Chemistry - Matter and Laws of Chemical Combination

Question - 1

The solid like conducting state of gases with free electrons is called

  • A sol
  • B gel
  • C plasma
  • D All of these

Question - 2

which of the following statements about a compound is incorrect?

  • A A molecule of a compound has atoms of different elements
  • B A molecule of a compound has atoms of different elements
  • C A molecule of a compound has atoms of different elements
  • D A molecule of a compound has atoms of different elements

Question - 3

A molecule of a compound has atoms of different elements

  • A Mixture of soil and water
  • B Sugar solution
  • C Mixture of sugar, salt and sand
  • D Iodised table salt

Question - 4

In which of the following numbers all zeroes are significant?

  • A 30.000
  • B 0.700
  • C 0.00050
  • D 0.0030

Question - 5

The answer of the calculation \(\frac{2.568\times5.8}{4.168}\) in significant figures will be

  • A 3.570
  • B 3.6
  • C 3.57
  • D 3.579

Question - 6

Number of significant figures in 78.000 g, 0.0206 g and 3.002 g are

  • A 3, 4, 5
  • B 2, 5, 4
  • C 3, 3, 4
  • D 5, 3, 4

Question - 7

Law of constant composition does not hold true for

  • A endothermic compounds
  • B exothermic compounds
  • C stoichiometric compounds
  • D non-stoichiometric compounds

Question - 8

Formation of CO and CO2 illustrates the law of

  • A conservation of mass
  • B multiple proportion
  • C reciprocal proportion
  • D constant proportion

Question - 9

Which of the following reactions is not correct according to the law of conservation of mass?

  • A 2Mg(s) + O2(s) \(\rightarrow\) 2MgO(s)
  • B C3H8(g) + O2 (g) \(\rightarrow\) CO2(g) + H2O(l)
  • C P4(s) + 5O2(g) \(\rightarrow\) P4O10(s)
  • D CH4(g) + 2O2(g) \(\rightarrow\) CO2(g) + 2H2O(g)

Question - 10

One part of element A reacts with two parts of another elements B. 6 parts of element C reacts with 4 parts of element B. If A and C combine together, the ratio of their weights will be governed by

  • A law of conservation of mass
  • B law of reciprocal proportions
  • C law of definite proportions
  • D law of multiple proportions
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