Chemistry Random Retrieval Y13

Which is the most typical reaction of an amine in organic synthesis?

This is the ¹H NMR spectrum of:

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 standard enthalpy change when one mole of an ionic compound forms from free gaseous ions is called the:

What enthalpy change is represented by the following equation?

2Na_(s) + ½ O_2(g)=> Na₂O_(s)

From your calculation of ΔG in question 8, decide whether the reaction between high pressure steam and methane will be feasible at 1500^oC.

If this question is from a Random Retrieval, you can also carry out this calculation of Gibbs Energy change, ΔG by first working out values for ΔS^Ɵ and ΔH^Ɵ by selecting the appropriate data from the ‘Selection of Thermodynamic Data’ in TOOLS.

Work out the ratio of the species in the following half-equation.

I₂ + e^- => I^-

I₂ = [1] 1 [2] 2 [3] 3 [4] 4 [5] 5 [6] 6

e^- = [7] 1 [8] 2 [9] 3 [10] 4 [11] 5 [12] 6

I^- = [13] 1 [14] 2 [15] 3 [16] 4 [17] 5 [18] 6

What is the value of E^ϴcell/V observed for a cell constructed from the following half-cells?

Mg²⁺_(aq) + 2e^- <=> Mg_(s) E^ϴcell/V = -2.37

Ag⁺_(aq) + e^- <=> Ag_(s) E^ϴcell/V = +0.80

For this question, look at the resource, ‘A Selection of Standard Electrode Potentials’ (‘A Selection of Standard Electrode Potentials’can be found in TOOLS>Data Sheets)

Which chemical species is the most powerful oxidising agent?

For this question, look at the resource, ‘A Selection of Standard Electrode Potentials’ (‘A Selection of Standard Electrode Potentials’can be found in TOOLS>Data Sheets)

Which chemical species is most resistant to reduction?

Consider a cell constructed from the following half-cells:

Zn²⁺_(aq) + 2e^- <=> Zn_(s) E^ϴ/V = -0.76

Cu²⁺_(aq) + 2e^- <=>Cu_(s) E^ϴ/V = +0.34

Which half-cell will form the cathode in this cell? Think very carefully about the definition of a cathode!

Work out the ratio of the species in the following half-equation.

O₂ + e^- + H⁺ => H₂O

When four bromide ions combine with a cobalt(II) ion

(i) the charge on the complex ion is 2-

(ii) the shape of the complex ion is tetrahedral

(iii) the coordination number of the cobalt atom is 4

(iv) the name of the complex is the tetrabromocobalt (II) ion

Calculate the value of the enthalpy change associated with the following equation?

2Cl_2(g)=> 4Cl_(g)

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?

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.

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

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

This is the ¹H NMR spectrum of:

This is the ¹H NMR spectrum of:

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 types of isomerism are examples of stereoisomerism.

(i) chain isomerism

(ii) E/Zisomerism

(iii) functional group isomerism

(iv) optical isomersim

Step 3:

The monomer which polymerises to form a plastic which has a smooth, slippery surface and is used to give cooking utensils a non-stick surface is:

Which of these compounds are solids at room temperature?

(i) propane

(ii) propanoic acid

(iii) propylamine

(iv) 2-aminopropanoic acid

What is the main organic product when benzene reacts with 2-iodo-2-methylpropane in the presence of aluminium chloride?

Ethyl ethanoate is heated under reflux with excess aqueous sodium hydroxide. The resulting solution is distilled. The distillate contains:

The reaction of propanone with HCN in the presence of some KCN is an example of: