Category: Chemistry

2.82g of lithium carbonate was dissolved in deionised water and made up to 250cm³ in a volumetric flask.

10.0cm³ samples were titrated against hydrochloric acid solution of concentraion 0.100 mol dm^-3.

A mean titre of 28.70cm³ of hydrochloric acid solution was obtained.

Calculate the percentage purity, by mass, of the original solid. (Don't include the % symbol and give answer to 1 decimal place!)

1.98g of lithium carbonate was dissolved in deionised water and made up to 100cm³ in a volumetric flask.

25.0cm³ samples were titrated against hydrochloric acid solution of concentraion 0.500 mol dm^-3.

A mean titre of 25.35cm³ of hydrochloric acid solution was obtained.

Calculate the percentage purity, by mass, of the original solid. (Don't include the % symbol and give answer to 1 decimal place!)

4.95g of potassium hydrogencarbonate was dissolved in deionised water and made up to 100cm³ in a volumetric flask.

10.0cm³ samples were titrated against sulfuric acid solution of concentraion 0.100 mol dm^-3.

A mean titre of 22.05cm³ of sulfuric acid solution was obtained.

Calculate the percentage purity, by mass, of the original solid. (Don't include the % symbol and give answer to 1 decimal place!)

Calculate the pH of a solution created by the addition of 20.0cm³ 0.150 mol dm^-3 barium hydroxide (Ba(OH)₂) solution to 60.0 cm³ 0.200 mol dm^-3 hydrochloric acid solution.

Remember to give your answer to 3 sig.fig.

By titration, it was found that an average titre of 19.95cm³ of 0.180 mol dm^-3 solution of nitric acid was required to just neutralise a 10.00 cm³ sample of sodium carbonate solution. Calculate the concentraion of the sodium carbonate solution.

The equation for the reaction is

2HNO_3(aq)+Na₂CO_3(aq)=>2NaNO_3(aq)+H₂O_(aq)+CO_2(g)

By titration, it was found that an average titre of 16.25cm³ of 0.500 mol dm^-3 solution of sulfuric acid was required to just neutralise a 10.00 cm³ sample of sodium hydroxide solution. Calculate the concentraion of the sodium hydroxide solution.

The equation for the reaction is

2NaOH_(aq)+H₂SO_4(aq)=>Na₂SO_4(aq)+H₂O_(aq)

By titration, it was found that an average titre of 19.75cm³ of 0.200 mol dm^-3 solution of hydrochloric acid was required to just neutralise a 10.00 cm³ sample of lithium hydroxide solution. Calculate the concentraion of the lithium hydroxide solution.

The equation for the reaction is

LiOH_(aq)+HCl_(aq)=>LiCl_(aq)+H₂O_(aq)

By titration, it was found that an average titre of 20.00cm³ of 0.150 mol dm^-3 solution of hydrochloric acid was required to just neutralise a 10.00 cm³ sample of sodium hydroxide solution. Calculate the concentraion of the sodium hydroxide solution.

The equation for the reaction is

NaOH_(aq)+HCl_(aq)=>NaCl_(aq)+H₂O_(aq)

By titration, it was found that an average titre of 45.25cm³ of 0.100 mol dm^-3 solution of hydrochloric acid was required to just neutralise a 20.00 cm³ sample of barium hydroxide solution. Calculate the concentraion of the barium hydroxide solution.

The equation for the reaction is

Ba(OH)_2(aq)+2HCl_(aq)=>BaCl_2(aq)+2H₂O_(aq)

By titration, it was found that an average titre of 25.00cm³ of 0.100 mol dm^-3 solution of hydrochlorc acid was required to just neutralise a 25.00 cm³ sample of sodium hydroxide solution. Calculate the concentraion of the sodium hydroxide solution.

The equation for the reaction is

NaOH_(aq)+HCl_(aq)=>NaCl_(aq)+H₂O_(aq)

If you were asked to prepare 100cm³ of 1.00 mol dm^-3 hydrochloric acid from 2.00 mol dm^-3, what volume (in cm³) of hydrochloric acid would you need to dilute with deionised water to achieve a total volume of 100cm³ of diluted solution?

What volume (in cm³) of deionised water would you need to add to 200cm³ of nitric acid to dilute it from a concentration of 4.00 mol dm^-3 into a concentration of 1.00 mol dm^-3?

Calculate the concentration of NH₄NO₃ in a solution of volume 1.40dm³ that contains 50.0 g of NH₄NO₃

N=14.0 O=16.0 H=1.0

Calculate the concentration of CuSO₄ in a solution of volume 750.00cm³ that contains 170 g of CuSO₄

S=32.1 Cu=63.5.0 O=16.0

Calculate the concentration of KHCO₃ in a solution of volume 0.307dm³ that contains 200 g of KHCO₃

K=39.1 H=1.0 C=12.0 O=16.0

Calculate the concentration of NH₃ in a solution of volume 900cm³ that contains 100 g of NH₃

N=14.0 H=1.0

Calculate the concentration of aluminium sulfate in a solution of volume 250.00cm³ that contains 5.00 g of aluminium sulfate

S=32.1 Al=27.0 O=16.0

Calculate the volume of solution in cm³ that would contain 0.200 mol of hydrochloric acid if the concentration of the solution is 0.900 mol cm^-3

Calculate the volume of solution in cm³ that would contain 0.080 mol of iron (II) nitrate if the concentration of the solution is 0.225 mol cm^-3

Calculate the volume of solution in cm³ that would contain 0.500 mol of H⁺ ions if the concentration of the solution is 0.500 mol cm^-3

Calculate the volume of gas (in dm³) of 1.40 mol of helium if the gas is at a temperature of 3000K and a pressure of 1000000Pa

Calculate the volume of gas (in dm³) of 0.200 mol of neon if the gas is at a temperature of 25^oC and a pressure of 101kPa

Calculate the volume of gas (in cm³) of 0.175 mol of nitrogen if the gas is at a temperature of 800K and a pressure of 1000kPa

Calculate the volume of gas (in m³) of 30.0 mol of hydrogen chloride if the gas is at a temperature of 650K and a pressure of 10.0kPa

Calculate the temperature of a sample of oxygen (in K) if 10.0 mol of oxygen has a volume of 100dm³ and is at a pressure of 200000Pa

Calculate the temperature of a sample of hydrogen (in ^oC) if 1.00 mol of hydrogen has a volume of 24.00dm³ and is at a pressure of 101000Pa

Calculate the temperature of a sample of neon (in K) if 2.00 mol of neon has a volume of 24.00dm³ and is at a pressure of 50000Pa

Calculate the number of moles of gas present at r.t.p in 5.95 m³ of fluorine.

Calculate the number of moles of gas present at r.t.p in 1.20 dm³ of chlorine.

Calculate the number of moles of gas present at r.t.p in 590 cm³ of fluorine.

Calculate the number of moles of P₂O₅ if you have 105 g of P₂O₅

P=31.0 O=16.0

Calculate the number of moles of FeSO₄ . 7H₂O if you have 45.6 g of FeSO₄ . 7H₂O

S=32.1 Fe=55.8 O=16.0 H=1.0

Calculate the number of moles of CuSO₄ if you have 479 g of CuSO₄

S=32.1 Cu=63.5 O=16.0

Calculate the number of moles of F₂ if you have 9.50 g of F₂

F=19.0

Calculate the number of moles of CaCO₃ if you have 7.00 g of CaCO₃

Ca=40.0 C=12.0 O=16.0

Calculate the mass of copper (II) sulfate pentahydrate that you would have if you had 0.100 mol of copper (II) sulfate pentahydrate

S=32.1 Cu=63.5 O=16.0 H=1.0

Calculate the mass of white phosphorus (P₄) that you would have if you had 1.20 mol of white phosphorus (P₄)

P=31.0

Calculate the mass of sodium that you would have if you had 3.00 mol of sodium

Na=23.0

Calculate the mass of FeSO₄ . 7H₂O that you would have if you had 3.00 mol of FeSO₄ . 7H₂O

S=32.1 Fe=55.8 O=16.0 H=1.0

Calculate the mass of H₂O that you would have if you had 1.25 mol of H₂O

O=16.0 H=1.0

What volume of oxygen is required for complete combustion of 1 dm³ of methane?

CH₄ + 2O₂ => CO₂ + 2H₂O

Assume all volumes are measured at the same temperature and pressure:

A piece of magnesium was reacted with an excess of steam. 600cm³ (measured under r.t.p.) of hydrogen were produced.

What was the mass of the piece of magnesium?

What volume (measured under r.t.p.) of hydrogen will be formed if 15.0g of magnesium is reacted with an excess of steam?

