Category: Chemistry

The indicator thymol blue changes from yellow to blue of the pH range 8.0 to 9.6. The indicator could be used to detect accurately the end-point in a titration of roughly 0.1 mol dm^-3 solutions of:

(i) ethanoic acid with sodium hydroxide

(ii) hydrochloric acid with ammonia

(iii) hydrochloric acid with sodium hydroxide

(iv) ethanoic acid with ammonia

Which of these compounds give an alkaline solution when mixed with water?

(i) NH₄Cl

(ii) NH₃

(iii) CH₃CH₂OH

(iv) CH₃CO₂Na

Which of these are examples of acid-base reactions according to the Bronsted-Lowry theory.

(i) ZnO_(s)+2H₃O⁺_(aq)->Zn²⁺_(aq)+3H₂O_(l)

(ii) H₂O_(l)+H₂O_(l)->H₃O⁺ _(aq)+ OH^-_(aq)

(iii) NH_3(g)+HBr_(g)->NH₄Br _(s)

(iv) SO_2(g)+H₂O_(l)->H₂SO_3(aq)

pH = 2.9 for a solution which contains equal concentrations of chlorethanoic acid and sodium chlorethanoate. What is the pH of the solution after mixing it with twice its own volume of pure water?

The value of K_a for ethanoic acid = 1.7 x 10^-5 mol dm^-3 (pK_a = 4.8). During a titration of 20.0cm³ 0.1 mol dm^-3 solution of ethanoic acid with 0.1 mol dm^-3 sodium hydroxide, what is the pH of the mixture in the flask after adding 10.0 cm³ of the alkali?

What is the pH of a 0.01 mol dm^-3 solution of methanoic acid given that for this acid: K_a = 1.6 x 10^-4 mol dm^-3 at 298K ?

Why does the term [H₂O_(l)]not appear in the expression for K_a for methanoic acid?

What is the pH of a 0.01 mol dm^-3 solution of sodium hydroxide given that Kw = 1.0 x 10^-14 mol²dm^-6 at 298K?

What is the hydrogen ion concentration in an aqueous solution if the pH = 3.0?

What is the conjugate acid of HSO₄^-?

Consider the following equilibrium:

2SO_2(g) + O_2(g) <=>2SO_3(g)

8.00 mol of SO₂ was mixed with 5.00 mol of O₂ and the mixture sealed in a heated vessel of volume of 1.00 dm³. The mixture was left until no further observable change in composition took place. At this point, 2.00 mol of O₂ was present in the mixture and the pressure was recorded as 200 kPa.

Calculate the value K_c (in units: mol^-1 dm³) under these conditions.

Consider the following equilibrium:

2SO_2(g) + O_2(g) <=>2SO_3(g)

8.00 mol of SO₂ was mixed with 5.00 mol of O₂ and the mixture sealed in a heated vessel of volume of 1.00 dm³. The mixture was left until no further observable change in composition took place. The pressure was recorded as 200 kPa. At this point, 2.00 mol of O₂ was present in the mixture.

Calculate the value of K_p (in units: kPa^-1) under these conditions.

Consider the following equilibrium for the Haber-Bosch process:

3H_2(g) + N_2(g) <=>2NH_3(g)

32.0 mol of H₂ was combined with 12.0 mol of N₂ and the mixture sealed and pressurised in a vessel of volume 2.00 dm³. The mixture was left until no further observable change in composition took place. At this point, 4.00 mol of NH₃ was found to be present in the mixture. The pressure was recorded as 200 000 kPa.

Calculate the value of K_c (in units: mol^-2 dm⁶) under these conditions.

Consider the following equilibrium for the Haber-Bosch process:

3H_2(g) + N_2(g) <=>2NH_3(g)

32.0 mol of H₂ was combined with 12.0 mol of N₂ and the mixture sealed and pressurised in a vessel of volume 2.00 dm³. The mixture was left until no further observable change in composition took place. At this point, 4.00 mol of NH₃ was found to be present in the mixture The pressure was recorded as 200 000 kPa.

Calculate the value of K_p (in units: kPa^-2) under these conditions.

Consider the following equilibrium:

N_2(g) + O_2(g) <=>2NO_(g)

5.00 x 10^-3 mol of N₂ was mixed with 4.00 x 10^-3 mol of O₂ and 11.0 x 10^-3 mol of NO and the mixture sealed in a container. The volume of the container was 0.500 dm³. The mixture was left to form a stable equilibrium. At this point, 9.00 x 10^-3 mol of NO was present in the mixture. The pressure was recorded as 45000 kpa

Calculate the value of K_c (no units) under these conditions.

Consider the following equilibrium:

N_2(g) + O_2(g) <=>2NO_(g)

5.00 x 10^-3 mol of N₂ was mixed with 4.00 x 10^-3 mol of O₂ and 11.0 x 10^-3 mol of NO and the mixture sealed in a container. The volume of the container was 0.500 dm³. The mixture was left to form a stable equilibrium. At this point, 9.00 x 10^-3 mol of NO was present in the mixture. The pressure was recorded as 45000 kpa

Calculate the value of K_p (no units) under these conditions.

Consider the following equilibrium:

3Fe_(s) + 4H₂O_(g) <=>Fe₃O_4(s)+ 4H_2(g)

40.0 g of iron wool was placed in a vessel of volume 2.00 dm³. The iron was exposed to 20.0 mol of high pressure steam and the system allowed to settle to equilibrium. At equilibrium, 0.250 mol of hydrogen was found in the vessel. The gauge on the pressure vessel read 1 000 kPa. The volume of iron wool was insignificant.

Calculate the value of K_c (no units) under these conditions.

Consider the following equilibrium:

3Fe_(s) + 4H₂O_(g) Fe₃O_4(s)+ 4H_2(g)

40.0 g of iron wool was placed in a vessel of volume 2.00 dm³. The iron was exposed to 20.0 mol of high pressure steam and the system allowed to settle to equilibrium. At equilibrium, 0.250 mol of hydrogen was found in the vessel. The gauge on the pressure vessel read 1 000 kPa. The volume of iron wool was insignificant.

Calculate the value of K_p (no units) under these conditions.

Consider the following equilibrium for the reaction that generates hydrogen for use in the Haber-Bosch Process:

CH_4(g) + H₂O_(g) CO_(g) + 3H_2(g)

100 mol of CH₄ was mixed with 100 mol of H₂O and 200 mol of H₂.The mixture was given time to reach equilibrium. At this point, 350 mol of H₂ was present in the mixture. The pressure inside the 1.20 m³ vessel was measured as 400 kPa

Calculate the value of K_c (in units: mol² dm^-6) under these conditions.

Consider the following equilibrium for the reaction that generates hydrogen for use in the Haber-Bosch Process:

CH_4(g) + H₂O_(g) <=>CO_(g) + 3H_2(g)

100 mol of CH₄ was mixed with 100 mol of H₂O and 200 mol of H₂.The mixture was given time to reach equilibrium. At this point, 350 mol of H₂ was present in the mixture. The pressure inside the 1.20 m³ vessel was measured as 400 kPa

Calculate the value of K_p (in units: kPa²) under these conditions.

Consider the values of the equilibrium constant for this reversible reaction:

H_2(g) +I_2(g) <=> 2HI_(g)

Temperature: 500K, value of K_c = 160

Temperature: 1000K, value of K_c = 54.

This information shows that:

(i) HI decomposes rapidly at 500 K

(ii) Raising the temperature causes the equilibrium to shift to the left

(iii) Raising the pressure causes the equilibrium to shift to the right

(iv) The reaction is exothermic

For which of the following equilibria, does raising the pressure favours the formation of products?

(i) H_2(g) + C_(s) <=> H_2(g) + CO_(g)

(ii) 4NH_3(g) + 5O_2(g) <=> 4NO_(g) + 6H₂O_(g)

(iii) 2HCl_(g) + I_2(g) <=> 2HI_(g) + Cl_2(g)

(iv) 2SO_2(g) + O_2(g) <=> 2SO_3(g)

These reactions are rapid at 298 K. Which of the reactions goes effectively to completion?

