CSEC Chemistry Paper 1 May/June 2005 - Free CXC Past Paper with Answers

Which of the following techniques or processes may be used to separate a mixture of plant pigments into its individual components?

Fractional distillation

Paper chromatography

The rate of a chemical reaction does NOT depend on the

concentration of the reactants

presence of a catalyst

temperature of the reacting system

energy change associated with the reaction

Which of the following compounds may be conveniently prepared by precipitation?

Copper (II) sulphate

Which of the atoms represented below by their electronic configuration will most readily form a positive ion?

Particles in a solid cannot move about because the

forces of attraction are very strong

particles are tightly packed together

particles cannot be easily compressed

particles have a high density

Which of the following can behave both as an oxidizing agent and a reducing agent?

Concentrated sulphuric acid

Acidified potassium permanganate (VII) solution

The mixture contains dyes

Which of the following aqueous solutions contains 1 mole of hydrogen ions?

$1 \text{ dm}^3$ of $1.0 \text{ mol dm}^{-3} \text{ H}_2\text{SO}_4$

$1 \text{ dm}^3$ of $1 \text{ mol dm}^{-3} \text{ CH}_3\text{COOH}$

$2 \text{ dm}^3$ of $0.5 \text{ mol dm}^{-3} \text{ H}_2\text{SO}_4$

$2 \text{ dm}^3$ of $0.5 \text{ mol dm}^{-3} \text{ HCl}$

When iron (III) sulphate reacts with aqueous potassium iodide, a brown coloration of iodine is produced. Which of the following deductions is correct?

Iron (III) sulphate is a reducing agent.

The iodide ion has been oxidised to iodine.

The iron (III) sulphate has lost electrons.

The iodide ion has gained electrons.

Sodium metal contains I. $\text{Na}^+$ ions and mobile electrons. II. $\text{Na}^+$ ions and mobile electrons. III. cations which repel each other. IV. anions which repel each other.

Which of the following statements are true? Isotopes of an element contain I. the same number of protons. II. the same number of neutrons. III. different numbers of electrons. IV. the same number of protons as electrons.

Which of the following processes suggests that matter is made up of minute particles?

The two alcohols with identical molar masses are

Which alcohol contains the same number of carbon atoms as methane?

Which of the following statements about chemical reactions is NOT correct?

Energy is given out when bonds break and taken in when bonds form.

Chemical reactions involve the making and breaking of bonds.

Endothermic reactions take energy from the surroundings.

Exothermic reactions give energy to the surroundings.

Which two of the above acids require more than one mole of $NaOH(aq)$ for complete neutralization?

Which of the above substances is the oxide of a metal?

Which of the above substances supplies protons as the only positive ions in aqueous solutions?

In which of the following processes is fractional distillation NOT used?

Refining of crude petroleum

Separation of methanol from a methanol-water mixture

Conversion of alkanes into unsaturated compounds

Separation of liquid air into nitrogen and oxygen

Which two of the following are true about electrons, protons and neutrons in an atom?

I. Protons and neutrons are found in the nucleus. II. Electrons can be found anywhere outside the nucleus. III. The number of protons always equals the number of neutrons. IV. The number of protons always equals the number of electrons.

Which of the following is NOT a mixture?

Which set of elements has molecules which contain two atoms?

The transition elements

Which set of elements has atoms with 2 electrons in their outer shells?

The transition elements

Which of the following factors would NOT be expected to determine whether a particular cation would be discharged during electrolysis?

The position of the cation in the electrochemical series

The concentration of the cation in solution

The inertness of the electrode

The temperature of the solution

Which of the following reactions involve oxidation and reduction?

I. $\text{Mg}(s) + 2\text{H}^+(aq) \rightarrow \text{Mg}^{2+}(aq) + \text{H}_2(g)$ II. $\text{Mg}(s) + 4\text{H}^+ + 2\text{NO}_3^-(aq) \rightarrow \text{Mg}^{2+}(aq) + 2\text{NO}_2(g) + 2\text{H}_2\text{O}(l)$ III. $\text{Ba}^{2+}(aq) + \text{SO}_4^{2-}(aq) \rightarrow \text{BaSO}_4(s)$ IV. $\text{Zn}(s) + \text{Cu}^{2+}(aq) \rightarrow \text{Zn}^{2+}(aq) + \text{Cu}(s)$

Crystals of sodium chloride are BEST referred to as

macromolecular crystals

Which of the following ways can be used to compute the value $-\text{B kJ}$ ?

I. The energy of $\text{Z}$ minus the energy of $\text{X}$ and $\text{Y}$ II. The energy of $\text{X}$ and $\text{Y}$ minus the energy of $\text{Z}$ III. The sum of the energies of $\text{X}$ , $\text{Y}$ and $\text{Z}$

$\text{FeCl}_2$ and $\text{FeCl}_3$ are two chlorides of iron. Which of the following statements about these two chlorides of iron are true?

I. The oxidation state of iron is different in the two chlorides. II. The percentage of iron by mass in the two chlorides is different. III. The colours of the aqueous solutions of the two chlorides are different. IV. The aqueous solutions of the two chlorides do not conduct electricity.

Sulphuric acid forms the sodium salts $\text{NaHSO}_4$ and $\text{Na}_2\text{SO}_4$ . Its basicity is therefore

Barium (Ba) is an element in Group II of the periodic table. It reacts with cold water to give hydrogen and another substance of formula:

can be used in an acid-base titration to show that the reaction has been completed?

in aqueous solution, produces a white precipitate on reaction with sulphuric acid?

