Question

These are three balloons having 1mole of Oxygen gas in the 1st, 1mole of Nitrogen gas in the 2nd and 1mole of Nitrous Oxide gas in the 3rd at Standard temperature and pressure. Analyse the given image and information to suggest the volume occupied by each gas and the mass of each gas in the three different balloons. [4 M]
Ans.

Q4. Use following experimental information to determine the empirical formula of an oxide of silicon. Silicon(s) + Oxygen (g) → Silicon dioxide(s)
Mass of crucible – 18.20 g
Mass of crucible + silicon- 18.48 g
Mass of crucible + Oxide of silicon – 18.80 g

a) Outline scientific knowledge and understanding to find out the number of moles of each element.

b) Explain the use of empirical and molecular formulae.

c) Analyse the given information and determine the Empirical formula

Answer 1

Answer:

Correct option is

B

2

At STP, 1 mole of nitrous oxide occupies a volume of 22.4 L.

The atomic masses of N and O are 14 g/mol and 16 g/mol respectively.

The molar mass of nitrous oxide

N

2

O=2(14)+16=44 g/mol

Thus 44 g (1 mole) N

2

O= 22.4 L at STP.

1L N

2

O=

22.4

44

=2 L

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