Chemistry Revision V2

Which statement explains why ammonia gas, NH3, diffuses at a faster rate than

hydrogen chloride gas, HCl ?

• Ammonia expands to occupy all of the space available.

• Ammonia has a smaller relative molecular mass than hydrogen chloride.

• Ammonia is an alkali and hydrogen chloride is an acid.

• Ammonia molecules diffuse in all directions at the same time.

2.00 g of powdered calcium carbonate is added to 50.0 cm^3 of hydrochloric acid.

Which apparatus is used to measure the calcium carbonate and the hydrochloric acid?

• calcium carbonate: Balance | hydrochloric acid: burette

• calcium carbonate: Balance | hydrochloric acid: Thermometer

• calcium carbonate: Pipette | hydrochloric acid: burette

• calcium carbonate: pipette | hydrochloric acid: thermometer

The measurements from a chromatography experiment using substance F are shown. The

diagram is not drawn to scale. What is the Rf value of F?

• 0.55

• 0.61

• 0.90

• 1.64

Which statement about an atom of fluorine, F

, with atomic mass 19 and atomic number 9 is correct?

• It contains more protons than neutrons.

• It contains a total of 28 protons, neutrons and electrons.

• Its isotopes contain different numbers of protons.

• Its nucleus contains 9 neutrons.

Which row describes the formation of single covalent bonds in methane?

• A

• B

• C

• D

Which statement describes the structure of an ionic compound?

• It is a giant lattice of oppositely charged ions.

• It is a giant lattice of positive ions in a ‘sea’ of electrons.

• It is a giant molecule of oppositely charged ions.

• It is a simple molecule of oppositely charged ions.

Propane burns in oxygen.

C3H8 + xO2 → 3CO2 + yH2O

Which values of x and y balance the equation?

• x = 5 | y = 4

• x = 7 | y = 4

• x = 10 | y = 8

• x = 13 | y = 8

A tablet contains 0.080 g of ascorbic acid (Mr = 176).

What is the concentration of ascorbic acid when one tablet is dissolved in 200 cm3 of water?

• 9.1 x 10^-5 mol/dm^3

• 4.5 x 10^-4 mol/dm^3

• 9.1 x 10^-2 mol/dm^3

• 2.3 x 10^-3 mol/dm^3

Nitrogen reacts with hydrogen to produce ammonia.

N2 + 3H2 → 2NH3

The reaction is exothermic. The bond energies are shown in the table.

• –1473 kJ / mol

• –87 kJ / mol

• 87 kJ / mol

• 1473 kJ / mol

Which change in reaction conditions increases both the collision rate and the proportion of

molecules with sufficient energy to react?

• addition of a catalyst

• increasing the concentration of a reactant

• increasing the surface area of a reactant

• increasing the temperature of the reaction