Most Missed Questions June 2009 1 State in

Most Missed Questions June 2009

1 • State, in terms of intermolecular forces, why the boiling point of propane at 1 atmosphere is lower than the boiling point of butane at 1 atmosphere. [1]

2 • Which element is composed of molecules that each contain a multiple covalent bond? • 1 chlorine • 2 fluorine • 3 hydrogen • 4 nitrogen

3. • A beta particle may be spontaneously emitted from • 1 a ground-state electron • 2 a stable nucleus • 3 an excited electron • 4 an unstable nucleus

4 • Given the balanced equation below representing a reaction: • Decreasing the concentration of Na 2 S 2 O 3(aq) decreases the rate of reaction because the • • 1 activation energy decreases • 2 activation energy increases • 3 frequency of effective collisions decreases • 4 frequency of effective collisions increases

5 • Given the equation below representing a reaction at equilibrium: • • • Which change favors the reverse reaction? 1 decreasing the concentration of HI(g) 2 decreasing the temperature 3 increasing the concentration of I 2(g) 4 increasing the pressure

6. • Which reaction occurs spontaneously? 1. 2. 3. 4.

7. • Which formula represents a nonpolar molecule? • 1 CH 4 • 2 HCl • 3 H 2 O • 4 NH 3

8 • Which sample of HCl(aq) contains the greatest number of moles of solute particles? • 1 1. 0 L of 2. 0 M HCl(aq) • 2 2. 0 L of 2. 0 M HCl(aq) • 3 3. 0 L of 0. 50 M HCl(aq) • 4 4. 0 L of 0. 50 M HCl(aq)

9. • Which change in p. H represents a hundredfold increase in the concentration of hydronium ions in a solution? • 1 p. H 1 to p. H 2 • 2 p. H 1 to p. H 3 • 3 p. H 2 to p. H 1 • 4 p. H 3 to p. H 1

• Which nuclide is used to investigate human thyroid gland disorders? • 1 carbon-14 • 2 potassium-37 • 3 cobalt-60 • 4 iodine-131

Answers 1. 2. 4 3. 4 4. 3 5. 2 6. 1 7. 1 8. 2. 9. 4 10. 4