CHEMISTRY 1000

End of Term Review ProblemsSummer 2007Dr. Susan Lait

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1. Each of the following reactions has at least one product that is a gas. Write a balanced chemical equation for each reaction. Include states of matter.

a) Magnesium metal is added to hydrobromic acid.

b) Calcium carbonate is added to hydrochloric acid.

c) Beryllium carbonate decomposes upon heating.

d) Sodium metal is added to water.

e) Ozone decomposes.

Reactions Producing Gases

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Reactivity of Elements

2. Complete the following table. If two elements react readily, write the product(s) in the box between the two elements. If they do not react readily, write “X”.For clarity, the first row (for the reactions of lithium) has been filled in.

Cells marked “n/a” represent chemistry not covered in CHEM 1000 and do not need to be filled in.

Cl2 O2 N2 P4 H2 Mg K Na

Li LiCl Li2O Li3N n/a X X X X

Na n/a

K n/a

Mg n/a

H2

P4

N2

O2

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3. Lead(II) arsenate has been used as an insecticide to control cockroaches, silverfish and crickets.

a) Predict the molecular formula for lead(II) arsenate.b) Assign oxidation states to the elements in lead(II) arsenate.c) Draw the Lewis dot structure of the arsenate ion.

Include formal charges on the appropriate atoms.d) Name the electron group and molecular geometries for the

arsenate ion.e) Draw the 3-dimensional shape of the arsenate ion using

wedge-and-dash notation. Label the bond angles on your diagram.

Lead(II) Arsenate

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Xenon + Fluorine = ???

4. There are three possible products of a reaction between xenon and fluorine: XeF2, XeF4 and XeF6.

a) Name the three products.b) Draw Lewis dot structures for XeF2 and XeF4.

c) Name the electron group & molecular geometries for XeF2 & XeF4.

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Xenon + Fluorine = ???

d) At 400 ˚C, a 1.00 L flask containing 640 kPa of xenon is connected to a 1.60 L flask containing 800 kPa of fluorine. The gases are allowed to mix and react completely so that no elemental xenon or fluorine remains. Identify the product, and calculate the final pressure in the connected flasks. (Assume no temperature change.)

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Atomic Orbitals

5. For each of the following orbitals: draw a picture (use x, y & z axes to show direction) indicate the number of nodes: radial and planar list a valid set of quantum numbers

a) 4s b) 3px c) 5dxz d) 3dx2-y2

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Quantum Numbers

6. Each of these sets of quantum numbers is invalid. Change one number in each to give a valid set of quantum numbers.

a) n = 1, l = 1, ml = –1, ms = –½

b) n = 1, l = 0, ml = +1, ms = +½

c) n = 5, l = 4, ml = +3, ms = +2

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Reactions with Water

7. Each of the following compounds is dissolved in and/or reacted with water. Will the resulting solution have a pH above or below 7? Draw the Lewis structure of the product which is acting as an acid or base.

a) magnesium oxide d) sodium carbonate

b) carbon dioxide e) lithium

c) nickel(II) nitrate f) fluorine

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Electron Configurations

8. Thallium (Tl) can adopt either of two non-zero oxidation states.

a) Write the electron configuration for neutral thallium using line notation.

b) Write the electron configuration for neutral thallium using line notation with the noble gas abbreviation.

c) What two non-zero oxidation states can thallium adopt? Justify your answer.

d) In which of these two non-zero oxidation states will thallium have a larger radius? Justify your answer.

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Bond Angles

9. As a general rule, the bond angles for simple hydrogen compounds and simple halogen compounds decrease as we go down a group.e.g. The bond angles for NH3, PH3, AsH3 and SbH3 are 106.8°, 93.5°, 92.0° and 91.5° respectively.Give a plausible explanation for this phenomenon.