Question

Which of the following illustrates the law of conservation of mass?

• A. Mixing of 10 g of sulphur and 2 g of sand does not show a change in mass
• B. The mass of platinum wire before and after heating remains constant
• C. 2.2 g of propane and 8 g of oxygen produce 10.2 g of gaseous mixture of carbon dioxide and water vapours
• D. 2.8 g of CO and 1.6 g of oxygen gives 3g of $C{O}_2$

Answer 1

The correct option is C 2.2 g of propane and 8 g of oxygen produce 10.2 g of gaseous mixture of carbon dioxide and water vapours

In the options (a) and (b), there is no chemical reaction taking place, so we cannot apply laws of chemical combination, which means that law of conservation of mass cannot be followed.
For the option (c),
2.2 + 8 = 10.2
Mass of Reactants = Mass of Products
For the option (d),
2.8 + 1.6 ≠ 3 g
4.4 g ≠ 3 g
Mass of Reactants ≠ Mass of Products

So, only option (c) follows the law of conservation of mass