L6 End of Year physical and inorganic

Which one of the following is a redox reaction?

• 2CrO₄^2- + 2H⁺ → Cr₂O₇^2- + H₂O

• 3Cl₂ + 6OH⁻ → 5Cl⁻ + ClO₃^- + 3H₂O

• HNO₃ + 2H₂SO₄ → NO + H₃O⁺ + 2HSO₄^-

• CaCO₃ + SiO₂ → CaSiO₃ + CO₂

Which atom has the greatest first ionisation energy?

• H

• He

• Li

• Ne

This question is about the reaction between propanone and an excess of ethane-1,2-diol, the equation for which is given above.

In a typical procedure, a mixture of 1.00 g of propanone, 5.00 g of ethane-1,2-diol and 0.100 g of benzenesulphonic acid, C₆H₅SO₃H, is heated under reflux in an inert solvent. Benzenesulphonic acid is a strong acid.

When the concentration of benzenesulphonic acid is doubled, the rate of the reaction doubles. It can be deduced that

• the reaction is first order overall

• the reaction is third order overall.

• the reaction is acid-catalysed.

• units for the rate constant, k, are mol⁻² dm⁶ s⁻¹.

Rate = k [A]² [B]

Correct units for the rate constant in the rate equation above are

• mol dm⁻³ s⁻¹

• mol⁻¹ dm⁻³ s⁻¹

• mol² dm⁻⁶ s⁻¹

• mol⁻² dm⁶ s⁻¹

Solutions of two compounds, W and X, react together in the presence of a soluble catalyst, Y, as shown in the equation

2W + X → Z

When the concentrations of W, X and Y are all doubled, the rate of reaction increases by a factor of four.

Which is a possible rate equation for this reaction?

• rate = k [W]² [X]

• rate = k [W]² [Y]

• rate = k [X] [Y]

• rate = k [X] [Z]

Refer to the unbalanced equation below when answering this question.

K₂Cr₂O7 + 3H₂C₂O₄ + _H₂SO₄ → Cr₂(SO₄)₃ + _H₂O + 6CO₂ + K₂SO₄

What is the reducing agent in this reaction?

• H⁺

• C₂O₄²⁻

• K⁺

• Cr₂O₇²⁻

Which substance is not produced in a redox reaction when solid sodium iodide reacts with concentrated sulfuric acid?

• H₂S

• HI

• SO₂

• I₂

Which species contains an element with an oxidation state of +4?

• NO₂⁺

• ClO₃⁻

• H₂SO₃

• PCl₅

Which species is not produced by a redox reaction between solid sodium iodide and concentrated sulfuric acid?

• Na₂SO₄

• H₂S

• S

• SO₂

Element Q forms a sulfate with formula QSO₄

Which of these could represent the electronic configuration of an atom of Q?

• [Ne]3s¹

• [Ne]3s²

• [Ne]3s²3p¹

• [Ne]3s¹3p²