Chemistry paper 1 H

How do you calculate the number of moles of a substance?

• mass (g) x relative mass

• relative mass + mass (g)

What takes place at the cathode?

• Reduction - the loss of electrons

• Reduction - the gain of electrons

• Oxidation - the loss of electrons

• Oxidation - the gain of electrons

In the electrolysis of molten sodium fluoride what ions are formed and which electrode do they migrate to?

• Only Na⁺ and F^- ions produced. Na⁺ migrates to the anode. F^- ions migrate to the cathode

• Only Na⁺ and F^- ions produced. Na⁺ migrates to the cathode. F^- ions migrate to the anode

• Na⁺, H⁺ OH^- and F^- ions produced. Positive ions migrate to the anode, negative to cathode

• Na⁺, H⁺ OH^- and F^- ions produced. Positive ions migrate to the cathode, negative to anode

What is the ionic equation for neutralisation?

• H^- + OH⁺ → H₂O

• 2H₂ + O₂ → 2H₂O

• H⁺ + OH^- → H₂O

• H⁺ + OH^- → H₂O⁺

In the electrolysis of copper chloride solution what ions are formed and which electrode do they migrate to?

• Cu²⁺, Cl^-, H⁺ and OH^- are formed. Cu²⁺ and H⁺ migrate to the anode, Cl^- and OH^- migrate to the cathode

• Only Cu²⁺ and Cl^-are formed. Cu²⁺ migrates to the anode, Cl^- migrates to the cathode

• Only Cu²⁺ and Cl^-are formed. Cu²⁺ migrates to the cathode, Cl^- migrates to the anode

• Cu²⁺, Cl^-, H⁺ and OH^- are formed. Cu²⁺ and H⁺ migrate to the cathode, Cl^- and OH^- migrate to the anode

Which half equation is correct for the reaction at the cathode during the electrolysis of lead bromide?

• 2Br^- + 2e → Br₂

• Pb²⁺ - 2e → Pb

• Pb²⁺ + 2e → Pb

• 2Br^- - 2e → Br₂

Calculate the number of sulfur dioxide molecules in 48.0 g, SO₂

(relative atomic masses: O = 16.0, S = 32.0; Avogadro constant = 6.02 × 10²³ mol^–1)

Give your answer in standard form and to three significant figures.

Use a star symbol for standard form e.g. 6.02 x 10*23

What are strong acids?

• Acids that completely dissociate into ions in solution. (Releasing H⁺ ions)

• Acids that partially dissociate into ions in solution. (Releasing H⁺ ions)

• Acids that completely dissociate into ions in solution. (Releasing OH^- ions)

• Acids that completely dissociate into ions in solution. (Releasing OH^- ions)

Which of the following statements are true for NaCl?

• It is an ionic compound, and the electrons are transferred forming ions.

• It is an covalent compound, and the electrons are shared forming ions.

• It has a high melting point as the electrostatic forces are strong requiring a lot of energy to overcome them.

• It can only conduct electricity when solid as the ions cannot flow.

CO₂ is a simple covalent compound, which of the following properties are true?

• CO₂ has a low melting point as the strong covalent bonds are broken.

• CO₂ has a low melting point as the weak intermolecular forces between molecules are broken.

• CO₂ can conduct electricity because there electrons that are free to move.

• CO₂ cannot conduct electricity because none of the electrons are free to move.