### 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