## A 0.24 g sample of compound of oxygen and boron was found by analysis to contain 0.096 g of boron and 0.144 g of oxygen. Calculate the percentage composition of the compound by weight.

Q.1:- A 0.24 g sample of compound of oxygen and boron was found by analysis to contain 0.096 g of boron and 0.144 g of oxygen. Calculate the percentage composition…

## Which has more number of atoms, 100 grams of sodium or 100 grams of iron (given atomic mass of Na = 23 u, Fe = 56 u) ?

Q.:- Which has more number of atoms, 100 grams of sodium or 100 grams of iron (given atomic mass of Na = 23 u, Fe = 56 u) ?  …

## If one mole of carbon atoms weighs 12 gram, what is the mass (in gram) of 1 atom of carbon?

Q.:- If one mole of carbon atoms weighs 12 gram, what is the mass (in gram) of 1 atom of carbon?   Answer:- Molecular mass of carbon = 12 g…

## Calculate the formula unit masses of ZnO, Na2O, K2CO3. Given atomic masses of Zn = 65 u, Na = 23 u, K= 39 u, C =12 u and O = 16 u.

Q.:- Calculate the formula unit masses of ZnO, Na2O, K2CO3. Given atomic masses of Zn = 65 u, Na = 23 u, K= 39 u, C =12 u and O…

## Calculate the molecular masses of H2, O2, Cl2, CO2, CH4, C2H6, C2H4, NH3, CH3OH.

Q.:- Calculate the molecular masses of H2, O2, Cl2, CO2, CH4, C2H6, C2H4, NH3, CH3OH.   Answer:- Molecular mass of  H2 = 2 X atomic mass of  H = 2 X…

## How many atoms are present in a (i) H2S molecule and (ii) PO43- ion?

Q.:- How many atoms are present in a (i) H2S molecule and    (ii) PO43- ion?   Answer:- (i) 3 atoms because H2S molecule has two atoms of hydrogen and one…

## What is meant by the term chemical formulae?

Q.:- What is meant by the term chemical formula?   Answer:- The chemical formula of a compound is a symbolic representation of its composition. e.g. formula of calcium oxide. Thus,…

## Write down the names of compounds represented by the following formulae: (i)Al2(SO4)3 (ii)CaCl2 (iii)K2SO4 (iv)KNO3 (v)CaCO3

Q.:- Write down the names of compounds represented by the following formulae: (i)Al2(SO4)3 (ii)CaCl2 (iii)K2SO4 (iv)KNO3  (v)CaCO3   Answer:- (i) Aluminium sulphate (ii) Calcium chloride (iii) Potassium sulphate (iv) Potassium…