Question

Dry air is passed over hot copper until all the oxygen has reacted. copper dry air heat The volume of gas at the end of the reaction is 120 cm? What is the starting volume of dry air? A 132 cm3 B 152 cm C 180 cm D 570 cm​

Answer 1

Answer:

Dry air is passed over hot copper until all the oxygen has reacted. copper dry air heat The volume of gas at the end of the reaction is 120 cm? What is the starting volume of dry air? A 132 cm3 B 152 cm C 180 cm D 570 cm

Explanation:

Dry air is passed over hot copper until all the oxygen has reacted. copper dry air heat The volume of gas at the end of the reaction is 120 cm? What is the starting volume of dry air? A 132 cm3 B 152 cm C 180 cm D 570 cm

Answer 2

Given, Dry air is passed over hot copper until all the oxygen has reacted.

We know that dry air has 20% oxygen

Let the volume of dry air at the beginning be x

$\therefore$ The volume of oxygen at the beginning $=\frac{20x}{100}$

When all the oxygen is used up, the volume remaining is 80%

Given the volume of gas at the end of the reaction $=120 cm^{3}= \frac{80x}{100}$

$\therefore x = \frac{120 \times 100}{80}=150 cm^{3}$

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