SCIENCE DEPARTMENT: GRADE 11 CHEMISTRY EXAM

DATE: NAME: ___________________

SUBJECT: SCH 3AO CHEMISTRY TIME:

SECTIONS:

* * * * * * * * * * ** * * * * * * * * * * * * * * * * * * *

1. Answer all questions in the space provided in the exam booklet.

2. Show complete solutions to all questions involving calculations in order to obtain part marks.

3. An electronic calculator is permitted. A periodic table is provided for your use. Please do not write on it. Return it with your exam.

4. HELPFUL INFORMATION

Activity Series

Ideal Gas Constant 8.314 kPa.L

mol.K Li

K

Avogadro's Number 6.02 x 10²³ Ca

Na

Ideal Gas Law PV = nRT Mg

Al

Molar Volume of a Gas 22.4L Zn

Fe

Ni

Sn

Pb

Cu

Hg

Ag

Au

EXAM SUMMARY

UNIT MARKS

1. Matter and Atomic Theory ......... 13 2. Elements and Chemical Bonding ......... 22

3. Gases ......... 15

4. Chemical Reactions ......... 27

5. Chemical Reactions - Calculations …..... 13

6. Solutions ......... 17

7. Laboratory Work ......... 8 TOTAL MARKS........115

UNIT 1: Matter and Atomic Theory 13 MARKS

1. A small sample of sulfur was placed in a glass tube along with an equal amount of powdered zinc. The sulfur is a yellow solid with a characteristic odour, whereas the zinc is a dull grey solid. After shaking the contents of the test tube, it was slowly heated. At 94oC the sulfur portion began to melt, and then suddenly, there was a flash of light, some smoke appeared and a greyish-white ash was left in the tube. With specific reference to this experiment, give an example of:

a) a physical change:

b) a chemical change:

c) an element:

d) a compound:

e) a mixture:

f) a quantitative physical property:

2. Zinc oxide was prepared from zinc metal by three differentmethods with the following results:

Amount of Zinc Amount of Zinc Oxide

i) 4.5 g 5.605 g

ii) 3.0 g 3.738 g

iii) 6.0 g 7.476 g

a) Define the Law of Definite Proportions:

b) How do the results above demonstrate the Law of Definite Proportions?

3. Fill in the chart below for P-31

number of protons
number of neutrons
number of electrons
electron configuration
a possible isotope

UNIT I (CONT'D)

4. Complete the following table: (You may use point form)

THEORY	MAIN POINT	IMPROVEMENT OVER PREVIOUS THEORY	PROBLEM WITH THEORY
DALTON	ATOMS ARE SPHERES	BASED ON EXPERIMENTAL EVIDENCE	DISCOVERY OF ELECTRONS
RUTHERFORD
BOHR

5. Which element has 2 electrons in the first energy level, 8 electrons in the second energy level, and 7 electrons in the third energy level?

______________________

6. CIRCLE the electron configuration that does NOT correspond to an element in Group 1:

a) 1s2 2s1

b) 1s2 2s2 2p6 3s1

c) 1s2 2s2 2p6 3s2 3p64s1

d) 1s2 2s2 2p6 3s2 3p6 3d9 4s1

e) 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 5s1

UNIT II: ELEMENTS AND CHEMICAL BONDING 22 MARKS

1. From the following list of elements:

Lithium, Beryillium, Boron, Carbon, Nitrogen, Oxygen, Fluorine, Neon, Gold, Cerium, Thorium,

Choose:

a) a halogen ________________________________

b) an inert gas _____________________________

c) an alkali metal___________________________

d) a lanthanon ______________________________

2. Which of the following elements requires the least amount of energy to remove an electron from an atom to form an ion? Circle your choice.

a) O b) He c) K d) H

UNIT II (CONT'D)

3. Describe and explain the trend in atomic radius as you move across the periodic table in period

2. (Li, Be, B, C, N, O, F, Ne)

4. a) An element X has three occupied energy levels containing 2, 8, and 2 electrons. What

would be the charge on the most stable ion of element X?

___________

b) Explain your answer.

c) Explain how and why ionization energy is related to atomic size.

5. Write electron dot diagrams for:

a) silicon b) scandium

6. Show the steps involved in the formation of the ionic compound barium chloride from the

elements barium and chlorine.

7. Draw the structural formulas for each of the following:

a) N₂ b) CCl₄

8. From the following list:

CCl4 HBr C2H4 Cl2 BeO H2O

a) Select the substance with the most polar covalent bond. _________________________

UNIT II (CONT'D)

b) Select a substance with a pure covalent bond._______________

c) Select a substance that is ionic.___________________________

9. Circle the statement about ionic compounds that is false:

a) They have low melting points.

b) They have high boiling points.

c) When dissolved in water they produce a solution that conducts electricity.

d) They conduct electricity when molten.

e) They consist of cations and anions held together by electrostatic forces.

10. Which of the following elements is the most electronegative?

Circle your answer.

a) antimony, Sb b) arsenic, As c) phosphorus, P

d) sulfur, S e) chlorine, Cl

UNIT III: GASES 15 MARKS

1. At Marvin the Mole's birthday party, there were 150 helium filled balloons. What volume would the helium occupy at 15 000kPa (a typical steel tank storage pressure)? Assume each filled balloon occupies 3.5L of space, air pressure is 102kPa and the temperature in the tank is the same as in the room.

UNIT III (CONT'D)

2. Find the volume of 0.838 g of krypton gas at STP.

3. An unknown monatomic gas Y has a density of 3.43 g/L at 25oC and 101.3kPa pressure. Calculate the molar mass of the gas and determine its identity.