(i) I^-_(aq) + I_2(aq) <=> I₃^-_(aq) K_c = 7.1 x 10^-2 mol^-1 dm³

(ii) Cu²⁺_(aq) + 4NH_3(aq) <=> [Cu(NH₃)₄]²⁺_(aq) K_c = 1.4 x 10¹³ mol^-4dm¹²

(iii) 2H₂O_(l) <=> H₃O⁺_(aq) + OH^-_(aq) K_c = 1.0 x 10^-14 mol² dm^-6

(iv) Cu²⁺_(aq) + Zn_(s) <=> Cu_(s) + Zn²⁺_(aq) K_c = 1 x 10³⁷

At a given temperature, which of these expressions have a constant value for all equilibrium mixtures of hydrogen, iodine vapour and hydrogen iodide?

(i) [H₂]/[I₂],

(ii) [HI]²/[H₂][I₂],

(iii) [I₂]/[H₂]

(iv) [H₂][I₂]/[HI]²

Which of the following are examples of heterogeneous equilibria?

(i) CaCO_3(s) <=> CaO_(s) + CO_2(g)

(ii) 2CrO₄^2-_(aq) + 2H⁺_(aq) <=> Cr₂O₇^2-_(aq) + H₂O_(l)

(iii) Ag⁺_(aq) + Fe²⁺_(aq) <=> Ag_(s) + Fe³⁺_(s)

(iv) Co²⁺_(aq) + 6NH_3(aq) <=> [Co(NH₃)₆]²⁺_(aq)

K_p = 4 atm for the dissociation of N₂O₄ at 350 K when the equilibrium is described by this equation.

N₂O_4(g) <=> 2NO_2(g)

What is the value of K_p for this equilibrium:

2NO_2(g) <=> N₂O_4(g)?

For the following equilibrium K_c = 25.0 mol^-2 dm⁶ at a particular temperature.

CO_(g) + 2H_2(g) <=> CH₃OH_(g)

Which of these changes of conditions alter the value of K_c?

(i)Raising the concentration of hydrogen

(ii)Adding a catalyst

(iii)Raising the pressure

(iv)Lowering the temperature

For the equilibrium: CaCO_3(s) <=> CaO_(s) + CO_2(g)

If pressures are measured in pascals (Pa) what are the units of K_p for this equilibrium:

2H_2(g) + O_2(g) <=> 2H₂O_(g)

A mixture of 1 mol ethanoic acid and 1 mol ethanol was allowed to reach equilibrium at a constant temperature. Analysis of the equilibrium mixture showed that it contained ¹/₃ mol ethanoic acid and ¹/₃ mol ethanol:

CH₃CO₂H_(l) + C₂H₅OH_(l) <=> CH₃CO₂C₂H_5(l) + H₂O_(l)

What is the value of K_c?

Consider the synthesis of methanol in the following equilibrium:

CO_(g) + 2H_2(g) <=>CH₃OH_(g)

2.00 mol of CO was mixed with 4.00 mol of H₂ and the mixture sealed in a container. The mixture was left until no further observable change in composition took place. At this point, 1.90 mol of CH₃OH was present in the mixture.

Calculate the value of the mole fraction of CH₃OH present in the mixture under these conditions.

Consider the following equilibrium:

N_2(g) + O_2(g) <=>2NO_(g)

1.80 x 10^-3 mol of N₂ was mixed with 2.40 x 10^-3 mol of O₂ and 7.20 x 10^-3 mol of NO and the mixture sealed in a container. The mixture was left until no further observable change in composition took place. At this point, 4.80 x 10^-3 mol of O₂ was present in the mixture.

Calculate the value of the mole fraction of O₂ present in the mixture under these conditions.

Consider the following equilibrium for the reaction that generates hydrogen for use in the Haber-Bosch Process:

CH_4(g) + H₂O_(g) <=>CO_(g) + 3H_2(g)

140 mol of CH₄ was mixed with 100 mol of H₂O and the mixture given time to reach equilibrium. At this point, 240 mol of H₂ was present in the mixture.

Calculate the value of the mole fraction of CH₄ present in the mixture under these conditions.

Consider the following equilibrium for the Haber-Bosch process:

3H_2(g) + N_2(g) <=>2NH_3(g)

6.00 mol of H₂ was combined with 6.00 mol of N₂ and the mixture sealed in a heated and pressurised vessel with an iron catalyst. The mixture was left until no further observable change in composition took place. At this point, 3.00 mol of NH₃ was found to be present in the mixture.

