Which one of the equations below represents a reaction that is feasible at all temperatures?

• P(s) → Q(s) + R(g) endothermic

• 2L(g) + M(g) → 2N(g) exothermic

• S(g) → 2T(g) exothermic

• A(g) + B(g) → C(g) endothermic

Tags

NGSS.HS-PS1-4

The removal of silicon dioxide with limestone in the Blast Furnace can be represented by the following equation.

CaCO₃(s) + SiO₂(s) → CaSiO₃(l) + CO₂(g)

Which one of the following statements is not correct?

• There is an increase in entropy during this reaction.

• The calcium silicate formed floats on the surface of the molten iron.

• The calcium silicate formed can be used in the construction industry.

• Silicon dioxide is a basic oxide.

A 0.100 mol dm^–3 solution of X is found to have a pH of 2.50. The value of K_a in mol dm^–3 is

• 3.16 × 10^–2

• 3.16 × 10^–3

• 1.00 × 10^–4

• 1.00 × 10^–5

The following information concerns the gas-phase reaction of nitrogen monoxide with hydrogen.

2NO(g) + 2H₂(g) ⇌ N₂(g) + 2H₂O(g)

A series of experiments was carried out in a reaction vessel at constant temperature. The initial rate of reaction increased by a factor of 2 when the initial pressure of NO was doubled and that of H₂ was halved. When both pressures were halved, the initial rate decreased by a factor of 8.

Which of the following are correct statements.

1 the overall order of reaction is 2.

2 the reaction is first order with respect to hydrogen.

3 the reaction is first order with respect to nitrogen monoxide.

4 the overall order of reaction is 3.

• 1, 2 and 3 only correct

• 1 and 3 only correct

• 2 and 4 only correct

• 4 only correct

Tags

NGSS.HS-PS1-5

Which of the following are Lewis bases:

1 H₂O

2 NH₄⁺

3 Cl^–

4 C₂H₆

• 1, 2 and 3 only correct

• 1, 2 and 3 only correct

• 2 and 4 only correct

• 4 only correct

Which of the following are correct:

1 1.713 g of barium hydroxide is neutralised exactly by 100 cm³ of 0.100 mol dm^–3 sulphuric acid.

2 in sulphuric acid, the oxidation state of sulphur is +6.

3 the pH of 0.0200 mol dm^–3 sulphuric acid is 1.70.

• 1, 2 and 3 only correct

• 1 and 2 only correct

• 2 and 3 only correct

• 1 only correct

Tags

NGSS.HS-PS1-1

NGSS.HS-PS1-2

What is the value of ∆H (in kJ mol⁻¹ ) for the reaction below?

• 124

• 101

• -101

• -124

Tags

NGSS.HS-PS1-4

When ∆G^θ for a reaction is negative, the reaction is

• fast

• endothermic

• reversible

• spontaneous

For a gaseous reaction, the equilibrium constant expression is shown in the image.

Which equation corresponds to this equilibrium expression?

• 4NH₃ + 5O₂ ⇌ 4NO + 6H₂O

• 4NO + 6H₂O ⇌ 4NH₃ + 5O₂

• 8NH₃ + 10O₂ ⇌ 8NO + 12H₂O

• 2NO + 3H₂O ⇌ 2NH₃ +5/2O₂

The standard electrode potentials for Al and Mn are given below:

Al³⁺(aq) + 3e⁻ ⇌ Al(s) E^θ(V) = −1.66 V

Mn²⁺(aq) + 2e⁻ ⇌ Mn(s) E^θ(V) = −1.18 V

What is the potential of a cell prepared with these metals in contact with 1.0 mol dm⁻³ solutions of their ions?

• 0.22 V

• 0.48 V

• 2.84 V

• 3.43 V

Tags

NGSS.HS-PS1-1

NGSS.HS-PS1-2