Stoichiometric Relation

Q. From 320 mg. of $O_2$, $6.023\times {10}^{20}$ molecules are removed, the no. of moles remained are

1. Zero

2. 9 X 10-2 moles

3. 3 X 10-3 moles

4. 9 x 10^-3 moles

Q.

Calculate the mass of lime obtained by heating 200g of 95% pure limestone.

1. 108.3g

2. 110.3g

3. 100g

4. 106.4g

Q. molecules of oxygen are required for complete combustion of 1 mole of acetylene (C2H2).

1. $6.022\times {10}^{23}$
2. $12.044\times {10}^{23}$
3. $15.055\times {10}^{23}$
4. $20.11\times {10}^{23}$

Q.

How many Hydrogens are their in $4{\mathrm{H}}_2\mathrm{O}$ ?

Q.

The total weight of ${10}^{22}$ molecular units of $CuS{O}_{4}5H_{2}O$ is nearly

1. 41.45 g

2. 4.144 g

3. 4.5 g

4. 24.95 g

Q. The mass of CaO that would be obtained by heating 20 kg of $90\%$ pure lime stone is:

1. 
2. 
3. 
4. 

Q. The number of molecules in $2.5$ moles of water is:

1. $6.023\times {10}^{23}$ molecules
2. $15\times {10}^{23}$ molecules
3. $2.012\times {10}^{23}$ molecules
4. $12.046\times {10}^{23}$ molecules

Q.

How many molecules of oxygen are required for complete combustion of 1 mole of acetylene $\left(C_2{H}_2\right)$?

1. 

2. 

3. 

4. 

Q. (a)
A gas cylinder contains $12\times {10}^{24}$ molecules of oxygen gas. If Avogadro's number is $6\times {10}^{23}$; Calculate:
(i) the mass of oxygen present in the cylinder.
(ii) the volume of oxygen at S.T.P. present in the cylinder. [O=16]
[2]

(b) A gaseous hydrocarbon contains 82.76% of carbon. Given that its vapour density is 29, find its molecular formula. [C=12, H=1]
[3]

(c) The equation $4N{H}_3+5O_2\to 4NO+6H_{2}O$, represents the catalytic oxidation of ammonia. If 100 $c{m}^3$ of ammonia is used calculate the volume of oxygen required to oxidise the ammonia completely.
[3]

(d) By drawing an electron dot diagram show the formation of Ammonium Ion [Atomic No.: N = 7 and H = 1]
[2]

Q. Calculate the mass of the following.

Q. Find out the number of molecules in $2.5$ moles of water.

1. $2.5N_A$
2. $10N_A$
3. $20N_A$
4. $25N_A$

Q. The mass of lime obtained by heating 200g of 95% pure limestone is .

1. 100 g
2. 108.3 g
3. 106.4 g
4. 110.3 g

Q.

Determine the number of molecules in water which has weight 50 gms.

1. $16.7\times {10}^{23}$

2. $4\times {10}^{24}$

3. $5\times {10}^{11}$

4. $4\times {10}^{23}$

Q.

The mass of Fe converted to its oxide $F{e}_3{O}_4$ by the action of 18 g of steam is:

1. 42 mg

2. 42 g

3. 24 g

4. 24 mg

Q.

The mass of Fe converted to its oxide $F{e}_3{O}_4$ by the action of 18 g of steam is:

1. 42 g
2. 42 mg
3. 24 g
4. 24 mg

Q. $112.0$ mL of ${NO}_2$ at STP was liquefied, the density of the liquid being $1.15$ $g{mL}^{-1}$. Calculate the volume and the number of molecules in the liquid ${NO}_2$.

1. $0.10$ mL and $3.01\times {10}^{22}$
2. $0.20$ mL and $3.01\times {10}^{21}$
3. $0.40$ mL and $6.02\times {10}^{21}$
4. $0.20$ mL and $6.02\times {10}^{23}$

Q. molecules of oxygen are required for complete combustion of 1 mole of acetylene (C2H2).

1. $6.022\times {10}^{23}$
2. $12.044\times {10}^{23}$
3. $15.055\times {10}^{23}$
4. $20.11\times {10}^{23}$

Q.

How much sugar will be required if each person on earth is given $100$ molecules of sugar, if the population of earth is taken to be $3\times {10}^{10}$?

1. 

2. 

3. 

4. 

Q. Comment on the physical state of group $17$ elements.

Q. What is the number of molecules present in $5$ liters of carbon dioxide at $STP$?

1. $1.344\times {10}^{23}$ molecules
2. $6.022\times {10}^{23}$ molecules
3. $6.022\times {10}^{20}$ molecules
4. $1.344\times {10}^{20}$ molecules

Q.

10g of Fe powder was mixed with a $CuS{O}_4$ solution which contained 70g of $CuS{O}_4$. What is the weight of the copper obtained?

[Fe = 55.85g Cu = 63.6g]

1. 10.39

2. 11.39

3. 12.39

4. 13.39

Q. The weight of one molecules of water is approximately:

1. 18
2. $3\times {10}^{-23}$
3. $3\times {10}^{23}$
4. $18\times 22.4$

Q. The weight of a molecule of the compound $C_{60}{H}_{122}$ is

1. $1.4\times {10}^{-21}g$
2. $1.09\times {10}^{-21}g$
3. $5.025\times {10}^{23}g$
4. $16.023\times {10}^{23}g$

Q. How many molecules are present in 1g of hydrogen?

1. $6.02\times {10}^{23}$
2. $6.02\times {10}^{22}$
3. $3.01\times {10}^{23}$
4. $1.50\times {10}^{23}$

Q.

Determine the number of molecules in water which has weight 50 gms.

1. $16.7\times {10}^{23}$

2. $4\times {10}^{24}$

3. $5\times {10}^{11}$

4. $4\times {10}^{23}$

Q.

10g of Fe powder was mixed with a $CuS{O}_4$ solution which contained 70g of $CuS{O}_4$. What is the weight of the copper obtained?

[Fe = 55.85g Cu = 63.6g]

1. 11.39

2. 10.39

3. 13.39

4. 12.39

Q. The mass of lime obtained by heating 200g of 95% pure limestone is .

1. 100 g
2. 108.3 g
3. 106.4 g
4. 110.3 g

Q.

(a) What do you mean b stoichiometry?
(b) Define atomicity of a gas. State the atomicity of Hydrogen, Phosphorus and Sulphur.
(c) Differentiate between $N_2$ and 2N.