EDUCATION SPRINT
CLASS- IX Total Marks : 80
Time : 1 hour 20 Minute
Atoms & Molecules
section A
* Choose the correct option from the given options [50]
1. An element X' has valency equal to 3. What will be its formula with carbonate ion?
(A) X2 CO3 (B) X2 (CO3 )2 (C) XCO2 (D) X2 (CO3 )3
2. 3.42g of sucrose are dissolved in 18g of water in a beaker. The number of oxygen atoms
in the solution are:
(A) 6.68 × 1023 (B) 6.09 × 1022 (C) 6.022 × 1023 (D) 6O22 × 1021
3. How many hydrogen atoms are there in a water molecule?
(A) 0 (B) 1 (C) 2 (D) 3
4. 3.42g of glucose are dissolved in 18g of water in a beaker. The number of oxygen atoms
in the solution is:
(A) 6.68 × 1023 (B) 6.09 × 1022 (C) 6.022 × 1023 (D) 6.022 × 1021
5. If 12 gram of carbon has x atoms, then the number of atoms in 12 grams of magnesium
will be:
(A) x (B) 2x (C) x
(D) 1.5x
2
6. During any chemical change, the total mass of the products is equal to the total mass of
reactants. This is a statement according to:
(A) Law of (B) Law of constant (C) Law of multiple (D) Law of reciprocal
conservation of mass composition proportion proportion
7. 1 Nanometer is equal to:
(A) 10−10 m (B) 10−9 m (C) 10−8 m (D) 10−7m
8. Which among the following has molecular mass of 36.5u:
(A) Carbon molecules (B) Hydrogen (C) Sulphur (D) Hydrochloric acid
molecules molecules
9. Which of the following is octa-atomic?
(A) Sulphur. (B) Oxygen. (C) Ozone. (D) Phosphorus.
10. Which of the following would weigh the highest?
(A) 0.2 mole of (B) 2 moles of CO2 (C) 2 moles of CaCO3 (D) 10 moles of H2 O
sucrose (C12 H 22 O,,)
11. An atom is:
(A) The smallest (B) The smallest (C) The smallest (D) Radioactive
particle of matter particle of a gas indivisible particle of emission
known an element that can
take part in a
chemical change
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12. This subatomic particle of an atom has a POSITIVE charge.
(A) Electron (B) Neutron (C) Proton (D) Amitron
13. Which of the following configuration is most likely to form an anion:
(A) 2, 6 (B) 2, 8, 1 (C) 2, 1 (D) 2, 2
14. When two molecules of hydrogen react with one molecule of oxygen, the mass of
reactants is 36, what is the mass of products:
(A) 18 (B) 36 (C) 9 (D) 32
15. Barium chloride reacts with sodium sulphate to form Barium sulphate and sodium
chloride. Then, according to the law of conservation of mass:
(A) The total mass of (B) The total mass of (C) The total mass of (D) None of the
reactants, barium reactants, barium the reactants is equal above
chloride, and sodium chloride, and sodium to the total mass of
sulphate taken is sulphate is less than products
greater than the total the total mass of
mass of products, products, barium
barium sulphate, sulphate, and sodium
sodium chloride chloride
formed
16. 0Law of conservation of mass is also known as:
(A) Law of (B) Law of mass (C) Law of (D) None of the
indestructibility action conservation of above
energy
17. Mass can neither be created nor destroyed. This is in agreement with which law of
chemical combination:
(A) Law of definite (B) Law of multiple (C) Law of (D) Law of
proportion proportion conservation of mass conservation of
momentum
18. Why is atom electrically neutral:
(A) It has same (B) It has same (C) It has same (D) None of the
number of neutrons & number of neutrons & number of protons & above
protons electrons electrons
19. One of the following elements has an atomicity of ‘one’. This element is:
(A) Helium. (B) Hydrogen. (C) Sulphur. (D) Ozone.
20. The formula of a compound is X3 Y. The valencies of elements X and Y will be
respectively:
(A) 1 and 3 (B) 3 and 1 (C) 2 and 3 (D) 3 and 2
21. Which of the following elements has the same molecular mass as its atomic mass?
(A) Nitrogen. (B) Neon. (C) Oxygen. (D) Chlorine.
22. What is the formula mass unit of ZnO?
(A) 18u (B) 81u (C) 88u (D) 188u
23. The law of conservation of mass was given by:
(A) Dalton. (B) Proust. (C) Lavoisier. (D) Berzelius.
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24. Which of the following represents a correct chemical formula?
(A) CaCl (B) BiPO4 (C) NaSO4 (D) NaS
25. Which of these would support the idea that mass is conserved in a reaction that
produces gas as a product:
(A) Heating the (B) Subtracting the (C) Mixing the (D) Trapping the gas
reactants to ensure mass of the gas from reactants and and measuring its
the reaction occurs in the mass of the solid measuring their total mass.
a gaseous state. and liquid products. mass.
26. Molecular compounds are usually formed by the combination between:
(A) A metal and a (B) Two different non- (C) Two different (D) Any two gaseous
non-metal. metals. metals. elements.
27. The symbol of copper is:
(A) Co (B) Cr (C) Cp (D) Cu
28. The chemical symbol for sodium is:
(A) So (B) Sd (C) NA (D) Na
29. A particle P has 18 electrons, 20 neutrons and 19 protons. This particle must be:
(A) A molecule. (B) A binary (C) An anion. (D) A cation.
compound.
