CBSE Class XI Chemistry Unit Test (First Term)

1

Express the following in the scientific notation:

a) 0.000456 b) 500.0

(1)

2

Name the experiment which is used to find the charge of an electron & what is the charge of an electron?

(1)

3

What are the drawbacks of Rutherford’s atomic model?

(1)

4

Round up the following up to three significant figures.

a) 46.216 b) 10.4107 c) 0.04597 d) 2808

(2)

5

Calculate the number of atoms in the following;

a) 52 moles of Ar b) 52g of He.

(2)

6

What is the SI unit of mass? How is it defined?

(2)

7

State law of multiple proportion with an example.

(2)

8

The density of 3M solution of NaCl is 1.25g/ml. Calculate molality of the solution.

(2)

9

Define isobars with examples.

(2)

10

Mention the two developments which played a major role in the formulation of Bohr’s model of an atom.

(2)

11

The atomic number and mass number of Calcium are 20 & 40 respectively. Find out the number of electrons, protons and neutrons in a Ca²⁺ ion.

(2)

12

a) How many seconds are there in 3 days?

b) A jug contains 5L of milk. Calculate the volume of milk in m³.

(3)

13

Calculate the concentration of HNO₃ in moles per litre in a sample which has density 1.41g/ mL & the mass percent of nitric acid in it being 69%.

(3)

14

A compound contains 4.07% Hydrogen, 24.27 carbon and 71. 65% chlorine. Its molar mass is 98.96g. What is the empirical formula of the compound?

(3)

15

Write notes on Thomson’s plum pudding model of atom with its important features.

(3)

16

What are the conclusions drawn by Rutherford in his gold foil experiment?

(3)

17

i) Define limiting reagent.

ii) 50.0kg of N₂ (g) and 10.0kg of H₂ (g) are mixed to produce NH₃ (g). Calculate the NH₃(g)

produced. Identify the limiting reagent in this reaction.

(1+4)