Basics of Chemistry Worksheet-5

Basics of Chemistry Worksheet-5

1. What is the negatively charged particle that orbits around the nucleus?

(a) electron       (b) proton          (c) neutron        (d) core

2. All atoms have an equal number of _______.

(a) electrons and nucleus            (b) electrons and neutrons

(c) neutrons and protons            (d) electrons and protons

3. Which of the following sentences describes difference between chemical and physical changes?

(a) A chemical change needs energy. A physical change needs heat.

(b) A chemical change is easy. A physical change is hard.

(c) A chemical change is irreversible. A physical change is reversible.

(d) A chemical change is reversible. A physical change is irreversible.

4. Which of the following is not a chemical reaction?

(a) Rusting of an iron rod           (b) Burning fuel in automobile.

(c) Making cheese out of milk   (d) Evaporation of water from a cup.

5. The strength of an acid is called its ____ and the strength of a base is called its _____.

(a) softness, hardness                  (b) sourness, sweetness

(c) acidity, alkalinity                    (d) alkalinity, acidity

6. What is the pH Number of a solution?

(a) It tells if the solution is red or blue.

(b) It tells the temperature of a solution.

(c) It tells how much volume a solution has.

(d) It tells how much acidity or alkalinity a solution has.

7. What is the boiling point of the Compound A?

(a) 60ºC             (b) 120ºC           (c) −20ºC          (d) 100ºC

8. What will be the state of water at 160ºC?

(a) Solid (Ice)                                 (b) Liquid          

(c) Gas (Vapor)                              (d) None of the above

9. Opposite poles of magnets __________ each other.

(a) conduct        (b) repel             (c) attract          (d) insulate

10. When a gas is cooled below its boiling point, it will ___________.

(a) condense     (b) freeze            (c) melt               (d) boil

Answer Key:

(1)–(a); (2)–(d); (3)–(c); (4)–(d); (5)–(c); (6)–(d); (7)–(b); (8)–(c); (9)–(c); (10)–(a)