What do we call those particles which have more or less electrons than the normal atoms?

A liquid compound X of molecular mass 18 u can be obtained from a number of natural sources. All the animals and plants need liquid X for their survival. When an electric current is passed through 200 grams of pure liquid X under suitable conditions, then 178 grams of gas Y and 22 grams of gas Z are produced. Gas Y is produced at the positive electrode whereas gas Z is obtained at the negative electrode. Moreover, gas Y supports combustion whereas gas Z burns itself causing explosions.

(a) Name (i) liquid X (ii) gas Y, and (iii) gas Z

(b) What is the ratio to the mass of element Z to the mass of element Y in the liquid X?

(c) Which law of chemical combination is illustrated by this example?

(d) Name two sources of liquid X.

(e) State an important use of Y in our life.

One of the forms of a naturally occurring solid compound P is usually used for making the floors of houses. On adding a few drops of dilute hydrochloric acid to P, brisk effervescence are produced. When 50 g of reactant P was heated strongly, than 22 g of a gas Q and 28 g of a solid R were produced as products. Gas Q is the same which produced brisk effervescence on adding dilute HCl to P. Gas Q is said to cause global warming whereas solid R is used for white-washing.

(a) What is (i) solid P (ii) gas Q, and (iii) solid R.

(b) What is the total mass of Q and R obtained from 50 g of P?

(c) How does the total mass of Q and R formed compare with the mass of P taken?

(d) What conclusion do you get from the comparison of masses of products and reactant?

(e) Which law of chemical combination is illustrated by the example given in this problem?

What do we call those particles which have:

(a) more electrons than the normal atoms?

(b) less electrons than the normal atoms?

Define ‘formula mass’ of a compound.