Chemistry - 9 Chapter - 2Chemical combination and Chemical EquationsTest - 15

Chemistry - 9 Chapter - 2
Chemical combination and Chemical Equations
Test - 15

1. law of multiple proportions proves atoms do not break during a chemical change.

a) True
b) False

2. A chemical equation must obey the law of multiple proportions.

a) False
b) True

3. A complete and balanced equation tells us the Atomic Mass ratio between the reactants and products.

a) False
b) True

4. In addition reaction two different compounds or elements react to give more than one compound.

a) False
b) True

5. Due to isotopes one atom may have different atomic numbers?

a) False
b) True

6. Which forms of energies are produced when the natural gas burned?

a) Sound and light.
b) Fire and light.
c) Heat and light.
d) Heat and lfire.

7. What is the scale to measure the atomic masses of elements?

a) The unit mass is 1/12 of the mass of C-12.
b) The unit mass is 1/12 of the mass of C-2.
c) The unit mass is 1/10 of the mass of C-12.
d) The unit mass is 1/12 of the mass of H

8. Find out molecular mass of H2 O?

a) 1x2 + 1x16= 18 mg
b) 1x1 + 1x16= 17 g
c) 1x2 + 1x16= 18 a.m.u.
d) 1x2 + 1x16= 18 g

9. Find out formula mass of NaCl?

a) Formula mass of NaCl = 23 + 35.5 = 48.5 g
b) Formula mass of NaCl = 23 + 35.5 = 58.5 g
c) Formula mass of NaCl = 23 + 35.5 = 58.5 a.m.u.
d) Formula mass of NaCl = 23 + 35.5 = 58.5 mg

10. 1 mole of CO₂ molecules = 6.02 x 10²³ molecules= ?

a) 44g
b) 46g
c) 42g
d) 48g

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