Calculate the value of the mole fraction of NH₃ present in the mixture under these conditions.

Consider the following equilibrium:

2SO_2(g) + O_2(g) <=>2SO_3(g)

35.0 mol of 2SO₂ was mixed with 22.5 mol of O₂ and the mixture sealed in a heated vessel with vanadium (V) oxide catalyst. The mixture was left until no further observable change in composition took place. At this point, 15.0 mol of O₂ was present in the mixture.

Calculate the value of the mole fraction of SO₃ present in the mixture under these conditions

Consider the following homogenius gaseous equilibrium:

ethene + steam <=> ethanol

0.180 mol of ethene as mixed with 1.03 mol of steam and the the mixture heated in the presence of a catalyst. The mixture was sealed in a vessel and allowed to reach equilibrium. At equilibrium, 0.110 mol of ethanol was present in the equilibrium mixture.

Calculate the value of the mole fraction of ethanol present in the mixture under these conditions.

Consider the following equilibrium:

H_2(g) + I_2(g)<=>2HI_(g)

1.50 mol of HI was placed in a sealed vessel and allowed to decompose. At equilibrium, 0.500 mol of HI remained in the vessel

Calculate the value of the mole fraction of HI present in the mixture under these conditions.

Consider the following equilibrium:

PCl_3(g) + Cl_2(g) <=> PCl_5(g)

6.00 mol of PCl₃was mixed with 6.00 mol of Cl₂ and the mixture sealed in a vessel and allowed to reach equilibrium. At equilibrium, 2.00 mol of PCl₅ was present in the equilibrium mixture.

Calculate the value of the mole fraction of PCl₅ present in the mixture under these conditions.

Consider the following reaction:

3NO_(g) => 2N₂O_(g) + NO_2(g)

The rate equation was found, by experiment:

rate = k [NO]²

Which of the following statements is/are true?

(i) There are two particles of the radical NO involved in the rate determining step

(ii) One particle of NO must be used up in a step that isn’t the rate determining step

(iii) Quadrupling [NO] raises the rate of nitrogen dioxide by, 2N₂O₂ production by 16 times

(iv) Tripling [NO] raises the rate of nitrous oxide, 2N₂O production by 8 times

Consider the following reaction:

2ICl_(g) + H_2(g) => HCl _(g)+ I_2(g)

The rate equation was found, by experiment:

rate = k [ICl] [H₂]

Which of the following statements is/are true?

(i) There are two particles involved in the rate determining step

(ii) There are two IClparticles involved in the rate determining step

(iii) IClparticles must be involved in involved in more than one step

(iv) The rate of production of I_2(g) doubles when both [ICl] and [H] double

Consider the following reaction:

2N₂O_5(g) => 4NO_2(g)+ O_2(g)

The rate equation was found, by experiment:

rate = k [N₂O₅]

Which of the following statements is/are true?

(i) Doubling the concentration N₂O₅ caused the rate of production of 4NO₂ to increase by 4 times

(ii) Tripling the concentration N₂O₅ caused the rate of production of O₂ to increase by 3 times

(iii) There are two particles of N₂O₅ involved in the rate determining step

(iv) The mechanism is probably multi step

Consider the following reaction:

C₄H₉Cl_(aq) + OH^-_(aq) => C₄H₉OH_(aq) + Cl^-_(aq)

The rate equation was found, by experiment:

rate = k [C₄H₉Cl]

Which of the following statements is/are true?

(i) Increasing the concentrations of all reactants speeds up the nucleophilic substitution reaction

(ii) The mechanism probably has only one step

(iii) There are two particles involved in the rate determining step

(iv) OH^- is required for the overall reaction to proceed

Consider the following reaction.

O_3(g) + Cl_(g) => O_2(g)+ ClO_(g)

The rate equation was found, by experiment.

rate = k [O₃] [Cl]

Which of the following statements is/are true?

