Chapter 5- Chemical formula

Question 1

What are the state symbols?

Answer 1

(s) - solid
(l) - liquid
(g) - gas
(aq) - aqueous, dissolved in solution(water)

Question 2

How do you calculate the empirical formula?

Answer 2

It is the simplest whole number ratio of atoms in a compound.

Contains 10g Hydrogen and 80g Oxygen
amount H= mass(g)/Ar of H= (10/1)=10 mol
amount O=mass(g)/Ar of O=(80/16)=5 mol
ration of 10:5 and 2:1 in simplest form
so the formula is H2O

Question 3

How do you calculate the molecular formula?

Answer 3

The exact number of each atoms present in the formula of the compound.

benzene- CH
Mr-78
Empirical formula mass- (12+1)=13
Mr/ Empirical formula mass (78/13)=6
There for the molecular formula is 6 time the empirical-  C6H6

Question 4

What is the equation for concentration of a solution?

Answer 4

Amount dissolved substance(mol)=volume of solution(cm^3)x concentration solution(mol/dm)/ 1000

Question 5

What is the calculation for percentage yield?

Answer 5

yield obtained/theoretical yield x 100