Percentage Composition

Q.

The composition of a sample of wustite (ore of Fe) is $F{e}_{0.93}$ $O_{1.00}$. What percentage of the iron is present in the form of Fe(III)?

1. 

2. 

3. 

4. 

Q.

$\mathrm{KBr}$ is doped with 10^-5 mole per cent of SrBr₂. The number of cationic vacancies in 1 g of $\mathrm{KBr}$ crystal is___ 10¹⁴. (Round off to the Nearest Integer).

Q. Determine tge percentage composition of a mixture of anhydrous sodium carbonate and sodium bicarbonate from the following data : weight of mixture taken = 2g loss in weight on heating = 0.11

Q.

1.24 gm P is present in 2.2 gm of

1. P₄S₃

2. P₂S₂

3. PS₂

4. P₂S₄

Q.

The heat of combustion of ethylene at ${18}^{\circ }C$ and at constant volume is -335.8 K cal when water is obtained in liquid state. What is the heat of combustion at constant pressure and at ${18}^{\circ }C$.

1. 337 k cal

2. 237 k cal

3. -237k cal

4. -337 k cal

Q. The mass percentage of phosphorus in $H_{3}P{O}_4$ is:

1. $22.22\%$
2. $31.63\%$
3. $28.57\%$
4. $45\%$

Q.

A solution is prepared by adding 2 g of a substance A to 18 g of water. Mass percent of solute A will be:

1. 15%

2. 10%

3. 20%

4. 25%

Q. Percentage composition of hydrogen in benzene ($C_6{H}_6$) is :

1. $8\%$
2. $7.7\%$
3. $50\%$
4. $5\%$

Q.

A 5 litre flask contains 3.5gm of $N_2$, 3g of $H_2$ and 8g of $O_2$ at 27${}^{\circ }$C.Find the total pressure exerted by the mixture of these gases.

1. 92.4 atm

2. 0.924 atm

3. 9.24 atm

4. 924 atm

Q. Silver nitrate is gradually added to an aqueous solution containing 0.01 M each of chloride , bromide and iodide ions. The decreasing order in which the halides will be precipitated is?

Q.

Calculate the empirical and molecular formula of an organic compound whose percentage composition is Carbon =70.54%, Hydrogen=5.94%, 23.52%.

The molecular weight of the compound is 136?

Q. The crystalline salt $N{a}_{2}S{O}_4.x{H}_{2}O$ on heating loses 55.9% of its mass and becomes anhydrous. The formula of the crystalline salt is:

1. $N{a}_{2}S{O}_4.5H_{2}O$
2. $N{a}_{2}S{O}_4.7H_{2}O$
3. $N{a}_{2}S{O}_4.2H_{2}O$
4. $N{a}_{2}S{O}_4.10H_{2}O$

Q.

Molarity of $H_{2}S{O}_4$ is 18 M. Its density is 1.8 $g/c{m}^3$ hence molality is

1. 18

2. 100

3. 36

4. 500

Q. Whatis the relationship between normality and mass percent

Q.

A milkman mixes milk and water in the ratio $5:2$. What percentage of the mixture is water?

Q. Two elements $X$ and $Y$ (atomic mass of $X=75\text{u}$, $Y=16\text{u}$) combine to give a compound that has 76% of $X$. The formula of the compound is:

1. $XY$
2. $X_{2}Y$
3. $X_2{Y}_2$
4. $X_2{Y}_3$

Q. Calculate average molecular weight of the mixture 25% ch4 and 75% SO2 by volumes

Q. In order to estimate the percentage of phosphorus in an organic compound, it is precipitated as Options: (NH4)3PO4 · 8MoO2 (NH4)3PO4 · 12MoO3 (NH4)2HPO3 · 12MoO3 (NH4)2HPO3 · 8MoO2

Q. The solubility of a gas in water is $0.001M$ at $STP$. Determine its Henry's law constant.

Q. how much mass of sodium acetate is required to make 250ml of 0.575 molar aqueous solution

Q. Haemoglobin contains 0.334% of iron by weight. The molecular weight of haemoglobin is approximately $67200\text{amu}$. The number of iron atoms (Atomic weight of $Fe$ is 56) present in one molecule of haemoglobin is:

1. 4
2. 6
3. 3
4. 2

Q. How to find gram equivalent mass?? Explain in detail

Q. what is the equivalent mass of Al2O3 ?

Q. 23. Calculate the percentage composition of each element in the pure sample of green vitriol

Q. Calculate the amount of $CaC{O}_3$ in grams having percentage purity $25\%$ that produces $0.56$ litre of $C{O}_2$ at STP on heating?

Q. A solution contains 2 moles of sugar. What volume of solution give rise to an osmotic pressure of $1atmat{27}^{\circ }C?$

1. $24630c{m}^3$
2. $49260c{m}^3$
3. $24.63c{m}^3$
4. $49.26c{m}^3$

Q. what is law of definite proportions?

Q. An alloy of iron (54.7%), nickel (45%) and manganese (0.3%) has a density of $8.17{\text{g/cm}}^3$. How many iron atoms are present in a block of the alloy measuring $10\text{cm}\times 20\text{cm}\times 15\text{cm}$?

1. $1.422\times {10}^{26}$
2. $1.422\times {10}^{23}$
3. $6.23\times {10}^{23}$
4. $1.656\times {10}^{26}$

Q. Briefly explain the law of multiple proportions.

Q.

A solution is prepared by adding 2 g of substance A to 18g of water.Caluculate the mass percent of the solutoin?