Mass Percentage

Q.

Calculate the percentage composition of oxygen and hydrogen in Water ${\mathrm{H}}_2\mathrm{O}$.

Given : Atomic weight of H = 1u, O = 16u

Q.

Zinc sulphate contains $22.65\%$ of zinc and $43.9\%$ of water of crystallization. If the law of constant proportions is true, then the weight of zinc required to produce 20 g of the crystals will be

1. 45.3 g

2. 4.53 g

3. 0.453 g

4. 453 g

Q.

Calculate the percentage composition of hydrogen, sulphur and oxygen in Sulphuric acid $\left({\mathrm{H}}_2{\mathrm{SO}}_4\right)$.

Given : Atomic weight of H = 1u, S = 32u, O = 16u

Q.

Mass percentage ratio $\mathrm{C}$‘ and ’ $\mathrm{H}$‘ and ’$\mathrm{C}$‘ and ’$\mathrm{O}$ of saturated acyclic organic compound in $4:1$ and$3:4$. What is the number of moles of oxygen required for combustion for two moles of organic compound "X"?

Q.

The mass percentage of nitrogen in urea (

${NH}_2{CONH}_2$

) is .

1. 85.92
2. 46.67
3. 18.23
4. 28.58

Q.

Find the percentage of water of crystallisation in $CuS{O}_4.5H_{2}O.$ (At. Mass $Cu-64,H=1,O=16,S=32$)

Q.

Calculate the percentage composition of :
potassium chlorate, $KCl{O}_3$

Q.

Calculate the percentage composition of oxygen, nitrogen and calcium in Calcium nitrate $\left(\mathrm{Ca}{\left({\mathrm{NO}}_3\right)}_2\right)$.

Given : Atomic weight of O = 16u, Ca = 40u, N = 14u

Q.

A metal M forms a volatile chloride containing 65.5% chlorine. If the density of the chloride relative to hydrogen is 162.5, find the molecular formula of the chloride.

[M = 56, Cl = 35.5]

Given: Cl = 65.5%

M = (100-65.5)% = 34.5 %

1. M₂Cl₁₀

2. M₂Cl₃

3. M₂Cl₆

4. M₂Cl₄

Q.

Urea is a very important nitrogenous fertilizer. Its formula is $CO{N}_2{H}_4$ Calculate the percentage of nitrogen in urea (C = 12, O = 16, N = 14 and H = 1).

Q.

Calculate the percentage composition of iron and oxygen in ${\mathrm{Fe}}_2{\mathrm{O}}_3$.

Given : Atomic weight of Fe = 55.8u, O = 16u

Q.

Calculate the mole fraction, molality and molarity of HnO3 in solution containing 12.2% HnO3.Density of HnO3 is 1.038 gram cm^-3.

Q.

Barium chloride crystals contains 14.8 water fo crystallisation. Find the number of molecules fo water of crystallisation per molecule.

Q.

Calculate the percentage of platinum in ammonium chloroplatinate (NH₄)₂PtCl₆.

Q.

Name the two fertilizers containing nitrogen and containing phosphorus.

Q.

Washing soda has the formula Na₂CO₃.10H₂O. What mass of anhydrous sodium carbonate is left when all the water of crystallization is expelled by heating 57.2 g of washing soda?

1. 17.4 g

2. 14.6 g

3. 28.3 g

4. 21.2 g

5. 42.8 g

Q.

What is the percentage of nitrogen present in ammonium nitrate? (N=14, H=1, O=16)

1. $25\%$

2. $30\%$

3. $35\%$

4. $40\%$

Q.

Find the percentage of oxygen in magnesium nitrate crystals, $Mg(N{O}_3{)}_2.6H_{2}O$ [Mg = 24, N = 14, O = 16, H = 1]

1. 70%

2. 60%

3. 80%

4. 75%

Q.

Calculate the percentage of water of crystallization in ${\mathrm{CuSO}}_4.5{\mathrm{H}}_2\mathrm{O}$$\left[\mathrm{H}=1,\mathrm{O}=16,\mathrm{S}=32,\mathrm{Cu}=64\right]$

Q.

Calculate the mass of iron in 10 kg of iron ore which contains 80% of pure ferric oxide.

Q.

Calculate the percentage of Nitrogen in the fertilizer, Ammonium Nitrate $N{H}_{4}N{O}_3$

[H = 1, N = 14, O = 16]

1. 35%

2. 40%

3. 20%

4. 10%

Q.

How can you calculate the relative molecular mass and percentage composition of a compound

Q.

Percentage composition of hydrogen in benzene is _____.

1. 
2. 
3. 
4. 

Q.

Glucose $\left({\mathrm{C}}_6{\mathrm{H}}_{12}{\mathrm{O}}_6\right)$ contains ______ percentage carbon by weight.

Q.

A sample of ammonium nitrate when heated yields 8.96 litres of steam (measured at STP).

NH₄NO₃ → N₂O +2H₂O

What mass of ammonium nitrate should be heated to produce 8.96 litres of steam? (Relative molecular mass of ammonium nitrate is 80.)

1. 19 g

2. 14 g

3. 17 g

4. 16 g

5. 11 g

Q.

Salts while crystallizing out from their aqueous solution, unite with a definite quantity of water which is known as __________________.

Q. An organic compound contains $8$% oxygen and $4$% sulphur by mass. The minimum possible molecular weight of the compound is:

1. $400$
2. $200$
3. $800$
4. $1600$

Q. Calculate the percentage of phosphorus in calcium phosphate $C{a}_3{\left(P{O}_4\right)}_2$.

Q.

Find the percentage of
(a) oxygen in magnesium nitrate crystals $\left[Mg\right(N{O}_3{)}_{2}6H_{2}O]$.
(b) boron in $N{a}_2{B}_4{O}_7.10H_{2}O.[H=1,B=11,O=16,Na=23].$
(c) phosphorus in the fertilizer superphosphate $Ca(H_{2}P{O}_4{)}_2$

Q. A. (i) What is the percentage composition of calcium in calcium nitrate? [1 mark]
(ii) At 27 $°$C, a balloon is filled with 3 L air. The volume of the balloon when the temperature is 54 $°$C is . [1 mark]

B. Distinguish between the following pair of compounds based on the reagent given in the bracket. [2 marks]
(i) Ferrous sulphate solution and ferric sulphate solution. (using sodium hydroxide solution)
(ii) Dilute hydrochloric acid and dilute sulphuric acid. (using lead nitrate solution)

C. The pH value of three solutions A, B and C are given in the table.

Solution	pH Value
A	12
B	2
C	7

Answer the following questions. [3 marks]
(i) Which solution will have no effect on litmus solution?
(ii) Which solution will liberate $C{O}_2$ when reacted with sodium carbonate?
(iii) Which solution will turn red litmus solution blue?


D. Study the extract of the Periodic table given below and answer the questions. Give the aphabet correpsonding to the element. (Do not repeat the element.) [3 marks]

(i) Which element forms electrovalent compound with G?
(ii) The ion of which element will migrate towards the cathode during electrolysis?
(iii) Which non-metallic element has the valency of 2?