NH₃ + O₂ => NO + H₂O

P₄O₁₀+ H₂O => H₃PO₄

The empirical formula of a compound:

calcium hydrogencarbonate

magnesium nitride

Calculate the number of moles of nitrogen molecules (N₂) in 28.0g of nitrogen

Calculate the mass of 1.00 mol of bromine (Br₂) molecules

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

Which of these molecules does NOT consist of one or more chains of amino acids?

(i) The hormone insulin

(ii) The filaments in muscle fibres

(iii) The enzyme in saliva, amylase

(iv) The genetic material, DNA

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

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

What are the units of k for this reaction?

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.

What enthalpy change is represented by the following equation?

S^-_(g) + e^-=> S^2-_(g)

What enthalpy change is represented by the following equation?

Cl_(g) + e^-=> Cl^-_(g)

Using oxidation numbers (states) work out the ratio of the species in the following half-equation.

MnO₄^- + H ⁺ + e^- => Mn²⁺ + H₂O

Consider a cell constructed from the following half-cells:

Fe³⁺_(aq) + e^- <=> Fe²⁺_(aq) E^ϴ/V = +0.77

MnO₄^-_(aq) + 8H⁺_(aq) + 5e^- <=> Mn²⁺_(aq) + 4H₂O_(aq) E^ϴ/V = +1.51

If the solution of Fe²⁺_(aq) was 2.00 mol dm^-3, would you expect to see a greater or smaller value of E^ϴcell/V than you would if the cell was set-up under standard conditions?

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?

Thinking carefully about the definitions of anode and cathode in electrochemical cells, an anode is defined as (CARE!):

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

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

What are the units of k 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 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:

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.

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:

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 statement helps to explain why propene react with hydrogen bromide to form mainly 2-bromopropane and much less 1-bromopropane?

If the molecule shown below is hydrolysed in hot sodium hydroxide, what are the main organic products?

Which of the following molecules would you predict to be the least nucleophilic?

Which of the following molecules would you predict to be the most basic?

What is the systematic name of the following molecule?

CH₃CH₂CH₂C(NH₂)CHCH₃

What is the reagent used to convert benzene to nitrobenzene?

The reaction using a mixture of benzene and ethene in the presence of hydrogen chloride and aluminium chloride produces an important intermediate in the manufacture of:

Treating ethanal with hydrogen cyanide in the presence of some KCN and then hydrolysing the product with hot hydrochloric acid (which converts a cyano / nitrile group RCN, to RCOOH) produces:

Which types of alcohol, when heated under reflux with acidified potassium dichromate(VI), turn the colour of the solution from orange to green?

Infra-red absorption ranges for some bonds are as follows:

C-H, 2850 - 3300 cm^-1

C=C, 1620 - 1680 cm^-1

C=O, 1680 - 1750 cm^-1

C-O, 1000 - 1300 cm^-1

O-H (alcohols), 3230 - 3550 cm^-1

O-H (acids), 2500 - 3000 cm^-1

The IR spectrum of propanal has one particularly strong absorption peak

This can be expected to be at:

Choose one of the following options:

What are the standard conditions for measuring standard enthalpy changes?

How many electrons are there in an oxide ion?

How many p electrons are there in the outer shell of a halogen atom?

Which of these sets of properties is that of an ionic compound?

A chloride ion and an argon atom have the same:

(i) number of protons

(ii) number of electrons

(iii) atomic number

(iv) electron configuration

Which of these compounds is an acid?

Which of these conversions are reductions?

(i) CrO₄^2- to Cr₂O₇^2-

(ii) CrO₄^2- to Cr³⁺

(iii) CrO₄^2- to CrO₃

(iv) CrO₃ to Cr₂O₃

Which of these conversions are reductions?

(i) CrO₄^2- to Cr₂O₇^2-

(ii) CrO₄^2- to Cr³⁺

(iii) CrO₄^2- to CrO₃

(iv) CrO₃ to Cr₂O₃

In a titration, 25 cm³ of 0.100 mol dm^-3 potassium hydroxide was neutralised by 12.5 cm³ dilute nitric acid. What was the concentration of the nitric acid?

Which of these reactions is an acid-base reaction?

Steel and graphite are similar in that they both.

