Mole Concept and Avogadro's Number

Q.

Number of gram atoms of oxygen present in $0.3mole$ of $(COOH{)}_2.2H_{2}O$ is

1. 9

2. 0.9

3. 18

4. 1.8

Q. A. Give one word or a phrase for the following. [2 marks]
(i) The energy released when an electron is added to a neutral gaseous isolated atom to form a negatively charged ion.
(ii) The amount of any substance that contains $6.023\times {10}^{23}$ particles.

B. How will you distinguish between ammonium hydroxide and sodium hydroxide using copper sulphate solution? [2 Marks]

C. Give a reason for each of the following. [3 marks]
(i) Ionic compounds have a high melting point.
(ii) The blue colour of aqueous copper sulphate solution fades when it is electrolysed using platinum electrodes.
(iii) Conductivity of dilute hydrochloric acid is greater than that of acetic acid.

D. Arrange the following as per the the instruction given in the brackets: [3 marks]
(i) 50 cc of ${\text{SO}}_2$, 100 cc of ${\text{N}}_2$, 150 cc of ${\text{O}}_2$ (In increasing order of number of molecules at STP)
(ii) $K^{+},{\mathrm{Al}}^{3+},{\mathrm{Cu}}^{2+}$(In the increasing order of discharge at the cathode)
(iii) Na, K, Li (In the increasing order of atomic size)

Q.

1 mol of $C{H}_4$ contains

1. 4 g atom of Hydrogen

2. 3.0 g of carbon

3. $1.81\times {10}^{23}$ molecules of $C{H}_4$

4. $6.02\times {10}^{23}$ atoms of H

Q.

Which of the following has highest mass

1. 50 g of iron

2. 5 moles of nitrogen

3. 1 g atom of silver

4. atoms of carbon

Q. Mass of a mole of electrons is :

1. 0.20 mg
   
2. 0.02 mg
3. 0.55 mg
   
4. 1.00 mg
   

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 total mass of ${10}^{22}$ molecular units of $CuS{O}_4.5H_{2}O$ is nearly

1. 4.144 g

2. 4.5 g

3. 41.45 g

4. 24.95 g

Q.

What is the molecular mass of a substance, each molecule of which contains 9 carbon atoms, 13 hydrogen atoms and $2.33\times {10}^{-23}g$ of other component?

1. 135.04
2. 100
3. 111
4. 28

Q.

$8g$ of $O_2$ has the same number of atoms as

1. 14 g of CO

2. 22 g of CO2

3. 44 g of CO2

4. 7 g CO

Q. Avogadro’s number represents the number of atoms in

1. 32g of sulphur
2. 12.7g of iodine
3. 32g of oxygen
4. 12g of C -12