Law of Conservation of Mass

Q.

According to law of conservation of mass, during a chemical reaction:

1. that matter can neither be created nor be destroyed in a chemical reaction.

2. that matter cannot be created but destroyed in a chemical reaction.

3. that matter can be created as well as destroyed in a chemical reaction.

4. that matter can be created but not destroyed in a chemical reaction.

Q.

How will you show that there is no change in mass during a chemical reaction?

Q.

What does the following statement mean? In a chemical reaction, the total mass of the reactants is equal to the total mass of the products.

1. There is no change in the mass during a chemical reaction

2. Chemical energy nullifies the mass

3. Those reactions are reversible

4. Catalysts used will make up for the lost mass

Q. If the masses of Cr and O are in ratio 13:12 in Cr03, then the ratio of O that combines with the same mass of Cr in Cr2O3 and Cr2O7 is 1)1:2 2)1:4 3)3:7 4)2:5

Q.

448 L of ammonia at STP on decomposition gives X g of nitrogen. How many molecules of oxygen are required to produce NO₂ from X g of nitrogen.

Q.

X and Y chemically react to form a new product Z.

X+Y→Z

The masses of X and Y are 5 g and 6 g respectively. The mass of Z _______ is g.

1. 11

2. 5

3. 10
4. 6

Q.

is dalton theory is the same as particle theory of matter ?

Q.

If 10 gms of $Mg$ react with 20 gms of $O_2$, then how many grams of $MgO$ is formed?

1. 15

2. 30

3. 20

4. 25