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CHEMISTRY I FOUNDATION FAC0015 SEMESTER JANUARY 2014

TUTORIAL 2 (CHAPTERS 3 & 4)

1. Convert these descriptions into balanced equations:

a. When hydrogen sulfide gas is passed over hot solid iron(III) hydroxide, the resultant reaction

produces iron(III) sulfide and gaseous water.

b. When solid potassium chlorate is heated, it decomposes to form solid potassium chloride and

oxygen gas.

c. Boron sulfide, B2S3(s) reacts violently with water to form dissolved boric acid, H3BO3, and

hydrogen sulfide gas.

d. Copper metal reacts with hot concentrated sulfuric acid solution to form aqueous copper (II)

sulfate, sulfur dioxide gas and water.

2. a. What is the molar mass of cholesterol if 0.00105 mol weighs 0.406 g?

b. How many moles of chloride ions are in 0.0750 g of aluminium chloride?

c. How many moles of ammonium ions are in 4.97 g of ammonium carbonate?

d. What is the mass, in grams, of 6.52 1021

molecules of aspirin, C9H8O4?

3. The molecular formula of allicin, the compound responsible for the characteristic smell of garlic, is

C6H10OS2.

a. What is the molecular weight of allicin?

b. What is the molar mass of allicin?

c. How many moles of allicin are present in 5.00 mg of this substance?

d. How many molecules of allicin are in 5.00 mg of this substance?

e. How many S atoms are present in 5.00 mg of allicin?

4. a. What is the percentage of copper in copper(I) sulfide, Cu2S?

b. What is the mass percentage of oxygen, O in mineral leadhillite, Pb4(SO4)(CO3)2(OH)2?

c. What is the number of atoms in 0.10 mol dimethylhydrazine, (CH3)2N2H2?

5. Reductic acid contains 52.63% carbon, 5.30% hydrogen, and 42.07% oxygen. Determine the molecular

formula of the acid if the molar mass is 114 g/mol.

6. A 0.1005 g of menthol is combusted producing 0.2829 g of CO2 and 0.1159 g of H2O. What is the

empirical formula of menthol? If menthol has molar mass of 156 g/mol, what is the molecular

formula?

7. Solutions of sodium carbonate and silver nitrate react to form solid silver carbonate and a solution of

sodium nitrate. A solution containing 5.00 g of sodium carbonate is mixed with one containing 5.00 g

of silver nitrate. After the reaction is complete, the solutions are evaporated to dryness, leaving a

mixture of salts. How many grams of sodium carbonate, silver nitrate, silver carbonate and sodium

nitrate present after the reaction is complete?

8. An oxybromate compound, KBrOx, where x is unknown, is analysed and found to contain 52.92

percent Br. What is the value of x?

9. Identify the following if they are strong electrolytes, weak electrolytes or non electrolytes and write the

dissolution equation if any:

a. CH3OH (methanol)

b. ZnCl2

c. HClO4

d. HClO (hypochlorous acid)

e. NH4Cl

f. Ca(OH)2

g. HCHO2 (formic acid)

h. CH3COOH (acetic acid)

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10. Write the balanced molecular equations and net ionic equations (if any) for the following reactions:

a. Tin (II) nitrate and sodium hydroxide

b. Na2S + Cu(C2H3O2)2

c. Chromium (III) sulfate and ammonium carbonate

d. Cu(OH)2(s) and HClO4(aq)

11. Potassium chloride, KCl reacts with silver nitrate, AgNO3 in aqueous solution to yield a precipitate and

a colourless solution. Calculate the amount (in grams) of the precipitate formed when 55.00 mL of

0.350 M of KCl is mixed with 100.00 mL of 0.125 M of AgNO3.