Item 33 refers to the table below which gives the melting and boiling points of the chlorides of four elements.

Element	m.p. of chloride/K	b.p. of chloride/K
I	210	453
II	248	348
III	973	1693
IV	193	333

Which of these elements would MOST likely form a chloride that is ionic in nature?

Solid forms of a given element which differ in physical properties

Compounds having the same molecular formula but different structural formulae

Which of the following elements reacts most vigorously with H $^+$ (aq) ions to give hydrogen gas?

Potassium is a metal. From this information ONLY it may be deduced that potassium

has a low melting point

is a good conductor of electricity

The catalyst used in this process is

When copper(II) carbonate is heated alone in a dry test tube a gas is evolved and a black residue is formed. This gas is expected to

relight a glowing splint

turn red litmus blue

decolourize acidified aqueous potassium manganate(VII)

form a white precipitate with aqueous calcium hydroxide

Which of the following aqueous solutions will produce a blue precipitate with aqueous sodium hydroxide?

Which of the following gases are classified as pollutants of the air?

I. Nitrogen II. Carbon monoxide III. Hydrogen IV. Sulphur dioxide

Many fertilisers contain ammonium salts because these salts

are all very soluble in water

improve the texture of the soil

dissolve to give acidic solutions which keep away pests

are a source of nitrogen which is essential to plant growth

Which of the following neither reacts with water, nor displaces hydrogen from dilute hydrochloric acid?

In the reaction between zinc and dilute sulphuric acid

an insoluble salt is formed

neutralisation occurs

oxidation and reduction occur

Which of the following are arranged in order of increasing particle size?

Colloids, solutions, suspensions

Solutions, suspensions, colloids

Suspensions, colloids, solutions

Solutions, colloids, suspensions

Which of the following measurements is NOT required to calculate the enthalpy of combustion?

Mass of the spirit lamp before burning

Mass of the spirit lamp after burning

Initial temperature of the water

Volume of ethanol in the spirit lamp

Which of the following is a major source of error in this experiment?

Heat loss to the surroundings

Incomplete combustion of the ethanol

Evaporation of the ethanol from the wick

Which of the following statements about the reaction $\text{N}_2(g) + 3\text{H}_2(g) \rightleftharpoons 2\text{NH}_3(g)$ is true when the pressure is increased?

The position of equilibrium shifts to the left.

The position of equilibrium shifts to the right.

The value of the equilibrium constant, $K_c$ , increases.

The value of the equilibrium constant, $K_c$ , decreases.

Which of the following statements is true for a reaction that has reached equilibrium?

The concentrations of reactants and products are equal.

The rate of the forward reaction is zero.

The rate of the forward reaction equals the rate of the reverse reaction.

The reaction has stopped.

Which of the following factors will change the value of the equilibrium constant, $K_c$ , for a reversible reaction?

A change in pressure

A change in temperature

The addition of a catalyst

A change in the concentration of the reactants

Which of the following types of polymers may be derived from compounds like the one below?

The process by which large molecules of hydrocarbons are broken up into smaller molecules is called

The fermentation of sugars, using glucose as the substrate, can be represented by the equation

$C_6H_{12}O_6 + 6O_2 \rightarrow 6CO_2 + 6H_2O$

$C_6H_{12}O_6 + C_6H_{12}O_6 \rightarrow C_{12}H_{22}O_{11} + H_2O$

$C_6H_{12}O_6 \rightarrow 2C_2H_5OH + 2CO_2$

$6CO_2 + 6H_2O \rightarrow C_6H_{12}O_6 + 6O_2$

Which of the following BEST describes what will be observed in the U-tube and the test tube at the end of the investigation?

Colourless liquid / Carbon dioxide

Water / White precipitate

Colourless liquid / White precipitate

Water / Carbon dioxide

If the ice were removed, which of the following would represent the equation for the reaction?

$2 \text{C}_2\text{H}_5\text{OH(aq)} + 7 \text{O}_2\text{(g)} \rightarrow 4 \text{CO}_2 \text{(g)} + 6 \text{H}_2\text{O (l)}$

$2 \text{C}_2\text{H}_5\text{OH(l)} + 7 \text{O}_2\text{(g)} \rightarrow 4 \text{CO}_2 \text{(g)} + 6 \text{H}_2\text{O (g)}$

$2 \text{C}_2\text{H}_5\text{OH(aq)} + 7 \text{O}_2\text{(g)} \rightarrow 4 \text{CO}_2 \text{(g)} + 6 \text{H}_2\text{O (aq)}$

$2 \text{C}_2\text{H}_5\text{OH(aq)} + 7 \text{O}_2\text{(g)} \rightarrow 4 \text{CO}_2 \text{(g)} + 6 \text{H}_2\text{O (g)}$

The functional group present in carboxylic acids is

$-C=O$ with an $H$ attached to the $C$

$-C=O$ with an $OH$ attached to the $C$

$-C-OH$ with an $H$ attached to the $C$

$-C=C-OH$ with an $H$ attached to the $C$

Which compound is NOT considered to be a polymer?

The major natural source of alkanes and alkenes is

What will be the colour of the solution in the test tube when the chlorine stream has stopped?

Yellow-green then red-brown

A polymer has the partial structure $-CHXCH_2CHXCH_2CHXCH_2CHXCH_2-$ . The formula of the monomer would be

CSEC Chemistry Paper 1 May/June 2005 - Free CXC Past Paper with Answers

CSEC Chemistry Paper 1 May/June 2005 Questions