An IB Periodic Table is required

Calculators should not be used for multiple choice questions!

1. A sample of an oxide of sulfur was analysed and found to contain 1.6g of sulfur and 2.4g of oxygen. What is its empirical formula?

• A.   S2O3
• B.   SO3
• C.   SO2
• D.   S2O
2. Metal X forms an oxide which contains 32% by mass of oxygen. Metal X has a relative atomic mass of 51. What is the empirical formula of the oxide?
• A.   XO2
• B.   X2O
• C.   XO3
• D.   X2O3

3. What is the empirical formula of a compound containing 79.9% by mass of carbon and 20.1% by mass of hydrogen?

• A.   CH2
• B.   CH3
• C.   CH4
• D.   C2H3
4. Melamine has an empirical formula of CH2N2 and its molecular mass is 126 g mol-1. What is the molecular formula of melamine? • A.   CH2N2
• B.   C2H4N4
• C.   C3H6N6
• D.   C4H8N5
5. 5.0g of an oxide of chromium was formed from 2.6g of chromium. What is the empirical formula of this oxide?
• A.   CrO
• B.   CrO3
• C.   CrO6
• D.   Cr2O3

6. Which of the following compounds has/have the empirical formula CH2O?

 I. C6H12O6 II. CH3COOH III. C12H24O11
• A.   I only
• B.   I and II only
• C.   II and III only
• D.   I, II and III
7. 4.80g of element Y combines with exactly 1.60g of oxygen to form a compound of formula Y2O. What is the relative atomic mass of Y?
• A.   24.0
• B.   32.0
• C.   48.0
• D.   64.0
8. How many moles of water of crystallization are combined with each mole of calcium sulfate if 2.72g of anhydrous calcium sulfate (Mr = 136g mol-1) is formed when 3.44g of hydrated calcium sulfate is heated to constant mass?
• A.   1
• B.   2
• C.   3
• D.   4
9. What is the empirical formula of a hydrocarbon which produced 4.40g of carbon dioxide and 2.70g of water on complete combustion?
• A.   CH
• B.   CH2
• C.   CH3
• D.   C2H3
10. Which of the following compounds, used in the production of fertilizers, has the highest percentage by mass of nitrogen? • A.   NH3
• B.   NH4NO3
• C.   CO(NH2)2
• D.   (NH4)2SO4