How many moles of lead (II) chloride will be formed from a reaction between 6.5g of PbO and 3.2g of HCl?

(1) 0.044                           

(2) 0.333

(3) 0.011                           

(4) 0.029

An organic compound contains carbon, hydrogen, and oxygen.
Its elemental analysis gave C, 38.7%, and H, 9.67%.
The empirical formula of the compound would be:

1. CH₃O                                   

2. CH₂O

3. CHO                                     

4. CH₄O

Volume occupied by one molecule of water (density = 1g cm^-3) is:

1. 9.0 x 10^-23 cm³

2. 6.023 x 10^-23 cm³

3. 3.0 x10^-23 cm³

4. 5.5 x10^-23 cm³

10 g of hydrogen and 64 g of oxygen were filled in a steel vessel and exploded. The amount of water produced in this reaction will be:

1. 2 mol

2. 3 mol

3. 4 mol

4. 1 mol

The number of atoms in 0.1 mole of a triatomic gas is: 
(N_A=6.02 x10²³mol^-1)

The number of water molecules is maximum in -

1. 18 molecules of water

2. 1.8 g of water

3. 18 g of water

4. 18 moles of water

When 50 mL of a 16.9 %  (w/v) solution of AgNO₃ is mixed with 50 mL of 5.8% (w/v) NaCl solution, then the mass of precipitate formed is:

(Ag = 107.8, N = 14, O = 16, Na= 23,Cl=35.5)

20.0 g of a magnesium carbonate sample decomposes on heating to give carbon dioxide

and 8.0 g magnesium oxide. What will be the percentage purity of magnesium carbonate

in the sample? (Atomic weight of Mg = 24)

1. 75

2. 96

3. 60

4. 84

If the Avogadro number N_A, is changed from 6.022 x 10²³ mol^-1 to 6.022 x 10²⁰ mol^-1 this would change: 

1. The definition of mass in units of grams.

2. The mass of one mole of carbon.

3. The ratio of chemical species to each other in a balanced equation.

4. The ratio of elements to each other in a compound.

A mixture of gases contains H₂ and O₂ gases in the ratio of 1:4 (w/w). What is the molar

ratio of the two gases in the mixture?

1. 1:4             

2. 4:1             

3. 16:1               

4. 2:1