01 Chemical Arithmetic Quiz - Chemistry Quiz #mcq.cetjob - Multiple choice questions and Objectives
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01 Chemical Arithmetic Quiz - Chemistry Quiz 

Chemical Arithmetic

In this Chemistry quiz section, we are going to share Chemistry study materials as well as some most important multiple choice quiz from the following section i.e. Significant figures, Units for measurement, Matter, and Separation of mixture; Atomic, Molecular and Equivalent masses; The mole concept; Percentage composition & Molecular formula;  Chemical stoichiometry and Critical Thinking Questions.

Chemistry is basically an experimental science. In it we study physical and chemical properties of the substance and measure it up to possibility. The results of measurement can we reported in two steps,
(a) Arithmetic number, (b) Unit of measurement.
Every experimental measurement varies slightly from one another and involves some error or uncertainty depending upon the skill of the person making the measurements and measuring instrument. The closeness of the set of values obtained from identical measurement called precision and a related term refers to the closeness of a single measurement to its true value called accuracy.

Laws of chemical combination
Various chemical reactions take place according to certain laws, known as the Laws of chemical combination.
(1) Law of conservation of mass: It was proposed by Lavoisier and verified by Landolt. According to this law, Matter is neither created nor destroyed in the course of chemical reaction though it may change from one form to another.  The total mass of materials after a chemical reaction is the same as the total mass before the reaction.
(2) Law of constant or definite proportion: It was proposed by Proust. According to this law, A pure chemical compound always contains the same elements combined together in the fixed ratio of their weights whatever its methods of preparation may be.
(3) Law of multiple proportions: It was proposed by Dalton and verified by Berzelius. According to this law, When two elements A and B combine to form more than one chemical compound then different weights of A, which combine with a fixed weight of B, are in the proportion of simple whole numbers.
(4) Law of equivalent proportion or law of reciprocal proportion: It was proposed by Ritcher. According to this law, The weights of the two or more elements which separately react with same weight of a third element are also the weights of these elements which react with each other or in simple multiple of them.
(5) Gay-Lussac’s law : It was proposed by Gay–Lussac and is applicable only for gases. According to this law, When gases combine, they do so in volumes, which bear a simple ratio to each other and also to the product formed provided all gases are measured under similar conditions. Gay-Lussac’s law was based on experimental observation.

1. Given the numbers : 161cm, 0.161cm, 0.0161 cm. The number of significant figures for the three numbers are
(a) 3, 4 and 5 respectively
(b) 3, 3 and 3 respectively
(c) 3, 3 and 4 respectively
(d) 3, 4 and 4 respectively
Sol:   B
2. Significant figures in 0.00051 are
(a) 5 (b) 3
(c) 2 (d) 4
Sol:   C
3. Difference in density is the basis of
(a) Ultrafiltration
(b) Molecular sieving
(c) Gravity Separation
(d) Molecular attraction
Sol:   C

4. Which of the following elements of matter would best convey that there is life on earth
(a) Oxygen (b) Hydrogen
(c) Carbon (d) Iron
Sol:   C
5. Which of the following contains only one element
(a) Marble (b) Diamond
(c) Glass (d) Sand
Sol:   A
6. The percentage of copper and oxygen in samples of CuO obtained by different methods were found to be the same. This illustrates the law of
(a) Constant proportions
(b) Conservation of mass
(c) Multiple proportions
(d) Reciprocal proportions
Sol:   A

7. Two samples of lead oxide were separately reduced to metallic lead by heating in a current of hydrogen. The weight of lead from one oxide was half the weight of lead obtained from the other oxide. The data illustrates
(a) Law of reciprocal proportions
(b) Law of constant proportions
(c) Law of multiple proportions
(d) Law of equivalent proportions
Sol:   C

8. The chemical equation is balanced according to the law of
(a) Multiple proportion
(b) Reciprocal proportion
(c) Conservation of mass
(d) Definite proportions 
Sol:  C

9. Avogadro number is
(a) Number of atoms in one gram of the element
(b) Number of millilitres which one mole of a gaseous substances occupies at NTP
(c) Number of molecules present in one gram molecular mass of a substance
(d) All  of these
Sol:   C

10. Different proportions of oxygen in the various oxides of nitrogen prove the
(a) Equivalent proportion
(b) Multiple proportion
(c) Constant proportion
(d) Conservation of matter
Sol:   B