4. Use the Kinetic Molecular Theory to explain:

a) why it is much easier to compress gases than solids or liquids.

b) Boyle's Law

UNIT IV: CHEMICAL REACTIONS 27 MARKS

1. Name the following compounds:

a) NaF _______________________

b) (NH₄)₂S _______________________

c) Ca₃(PO₄)₂ _______________________

d) Cu(NO₃)₂ _______________________

e) CO₂ _______________________

f) MgSO₄.7H₂O_______________________

2. Write the chemical formula for the following:

a) nitrogen trioxide _____________________

UNIT IV (CONT'D)

b) mercury(II)oxide _____________________

c) chlorine gas _____________________

d) copper(II)sulfate pentahydrate_____________________

e) ammonium chlorate _____________________

f) sodium hydroxide _____________________

3. Balance the following reactions:

a) C₂H₂ + O₂ ----> H₂O + CO₂

b) CaCO₃ + HCl ----> CaCl₂ + CO₂ + H₂O

c) C₂H₅OH + O₂ ----> CO₂ + H₂O

4. Calculate the following:

a) the mass, in grams, of 0.250 mol of phosphorus

trichloride

b) The amount of substance, in moles, of 3.00 x 1023 atoms of magnesium.

c) The number of molecules in 1.00 g of oxygen.

5. Octane, an ingredient of high performance gasoline, has a molar mass of 114g. It has been found, on analysis, to consist of 15.7% hydrogen with the rest being carbon. Calculate the empirical and molecular formulas of octane.

6. Identify each reaction listed below as synthesis, decomposition, single displacement, double displacement, or neutralization.

a) Ba(ClO2)2(aq) + H2SO4(aq) ----> BaSO4(s) + 2HClO2(aq)______________________

UNIT IV (CONT'D

b) 4HNO₃(aq) ----> 4NO₂(g) + O₂(g) + 2H₂O(l) ________________________

c) 2Na(s) + Cl₂(g) ----> 2NaCl(s) ________________________

d) HCl(aq) + NaOH(aq) ----> H₂O(l) + NaCl(s) __________________________

e) Mg(s) + 2HCl(aq) ----> MgCl₂ + H₂(g) __________________________

7. Use the activity series to predict if the following reactions will occur. If they do occur, complete the equation. If they do not occur, write N.R.

a) Mg(s) + CuSO₄ (aq) ---->

b) Cu(s) + 2AgNO₃(aq) ---->

c) Ni(s) + MgCl₂(aq) ---->

UNIT V: CHEMICAL REACTIONS - CALCULATIONS 13 MARKS

1. For the following reaction:

4Al(s) + 3O₂(g) ----> 2Al₂O₃(s)

a) Name the reactants _________________________________________

b) What is the coefficient of Oxygen?__________________________

c) What is the ratio of Al atoms to O atoms?___________________

2. A camping lantern uses the reaction of calcium carbide, CaC₂(s) and water to produce acetylene gas, C₂H₂(g) and calcium hydroxide, Ca(OH)₂(s).

a) Write a balanced chemical equation for this reaction.

b) How many moles of water are required when 10 moles of calcium carbide are used?

UNIT V (CONT'D)

3. The average amount of energy required by the body every hour can be provided by the metabolism of 34.0 g of sucrose according to the equation:

C₁₂H₂₂O₁₁ (s) + 12 O₂ (g) ----> 12 CO₂ (g) + 11 H₂O (l)

What mass of oxygen is required to react with this mass of sucrose?

4. One of the reactions involved in the smelting of copper sulfide ores involves copper(I) oxide and copper(I) sulfide:

2 Cu₂O(s) + Cu₂S(s) ---> 6 Cu(s) + SO₂(g)

If excess copper(I) oxide is heated with 25.8 g of copper(I) sulfide,

a) calculate the theoretical yield of copper.

b) determine the percentage yield if 58.0 g of copper is actually isolated.

UNIT VI: SOLUTIONS 17 MARKS

1. A solution contains 5.85 g of sodium chloride dissolved in 5.00 x 103 mL of water. What is the concentration of the sodium chloride in mol/L?

2. How would you prepare 2.50 x 102mL of hydrochloric acid (0.10 mol/L) from 12.0 mol/L hydrochloric acid?

UNIT VI (CONT'D)

3. Predict whether the pH of an aqueous solution of each of the following will be above 7, below 7, or equal to 7:

a) acetic acid ___________ b) sugar ___________

c) ammonia ___________

4. a) What is the essential feature of the water molecule that makes it such a good solvent for ionic

compounds?

b) Explain, with the aid of a diagram, what happens as an ionic compound dissolves in water.

5. Define 3 of the following terms, as they pertain to solutions:

solute, solvent, soluble, miscible, saturated

6. Write the net ionic equation for the following reaction:

When solid zinc metal is added to a solution of copper(II) chloride, solid copper metal is formed, leaving a solution of zinc chloride.

UNIT VII: LABORATORY WORK 8 MARKS

1.a) A hydrate was heated and the differences in mass before and after heating was recorded. The data is given below:

Mass of crucible and cover 34.24 g

Mass of crucible, cover and hydrate 38.56 g

Mass of hydrate g

Mass of crucible, cover, and dehydrated

solid (first heating) 36.47 g

Mass of crucible, cover, and dehydrated

solid (second heating) 36.46 g

Mass of water lost g

Percentage by mass of water in the hydrate g

Formula of the unknown hydrate g

Use the information above, and the list of possibilities below to identify the hydrate.

POSSIBILITIES:

Na₂CO₃ . 10 H₂O

MgSO₄ . 7 H₂O

BaCl₂ . 2 H₂O