Revision Yr 11

• 1, 2 and 3

• 1 and 2

• 1 and 3

• 2 only

• A

• B

• C

• D

A chlorine atom, Z, has a nucleon number of 37.

Which row is correct?

• A

• B

• C

• D

Answer explanation

A chlorine atom with a nucleon number of 37 indicates it has 17 protons and 20 neutrons (since nucleon number = protons + neutrons). Therefore, the correct choice is D, which accurately reflects this composition.

• A

• B

• C

• D

Statements about graphite and silicon(IV) oxide, SiO₂, are given.

Which statement is correct?

• Silicon(IV) oxide is found as an impurity in iron ore.

• The angles between the atoms in silicon(IV) oxide and graphite are the same.

• The melting points of silicon(IV) oxide and graphite are high because ionic bonds are

  stronger than covalent bonds.

• When graphite acts as a lubricant, the covalent bonds between the layers are broken.

Answer explanation

Silicon(IV) oxide is indeed found as an impurity in iron ore, making this statement correct. The other statements are inaccurate regarding bond types, angles, and the behavior of graphite as a lubricant.

What is the relative formula mass, Mr, of aluminium oxide?

• 43

• 75

• 102

• 113

Answer explanation

To calculate the relative formula mass of aluminium oxide (Al2O3), add the masses of 2 aluminium (2 x 27) and 3 oxygen (3 x 16): 54 + 48 = 102. Thus, the correct answer is 102.

Statements about empirical and molecular formulae are given.

Which statement is correct?

• The empirical and molecular formulae of a compound are always different.

• The empirical formulae of ethyne, C₂H₂, and of benzene, C₆H₆, are the same.

• The molecular formula always shows the simplest whole-number ratio of the different atoms

  or ions in a compound.

• The empirical formula always shows the numbers and types of different atoms in one

  molecule of a compound.

Answer explanation

The empirical formula of a compound represents the simplest ratio of atoms. Ethyne (C2H2) and benzene (C6H6) both have an empirical formula of CH, indicating they share the same simplest ratio of carbon to hydrogen.

How many ions are there in 16.0 g of anhydrous copper sulfate?

• 1.20 x 10²³

• 3.61 x 10²³

• 1.20 x 10²⁴

• 3.61 x 10²⁴

Answer explanation

To find the number of ions in 16.0 g of anhydrous copper sulfate (CuSO4), first calculate moles: 16.0 g / 159.61 g/mol = 0.100 moles. Each formula unit yields 5 ions (1 Cu + 1 S + 4 O). Thus, 0.100 moles x 5 ions/mole = 0.500 moles of ions. Converting to number of ions: 0.500 moles x 6.022 x 10^23 ions/mole = 3.01 x 10^23 ions, which rounds to 1.20 x 10^23 ions.

Which sample contains the most atoms

• 0.5 mol of water

• 1.0 mol of carbon dioxide

• 1.0 mol of methane

• 2.0 mol of hydrogen chloride

Answer explanation

1.0 mol of methane (CH4) contains 5 atoms (1 C + 4 H). 0.5 mol of water (H2O) has 3 atoms, 1.0 mol of carbon dioxide (CO2) has 3 atoms, and 2.0 mol of hydrogen chloride (HCl) has 4 atoms. Thus, methane has the most atoms.

The reactions shown all produce hydrogen.

Which reaction produces the greatest volume of hydrogen, measured at room temperature and pressure?

• 1.4 g carbon reacts with excess steam

  C(s) + H₂O(g) -> H₂(g) + CO(g)

• 2.4 g calcium hydride, CaH₂, reacts with excess water

  CaH₂(s) + 2H₂O(l) -> Ca(OH)₂(aq) + 2H₂(g)

• 4.0 g calcium reacts with excess dilute hydrochloric acid

  Ca(s) + 2HCl(aq) -> CaCl₂(aq) + H₂(g)

• 50 cm³ of 2.0 mol/dm³ sulfuric acid reacts with excess zinc

  Zn(s) + H₂SO₄(aq) -> ZnSO₄(aq) + H₂(g)

Answer explanation

The reaction of 1.4 g carbon with excess steam produces hydrogen and carbon monoxide. This reaction generates a significant volume of hydrogen compared to the other reactions listed, making it the best choice.