(i) Doubling [O₃] has no effect on the rate of the reaction

(ii) The mechanism probably has more than one step

(iii) There is one particle involved in the slowest step

(iv) The mechanism probably has only one step

Consider the following reaction:

2H₂O_2(g) => 2H₂O_(g)+ O_2(g)

The rate equation was found, by experiment:

rate = k [H₂O₂]

Which of the following statements is/are true?

(i) The mechanism must be multi step

(ii) Doubling [H₂O_{] quadruples the rate of the reaction}

(iii) [H₂O] must be consumed in more than one step

(iv) The mechanism probably has only one step

Consider the following reaction:

2NO_(g) + O_2(g) => 2NO_2(g)

The rate equation was found, by experiment:

rate = k [NO_(g)]² [O_2(g)]

Which of the following statements is/are true?

(i) Doubling [O₂] has no effect on the rate of the reaction

(ii) Doubling both [NO] and [O₂] quadruples the rate of the reaction

(iii) Tripling [NO] triple the rate of the reaction

(iv) The mechanism may have only one step

Consider the following reaction:

2NO_(g) + 2H_2(g) => N_2(g) + 2H₂O_(g)

The rate equation was found, by experiment:

rate = k [NO]²[H₂]

Which of the following statements is/are true?

(i) The mechanism has more than one step

(ii) Doubling [NO₂] quadruples the rate of the reaction

(iii) H₂ is consumed in more than one of the steps

(iv)The mechanism has only one step

Consider the following reaction:

2NO_2(g) + F_2(g) => 2NO₂F_(g)

The rate equation was found, by experiment:

rate = k [NO₂] [F₂]

Which of the following statements is/are true?

(i) The mechanism has more than one step

(ii) Doubling [NO₂] doubles the rate of the reaction

(iii) NO₂ is produced in one of the steps

(iv) The mechanism has only one step

Consider the following reaction:

NO_2(g) + CO_(g) => NO_(g)+ CO_2(g)

The rate equation was found, by experiment:

rate = k [NO₂]²

Which of the following statements is/are true?

(i) The mechanism has more than one step

(ii) CO is involved in the rate determining step

(iii) NO₂ is produced in one of the steps

(iv) The mechanism has only one step

Which graph represents the disappearance of a reactant that displays first order kinetics?

What value should go in the blank box in the table?

What are the units of k for this reaction?

What is the value of the rate constant, k for this reaction at this temperature?

By inspection of this experimental data, what is the rate equation for this reaction?

What value should go in the blank box in the table?

What are the units of k for this reaction?

What is the value of the rate constant, k for this reaction at this temperature?

By inspection of this experimental data, what is the rate equation for this reaction?

What are the units of k for this reaction?

What is the value of the rate constant, k for this reaction at this temperature?

By inspection of this experimental data, what is the rate equation for this reaction?

What are the units of k for this reaction?

[1] s^-1

[2] mol^-1 dm³ s^-1

[3] mol^-2 dm⁶ s^-1

[4] mol^-3 dm⁹ s^-1

What is the value of the rate constant, k for this reaction at this temperature?

By inspection of this experimental data, what is the rate equation for this reaction?

What are the units of k for this reaction?

What is the value of the rate constant, k for this reaction at this temperature?

By inspection of this experimental data, what is the rate equation for this reaction?

The graph from an experiment to study the decomposition of hydrogen peroxide shows how the concentration of the hydrogen peroxide varied with time at constant temperature.

Time = 0 minutes, [H₂O₂] = 0.020 mol dm^-3

Time = 654 minutes, [H₂O₂] = 0.010 mol dm^-3

Time = 1308 minutes, [H₂O₂] = 0.005 mol dm^-3

This suggests that, under the conditions of the experiment:

(i) the reaction is zero order with respect to hydrogen peroxide

(ii) the concentration after 1962 minutes was 0.0025 mol dm^-3

(iii) the rate of reaction was constant for the first 654 seconds

(iv) the half-life of the reaction was 654 minutes

The activation energy for the reaction

A + B -> C + D is 38 kJ mol^-1

The activation energy for the reaction

C + D -> A + B is 65 kJ mol^-1

There is a catalyst which lowers the activation energy for the reaction of A with B by 10 kJ mol^-1.

