q11. Calculate:
a.) Mass of 1.5 g atoms of calcium
b.) Gram atoms in 12.8 g of oxygen
Q12. The vapour density of a mixture of NO2 and N2O4 is 38.3 at 26.7℃. Calculate the number of moles of NO2 in 100 g of the mixture.
Q13. Balance the following equations by hit and trial method:
a.) KMnO4 + HCl → KCl + MnCl2 + H2O + Cl2
b.) Mg3N2 + H2O → Mg(OH)2 + NH3
c.) Al4C3 + H2O → Al(OH)3 + CH4
d.) FeS2 + O2 → Fe2O3 + SO2
e.) K2Cr2O7 +H2SO4 → K2SO4 + Cr2(SO4)3 + H2O + O2
Q14. Lithium oxide removes water from the air according to the reaction:
Li2O (s) + H2O (g) → 2LiOH (s)
If 72 kg of water is to be removed and 35 kg of Li2O is available,
i.) Which reactant is limiting?
ii.) How many kg of excess reactant is left?
Q15. A compound (molecular mass = 246) has the following data:
| Element | % Composition | Relative No. of Atoms |
|---|---|---|
| A | 9.76 | 0.406 |
| B | 13.01 | 0.406 |
| C | 26.01 | 1.625 |
| D | 51.22 | 2.846 |
From the data, find out
i.) Atomic masses of the elements A, B, C and D
ii.) Simple ratio
iii.) Molecular formula of the compound
Q16. What is the modern atomic theory?
Q17. Phosphorus and chlorine form two compounds. The first compound contains 22.54% by mass of phosphorus and 77.46% by mass of chlorine. In the second compound, the percentage is 14.88 for phosphorus and 85.12 for chlorine. Show that these data are consistent with the law of multiple proportions.
Q18. Calculate the following:
i.) The number of molecules present in 2.24 dm3 of carbon dioxide at N.T.P.
ii.) Mass of an atom of oxygen
iii.) The number of oxygen atoms in 2 mol of ozone.
iv.) The volume occupied by 4.4 g of SO2 at N.T.P.
Q19. A 2.0 g of a sample containing Na2CO and NaHCO3 loses 0.248 g when heated to 300℃, the temperature at which NaHCO3 decomposes to Na2CO3, CO2 and water. What is the percentage of Na2CO3 in the mixture?
Q20. A welding fuel gas contains carbon and hydrogen only. Burning a small sample of it in oxygen gives 3.38 g of carbon dioxide, 0.690 g of water and no other products. A volume of 10.0 L of this gas is found to weigh 11.6 g. Calculate the following:
i.) Empirical formula
ii.) Molar mass of the gas
iii.) Molecular formula
Download PDF to access answers of the Chemistry Worksheet for Class 11 Chemistry Chapter 1 Some Basic Concepts of Chemistry Set – 2
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Read Also:
- Class 11 Chemistry Chapter 1 Some Basic Concepts of Chemistry MCQs
- Important Questions for Class 11 Chemistry Chapter 1 Some Basic Concepts of Chemistry
- Chemistry Concept Questions and Answers
- CBSE Class 11 Chemistry Practical
- Significant Figures Chemistry
- Laws of Chemical Combination for Elements and Compounds
- Mole Concept
- Empirical Formula & Molecular Formula