30. Which of the following is not correctly matched ?
(A) Calcium - Ca (B) Silver - Ag (C) Gold - Au (D) Copper - Co
31. Which scientist proposed the concept of atomic mass:
(A) Avogadro (B) Gay Lussac (C) Proust (D) Dalton
32. What is the atomic mass (u) of chlorine:
(A) 34 (B) 35.5 (C) 33 (D) 35
33. _________ deduced that all kind of matter are made up of "anu".
(A) Dalton (B) Sir. J. J. Thomson (C) Kanad (D) Rutherford
34. Atomic theory was given by:
(A) John Dalton (B) Neils Bohr (C) E. Rutherford (D) Haber Bosch
35. Smallest particle of an element or a compound which is capable of independent
existence is called:
(A) Atom (B) Molecule (C) Element (D) Compound
36. Symbol of Cadmium is:
(A) Ca (B) Cd (C) C (D) Cm
37. Molecular mass of nitric acid is:
(A) 22u (B) 12u (C) 33u (D) 63u
38. An ionic compound will be formed by the combination of one of the following pairs of
elements. This pair of elements is:
(A) Chlorine and (B) Calcium and (C) Sulphur and (D) Chlorine and
calcium. sodium. carbon. chlorine.
39. All matter is made of:
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(A) Energy (B) Atoms (C) Electrons (D) Compounds
40. The molecular weight of calcium carbonate CaCO3is:
(A) 80 (B) 90 (C) 100 (D) 110
41. Which is not one of the laws of chemical combinations:
(A) Law of multiple (B) Law of (C) Law of (D) Law of definite
proportion conservation of mass conservation of proportion
energy
42. Which of the following has the maximum number of atoms?
a. 18g of H 2 O
b. 18g of O2
c. 18g of CO2
d. 18g of CH 4
43. The symbols of the elements cobalt, aluminium, helium and sodium respectively
written by a student are as follows. Which symbol is the correct one?
a. CO
b. AL
c. He
d. So
44. The formula of a compound is X3 Y. The valencies of elements X and Y will be
respectively:
a. 1 and 3
b. 3 and 1
c. 2 and 3
d. 3 and 2
45. Molecular compounds are usually formed by the combination between:
a. A metal and a non-metal.
b. Two different non-metals.
c. Two different metals.
d. Any two gaseous elements.
46. The atomic number of an element X is 13. What will be the number of electrons in its
ion X3+?
a. 11
b. 15
c. 16
d. 10
47. An ionic compound will be formed by the combination of one of the following pairs of
elements. This pair of elements is:
a. Chlorine and calcium.
b. Calcium and sodium.
c. Sulphur and carbon.
d. Chlorine and chlorine.
48. Which of the following correctly represents 360g water?
i. 2 moles of H 2 O.
ii. 20 moles 0f water.
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iii. 6.022 × 1023 molecules of water.
iv. 1.2044 × 1025 molecules of water.
a. (i)
b. (i) and (iv)
c. (ii) and (iii)
d. (ii) and (iv)
49. The law of constant phosphorus, sulphur and krypton, the elements having the lowest
and highest atomicities are respectively:
a. Sulphur and krypton.
b. Krypton and ozone.
c. Phosphorus and sulphur.
d. Krypton and sulphur.
50. The atomicities of ozone, sulphur, phosphorus and argon are respectively:
a. 8, 3, 4 and 1
b. 1, 3, 4 and 8
c. 4, 1, 8 and 3
d. 3, 8, 4 and 1
* Do as directed [5]
51. How many moles are 3.6g of water?
52. Name the elements represented by the following symbols: Hg, Pb, Au, Ag, Sn.
53. Write down the formulae of. sodium oxide.
54. Find the mass of 2 moles of oxygen atoms?
55. What is the mass of 0.2 mole of oxygen atoms?
section B
* Answer the Questions in brief [8]
1. ‘If 100 grams of calcium carbonate (whether in the form of marble or chalk) are
decomposed completely, then 56 grams of calcium oxide and 44 grams of carbon
dioxide are obtained’. Which law of chemical combination is illustrated by this
statement?
2. What is meant by the symbol of an element? Explain with examples.
3. What are (i) ionic compounds, and (ii) molecular compounds? Give two examples of each
type of compounds.
4. What is the significance of the formula H 2 O?
section C
* Answer the Questions in detail [12]
1. An element A forms an oxide A 2 O5 .
a. What is the valency of element A?
b. What will be the formula of chloride of A?
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2. Write the molecular formulae of all the compounds that can be formed by the
2+ + 3+ − 2− 3−
combination of following ions. Cu , Na , Fe , CL , SO
4
, PO
4
3. If the aluminium salt of an anion X is Al2 X3 , what is the valency of X? What will be the
formula of the magnesium salt of X?
4. Show by means of calculations that 5 moles of CO2 and 5 moles of H 2 O do not have the
same mass. How much is the difference in their masses?
section D
* Answer the Questions in detail [ 5 marks each ] [5]
1. Write the cations and anions present, if any, in the following:
a. CH 3 COONa
b. NaCl
c. H2
d. NH 4 NO3
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