This shows that:

(i) the reaction of A with B is exothermic

(ii) the enthalpy change for the reaction of C with D is +27 kJ mol^-1

(iii) in the presence of the catalyst the activation energy for the reaction of C with D is 55 kJ mol^-1

(iv) the reaction of A with B is overall second order.

The reaction of hydrogen gas with nitrogen monoxide gas is first order with respect to H_2(g) and second order with respect to NO_(g). It follows that:

(i) rate = k[H_2(g)][NO_(g)]²

(ii) doubling the concentration of NO_(g) increases the rate by a factor of 4

(iii) the overall order of reaction is 3

(iv) halving the concentration of hydrogen reduces the rate by a factor of 1.

The activation energy for the reaction of cobalt metal with aqueous S₂O₈^2- ions is close to 50 kJ mol^-1. The rate of reaction for the metal when a cylinder of cobalt metal rotates rapidly in a solution of aqueous S₂O₈^2- ions at 15^oC is 1.80 mg min^-1. This suggests that at 25^oC the rate of reaction would be about:

The reaction of bromine with propanone in acid solution is zero order with respect to bromine, first order with respect to propanone and first order with respect to hydrogen ions.

At a given temperature, the rate of disappearance of bromine is 1.20 x 10^-4 mol dm^-3 when

[CH₃COCH₃] = 0.30 mol dm^-3

[Br₂] = 0.05 mol dm^-3

[H+] = 0.10 mol dm^-3

What is the rate of disappearance bromine when

[CH₃COCH₃] = 0.10 mol dm^-3

[Br₂] = 0.10 mol dm^-3 and [H+] = 0.05 mol dm^-3?

The rate equation for the decomposition of gaseous ethanal takes the form:

rate =k[CH₃CHO]²

The rate of reaction = 0.080 mol dm^-3 s^-1 when the concentration of ethanal = 0.20 mol dm^-3.

The value of the rate constant is:

The decomposition of dinitrogen pentoxide gas into nitrogen and oxygen is first order with respect to N₂O₅. The units of the rate constant are:

Nitrogen monoxide gas reacts with oxygen gas to form nitrogen dioxide gas. If the rate of formation of nitrogen dioxide is 1.4 x 10^-5 mol dm^-3, what is the rate of disappearance of oxygen?

Which technique would you use to measure the rate of reaction for the hydrolysis of ethyl ethanoate?

What does the symbol [X] represent?

Which of these are examples of kinetic stability?

(i) A solution of hydrogen peroxide can be stored at room temperature

(ii) Hydrogen does not ignite in air at room temperature

(iii) Aluminium does not corrode in moist air

(iv) Magnesium oxide does not decompose on heating

An alloy of platinum with rhodium is the catalyst used:

(i) in catalytic converters to cut pollution from motor vehicles

(ii) in the synthesis of ammonia from nitrogen and hydrogen

(iii) in the oxidation of ammonia to NO_(g) during the manufacture of nitric acid

(iv) in the hydrogenation of vegetable oils.

Which of these statements about catalysts are true?

(i) A catalyst speeds up a forward reaction but slows down the reverse reaction

(ii) With a catalyst the enthalpy change for the reaction becomes more negative

(iii) With a catalyst the pathway for the reverse reaction has a higher activation energy

(iv) With a catalyst the pathway for the forward reaction has a lower activation energy

A Maxwell-Boltzman plot shows the distribution of molecular energies in a sample of gas at a 300K. The curve showing the distribution at 310K:

(i) has a wider spread,

(ii) has a higher peak,

(iii) has the peak shifted to the right,

(iv) has a larger area under the curve.

For which of these reactions can the rate of reaction be studied by collecting one of the products over water in a graduated tube (or measuring cylinder) inverted in a trough of water?

(i) Na₂SO_3(s) + 2HCl_(aq) -> 2NaCl_(aq) + SO_2(g) + H₂O_(l)

(ii) Zn_(s) + H₂SO_4(aq) -> H_2(g) + ZnSO_4(aq)

(iii) 2KCl_(s) + H₂SO_4(l) -> KHSO_4(s) + HCl_(g)

(iv) CaCO_3(s) + 2HNO_3(aq) -> Ca(NO₃)_2(aq) + CO_2(g) + H₂O_(l)

The activation energy for the reaction of sodium thiosulfate with acid is close to 50 kJ mol^-1. Mixing a measured volumes of sodium thiosulfate solution and hydrochloric acid at 30^oC produces a certain amount of sulfur in 120 seconds.

