Question

(0)
When 4.9g of KCIO3, is heated then 1.94 gram of Oxygen and 2.96 g of KClis formed.
(a) Which law of chemical combination is obeyed by above data?
(b) Give the statement of the Law.​

Answer 1

Answer:It is the low of conservation of mass

Statement - mass can neither be crated nor be destroyed

Explanation: bcoz mass of the reactant = addition of the mass of the product

Answer 2

Answer:

(b)According to the 'Law of conservation of mass', the mass of reactant side is equal to the mass of product side.

Explanation:

(a)Answer : This reaction follow 'Law of conservation of mass'.

Solution : Given,

Mass of potassium chlorate = 4.90 g

Mass of oxygen = 1.92 g

Molar mass of oxygen = 32 g/mole

Molar mass of potassium chlorate = 122.55 g/mole

Molar mass of potassium chloride = 74.55 g/mole

The balanced chemical reaction is,

2KClO_3 \overset{\Delta}{\rightarrow}2KCl+3O_2

Step 1 : First we have to calculate the moles of potassium chlorate.

\text{ Moles of } KClO_3=\frac{\text{ mass of } KClO_3}{\text{ molar mass of } KClO_3} = \frac{4.9g}{122.55g/mole}=0.0399moles

Step 2 : Now we have to calculate mass of O_2.

From the balanced chemical reaction, we conclude that

2 moles of potassium chlorate produced 3 moles of oxygen

and 0.0399 moles of potassium chlorate produced [\frac{3moles}{2moles}\times 0.0399moles] moles of oxygen

The moles of oxygen produced = 0.05985 moles

The mass of oxygen produced = Number of moles of oxygen × Molar mass of oxygen = 0.05985 moles × 32 g/mole = 1.9152 g

Step 3 : Now we have to calculate the mass of KCl.

From the balanced chemical reaction, we conclude that

2 moles of potassium chlorate produced 2 moles of KCl

and 0.0399 moles of potassium chlorate produced [\frac{2moles}{2moles}\times 0.0399moles] moles of KCl

The moles of KCl produced = 0.0399 moles

The mass of KCl produced = Number of moles of KCl × Molar mass of KCl = 0.0399 moles × 74.55 g/mole = 2.974 g

According to the 'Law of conservation of mass', the mass of reactant side is equal to the mass of product side.

The mass of reactant side = mass of potassium chlorate = 4.90 g

The mass of product side = mass of KCl + mass of oxygen = (1.9152 + 2.974)g = 4.889 g ≈ 4.9 g

Thus, we conclude that the mass of reactant is equal to the mass of product.

Hence, this reaction follow the 'Law of conservation of mass'.