11. The law of multiple proportions is illustrated by the two compounds
(a) Sodium chloride and sodium bromide
(b) Ordinary water and heavy water
(c) Caustic soda and caustic potash
(d) Sulphur dioxide and sulphur trioxide
Sol:  A
12. For preparing 0.1 N solution of a compound from its impure sample of which the percentage purity is known, the weight of the substance required will be
(a) More than the theoretical weight
(b) Less than the theoretical weight
(c) Same as the theoretical weight
(d) None of these
13. When potassium permanganate is titrated against ferrous ammonium sulphate, the equivalent weight of potassium permanganate is
(a) Molecular weight /10
(b) Molecular weight /5
(c) Molecular weight /2
(d) Molecular weight
14. 1.520 g of the hydroxide of a metal on ignition gave 0.995 gm of oxide. The equivalent weight of metal is
(a) 1.520 (b) 0.995
(c) 19.00 (d) 9.00

15. If we consider that 1/6, in place of 1/12, mass of carbon atom is taken to be the relative atomic mass unit, the mass of one mole of a substance will
(a) Decrease twice
(b) Increase two fold
(c) Remain unchanged
(d) Be a function of the molecular mass of the substance
16. One gram of hydrogen is found to combine with 80g of bromine one gram of calcium valency=2 combines with 4g of bromine the equivalent weight of calcium is
(a) 10 (b) 20
(c) 40 (d) 80
17. 4.4gm of an unknown gas occupies 2.24L of volume at standard temperature and pressure. The gas may be

(a) Carbon dioxide
(b) Carbon monoxide
(c) Oxygen
(d) Sulphur dioxide


18. The number of moles of oxygen in 1L of air containing 21% oxygen by volume, in standard conditions, is

(a) 0.186 mol (b) 0.21 mol
(c) 2.10 mol (d) 0.0093 mol

19. The volume occupied by 4.4 g of Co2 at STP is
(a) 22.4 L (b) 2.24 L
(c) 0.224 L (d) 0.1 L
SOL: (b)

20. The numbers of moles of BaCo3 which contain 1.5 moles of oxygen atoms is
(a) 0.5 (b) 1
(c) 3 (d) 2

SOL: (a)
21. If two compounds have the same empirical formula but different molecular formula, they must have
(a) Different percentage composition
(b) Different molecular weights
(c) Same viscosity
(d) Same vapour density
SOL:  (b) Based on facts.

22. In which of the following pairs of compounds the ratio of C, H and O is same
(a) Acetic acid and methyl alcohol
(b) Glucose and acetic acid
(c) Fructose and sucrose
(d) All of these
SOL:  (b)

23. What quantity of ammonium sulphate is necessary for the production of NH3 gas sufficient to neutralize a solution containing 292 g of HCl?
(a) 272 g (b) 403 g
(c) 528 g (d) 1056 g
SOL:  (c)

24. If 1and1/2 moles of oxygen combine with Al to form  the weight of Al used in the reaction is (Al=27)
(a) 27 g (b) 54 g
(c) 49.5 g (d) 31 g
SOL:  (b)
25. Mohr's salt is dissolved in dil. H2SO4 instead of distilled water to
(a) Enhance the rate of dissolution
(b) Prevent cationic hydrolysis
(c) Increase the rate of ionisation
(d) Increase its reducing strength


26. Acidified potassium permanganate solution is decolourised by
(a) Bleaching powder
(b) White vitriol
(c) Mohr's salt
(d) Microcosmic salt
SOL:  (c)

27. Equivalent weight of KMnO4  acting as an oxidant in acidic medium is
(a) The same as its molecular weight
(b) Half of its molecular weight
(c) One-third of its molecular weight
(d) One-fifth of its molecular weight

28. In the preceding question, the amount of Na2CO3 present in the solution is
(a) 2.650 g (b) 1.060 g
(c) 0.530 g (d) 0.265 g
SOL: (c)

29. How many ml of 1 (M) H2SO4  is required to neutralise 10 ml of 1 (M) NaOH solution
(a) 2.5 (b) 5.0
(c) 10.0 (d) 20.0

SOL:  (b)

30. What volume of Hydrogen gas, at 273 K and 1 atm pressure will be consumed in obtaining 21.6 g of elemental boron (atomic mass = 10.8) from the reduction of boron trichloride by Hydrogen
(a) 22.4 L (b) 89.6 L
(c) 67.2 L (d) 44.8 L
SOL:  (c)

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