Repeating the experiment with all the conditions the same except the temperature is 40 ^oC produces the same amount of sulfur in:

When 0.08 g magnesium ribbon reacts with 50 cm³ of 2.00 mol dm^-3 hydrochloric acid the reaction produces 80 cm³ gas in 400 seconds at room temperature and pressure but then stops. On repeating the reaction under the same conditions with 0.08 g magnesium ribbon and 100 cm³ of 1.00 mol dm^-3 hydrochloric acid the outcome is that the reaction:

When a sample of calcium carbonate reacts with dilute hydrochloric acid, 144 cm³ of carbon dioxide form in 20 seconds at room temperature and pressure.

What is the rate of loss of hydrochloric acid in moles per second. (Volume of 1 mol gas under these conditions = 24 000 cm³)

Thiosulfate ions react with acid to produce a precipitate of sulfur. The following volumes of sodium thiosulfate solutions are mixed in separate small flasks with 10 cm³ samples of 2.0 mol dm^-3 hydrochloric acid together with enough water to make the total volume 50 cm³.

In which flask does the precipitate of sulfur form fastest?

The activation energy for the reaction of H_2(g) with I_2(g) is 120 kJ mol^-1. The standard enthalpy change for the reaction is +53 kJ mol^-1.

What is the activation energy for the decomposition of hydrogen iodide into its elements?

This is the ¹H NMR spectrum of:

This is the ¹H NMR spectrum of:

This is the ¹H NMR spectrum of:

This is the ¹H NMR spectrum of:

This is the ¹H NMR spectrum of:

This is the ¹H NMR spectrum of:

This is the ¹H NMR spectrum of:

This is the ¹³C NMR spectrum of:

How many peaks would you expect to see in the ¹³C spectrym of 3-propyl aminobenzene?

How many peaks would you expect to see in the ¹³C spectrym of 2,5-dimethyltetrahydrofuran?

Which of these statements is true of a solution of a racemic mixture?

(i) It contains asymmetric molecules,

(ii) It is a mixture of enantiomers,

(iii) It contains equal amounts of optical isomers,

(iv) It rotates the plane of polarised light

Which of these compounds can exist in two enantiomeric forms?

(i) 2-methylbutan-1-ol,

(ii) 2-bromo-1-chlorobutane,

(iii) 2-chloropentane,

(iv) 1-chlorobutane

Which of these compounds are chiral?

(i) propan-1-ol,

(ii) propan-2-ol,

(iii) butan-1-ol,

(iv) butan-2-ol

Which of these compounds are chiral?

(i) CH₂Cl₂

(ii) CH₂ClBr

(iii)CHCl₂F

(iv) CH₃CHClBr

Which of these molecules are polar?

(i) trans but-2-ene,

(ii) trans 1,2-dichloroethene,

(iii) cis but-2-ene,

(iv) cis 1,2-dichloroethene

The two compounds formed on heating 3-bromo-2-methylpentane with KOH in ethanol (which causes elimination!) are:

(i) alkenes,

(ii) position isomers,

(iii) hydrocarbons,

(iv) E/Z isomers

Which of these compounds have E/Z isomers?

(i) pent-2-ene,

(ii) 2-methylpent-2-ene,

(iii) 1,2-dichloropropene,

(iv) hex-1-ene

Which of these types of isomerism are examples of stereoisomerism.

(i) chain isomerism

(ii) E/Zisomerism

(iii) functional group isomerism

(iv) optical isomersim

Which of these compounds are functional group isomers of

HCO₂CH₂CH₂CH₃?

(i) ethyl ethanoate,

(ii) 2-methylpropanoic acid,

(iii) methyl propanoate,

(iv) butanoic acid

Which of these compounds are chain isomers of 2-methylpentane

(i) hexane,

(ii) 2,2-dimethylpentane,

(iii) 2,3-dimethylbutane,

(iv) 2,2-dimethylpropane