Chemistry: Practice multiple choice questions

1. How many moles of Na₃PO₄ (molar mass 164 g/mol) are there in 5.7 g of Na₃PO₄?
   1. 0.035
   2. 28.8
   3. 935
   4. 2.1 x 10²²
2. The chemical reaction:

   2HgO(s) 2Hg(l) + O2(g)

   is best described by which one of the following terms?
   1. Double decomposition
   2. Decomposition
   3. Combustion
   4. Neutralization
3. The formula of iron(III) carbonate is
   1. FeCO₃
   2. Fe(CO₃)₃
   3. Fe₂(CO₃)₃
   4. Fe₃(CO₃)₂
4. Which of the following sets of coefficients gives the correct values for the coefficients v, w, x, y, z in the following equation
   

   v

   Na2CO3(s) +

   w

   H+(aq)

   x

   Na+(aq) +

   y

   H2O(l) +

   z

   CO2(g)

   	v	w	x	y	z
   A.	1	2	1	2	2
   B.	1	2	2	2	1
   C.	1	1	1	1	1
   D.	1	2	2	1	1

5. Which one of the following is not a pure substance?
   1. Molten sodium chloride
   2. Sodium chloride solution
   3. Sodium chloride solid
   4. Sodium chloride vapour
6. Which one of the following provides the best description of an isotope?
   1. Atoms with the same number of protons but differing numbers of electrons.
   2. Atoms with the same mass number but differing atomic numbers.
   3. Atoms with the same mass numbers and the same atomic numbers.
   4. Atoms with the same atomic numbers but differing mass numbers.
7. A student wrote the following formulas for various compounds:
   1. Copper (I) chloride - CuCl
   2. Sodium chlorate - NaClO₃
   3. Lead(II) hydroxide - Pb(OH)₂
   4. Magnesium nitrate - Mg(NO₃)₂
   Which one of the following statements is true?
   1. All the formulas are correct
   2. Only I, III and IV are correct
   3. Only I, II and III are correct
   4. Only II, III and IV are correct
8. How many moles of ions are present when a solution containing 1 mole of CaCl₂ is mixed with a solution containing 1 mol NH₄NO₃, assuming that no chemical reaction takes place and that all electrolytes are strong electrolytes (fully dissociated).
   1. 2
   2. 4
   3. 5
   4. 12
9. The following equation describes the burning of hexane (C₆H₁₄) in oxygen:

   2C6H14 + 19O2 12 CO2 + 14H2O

   How many mole of water would be produced if 0.4 mole of hexane was burnt in excess oxygen?
   1. 12
   2. 6
   3. 5.6
   4. 2.8
10. How many atoms are there in 0.1 mole of ozone (O₃, molar mass 48.0 g/mol)?
    1. 6.02 x 10²²
    2. 6.02 x 10²³
    3. 1.8 x 10²³
    4. 18 x 10²³

Ans 

1. 0.035
2. Decomposition
3. Fe₂(CO₃)₃
4. _D
5. _{Sodium chloride solution}
6. _{Atoms with the same atomic numbers but differing mass numbers.}
7. _{All the formulas are correct}
8. ₅
9. _2.8
10. _{1.8 x 10²³} 
11.