Some basic concepts of chemistry MCQ

Multiple Choice Questions

Question 1
Which of the following terms are unitless?
(a) Molality
(b) Molarity
(c) Mole fraction
(d) Mass percent

Question 2
16 g of oxygen has same number of molecules as in
(a) 16 g of CO
(b) 28 g of $N_2$
(c) 14 g of $N_2$
(d) 1.0 g of $H_2$

Question 3
Number of significant Figures in the numer 1.065
(a) 3
(b) 4
(c) 2
(d) 1

Question 4
How many moles of atom are contained in 32.7 g of Zn
(a) .200
(b) .500
(c) 1.50
(d) .0118

Question 5
What will be the molality of the solution containing 18.25 g of HCl gas in 500 g of water?
(a) 0.1 m
(b) 1 M
(c) 0.5 m
(d) 1 m

Question 6
Calculate the number of Moles of $Cu(C_2H_3O_2)_2$ present in 200 g
(a) 1.1 mol
(b) 1 mol
(c) .9 mol
(d) 1.2 mol

Question 7
The percentage of Carbon is $Ca(HCO_3)_2$ is
(a) 15%
(b) 1.8%
(c) 14.8%
(d) 15.2%

Question 8
Which of the following statements about a compound is incorrect?
(a) A molecule of a compound has atoms of different elements.
(b) A compound cannot be separated into its constituent elements by physical methods of separation.
(c) A compound retains the physical properties of its constituent elements.
(d) The ratio of atoms of different elements in a compound is fixed

Question 9
Calculate the standard molar volume of oxygen gas. The density of $O_2$ gas at NTP is 1.429g/L.
(a) 22.39litres
(b) 21.2 Litres
(c) 24 Litres
(d) None of the above

Question 10
Calculate the number of oxygen atoms in 50 g of CaCO_3.
(a) $6.033 \times 10^{23}$ atoms
(b) $9.033 \times 10^{23}$ atoms
(c) $8.033 \times 10^{23}$ atoms
(d) $3.033 \times 10^{23}$ atoms

Question 11
What will be the molarity of a solution, which contains 5.85 g of NaCl(s) per 500 mL?
(a) 4 mol/L
(b) 20 mol/L
(c) 0.2 mol/L
(d) 2 mol/L

Question 12
the mass of $2.044 \times 10^{23}$ carbon atoms.
(a) 12 g
(b) 36 g
(c) 24 g
(d) 48 g

Question 13
How many gram of solute is required to prepare 1.0 L of 1 M CaCl2.6H2O?
(a) 200 g
(b) 216 g
(c) 219 g
(d) None of the above

Question 14
Which of the following reactions is not correct according to the law of conservation of mass.
(a) $2Mg(s) + O_2(g) \rightarrow 2MgO(s)$
(b) $C_3H_8(g) + O_2(g) \rightarrow CO_2(g) + H_2O(g)$
(c) $P_4(s) + 5O_2(g) \rightarrow P_4O_{10}(s)$
(d) $CH_4(g) + 2O_2(g) \rightarrow CO_2(g) + 2H_2O (g)$

Question 15
How many mL of water must be added to 200 mL of .65 M HCL to dilute the solution to .20 M
(a) 450 mL
(b) 400 mL
(c) 350 mL
(d) 500 mL

Question 16
The number of Gram molecules of oxygen in $6.02 \times 10^24$ CO molecules is
(a) 10 gm-molecules
(b) 5 gm-molecules
(c) 1 gm -molecules
(d) .5 gm-molecules

Question 17
Which of the following has the largest number of atoms
(a)0.5 g-atoms of Cu
(b)0.635 g Cu
(c) 0.25moles of Cu atoms
(d)1g of Cu

Question 18
A measured temperature on Fahrenheit scale is 200 °F. What will this reading be on Celsius scale?
(a) 40 °C
(b) 94 °C
(c) 93.3 °C
(d) 30 °C

Question 19
1 Mole of $CH_4$ contains
(a) $6.02 \times 10^{23}$ atoms of H
(b) 4 gm-atoms of hydrogen
(c) $1.81 \times 10^{23}$ molecules of $CH_4$
(d) 3g of Carbon

Question 20
Which of the following pairs have the same number of atoms?
(a) 16 g of $O_2$(g) and 4 g of $H_2$(g)
(b) 16 g of $O_2$ and 44 g of $CO_2$
(c) 28 g of $N_2$ and 32 g of $O_2$
(d) 12 g of C(s) and 23 g of Na(s)


1. (c) and (d)
2. (c) and (d)
3. (b)
4. (b)
5. (d)
6. (a)
7. (c)
8. (c)
9. (a)
10. (b)
11. (c)
12. (c)
13. (c)
14. (b)
15. (a)
16. (b)
17. (a)
18. (c)
19. (b)
20. (c), (d)

Also Read

Latest Updates
Synthetic Fibres and Plastics Class 8 Practice questions

Class 8 science chapter 5 extra questions and Answers

Mass Calculator

3 Fraction calculator

Garbage in Garbage out Extra Questions7