(i) conduct electricity

(ii) are dark grey/black when powdered

(iii) can have high tensile strength

(iv) are brittle

Which of these statements are true for the hydrides of group 5: NH₃, PH₃, AsH₃ and SbH₃:

(i) the molecules decrease in size down the group

(ii) the boiling point of ammonia is higher than expected from the general trend in values down the group

(iii) none of the molecules is polar

(iv) only ammonia is affected by hydrogen bonding

What is the empirical formula of an oxide of sodium which contains 74.2% sodium?

How many moles of molecules are there in 0.240 g bromine?

The first five ionisation energies of an element in kJ/mol are: 419, 3051, 4412, 5877, 7975. The element is in:

What is the electron configuration of sulfur?

The particle with 3 protons, 4 neutrons and 2 electrons is a:

Using mean bond dissociation enthalpies, estimate the enthalpy of combustion Δ_cH of liquid ethanol

C₂H₅OH_(l) + 3O_2(g) => 2CO_2(g) + 3H₂O_(l)

Using enthalpies of formation Δ_fH, calculate the enthalpy change for the following hydration process.

Na₂S₂O_3(s) + 5H₂O_(l) => Na₂S₂O₃•5H₂O_(s)

Select the data from the 'Selection of Enthalpies of Formation and Combustion' shown above.

If this question was generated from Random Retrieval, this data can also be found in TOOLS>Data Sheets.

Chlorine disproportionates when it reacts with:

In which of these molecules do the intermolecular forces arise largely from attractions between temporary dipoles?

A white crystalline solid gives a pale green colour in a flame. Adding silver nitrate to an acidified solution of the solid produces a white precipitate. The solid is:

What is the electron configuration of a magnesium atom?

What is the oxidation number of OXYGEN in hydrogen peroxide

H₂O₂

What is the oxidation number of CARBON in methanol

CH₃OH

What is the oxidation number of NITROGEN in

NH₄⁺

What is the oxidation number of BROMINE in

BrO^-

How many functional group isomers of C₄H₈ are there?

There are two main peaks in the infra-red spectrum of carbon dioxide.

This shows that carbon dioxide molecules:

Products formed by heating 2-bromo-3-methylbutane with a solution of potassium hydroxide in ethanol (an elimination reaction) include:

(i) 2-methylbut-1-ene

(ii) 3-methylbut-2-ene

(iii) 2-methylbut-3-ene

(iv) 3-methylbut-1-ene

What are the conditions for converting 1,2-dichlorethane into ethane-1,2-diol?

Which of these alcohols is a tertiary alcohol?

(i) CH₃CH₂CHOHCH₃

(ii) CH₃CH(CH₃)CHOHCH₃

(iii) CH₃C(CH₃)₂CH₂CHOHCH₃

(iv) (CH₃)₃COH

Why is ethanol a liquid while propane is a gas? (Relative atomic masses: C = 12, H = 1, O = 16)

Which alkene polymerises to form this polymer?---CH(CH₃)CH₂CH(CH₃)CH₂CH(CH₃)CH₂---

Which of these alkenes shows E/Z isomerism?

How many monosubstitution products can be formed when butane reacts with chlorine?

Which of these alkenes shows E/Z isomerism?

Which of these alcohols is oxidised to a ketone by a hot acidic solution of potassium dichromate(VI)?

(i) (CH₃)₃COH

(ii) CH₃CH₂CHOHCH₃

(iii) CH₃CH₂CH₂CH₂OH

(iv) CH₃C(CH₃)₂CH₂CHOHCH₃

An element which consists of a giant structure of atoms held together by covalent bonding is:

In the periodic table a periodic pattern is:

What is the oxidation number of OXYGEN in hydrogen peroxide

H₂O₂

How many shared pairs of electrons are there in an ethene molecule, C₂H₄?

In a close-packed metal structure:

(i) there are no spaces between the atoms

(ii) the atoms are arranged in layers

(iii) the crystal breaks if the layers slide past each other

(iv) each atom touches 12 nearest neighbours.

Which of these changes are redox reactions?

(i) NaCl_(s) + H₂SO_4(l) -> HCl_(g) + NaHSO_4(s)

(ii) NH_3(g) + HCl_(g) -> NH₄Cl_(s)

(iii) CaCO_3(s) -> CaO_(s) + CO_2(g)

(iv) 2HBr_(g) + H₂SO_4 (l) -> Br_2(l) + SO_2(g) + 2H₂O_(l)

A compound P, C₄H₈O, gave on oxidation an acid C₄H₈O₂. Which of the following are possible structures for P?

(i)CH₃CH₂CH₂CHO

(ii)CH₃COCH₂CH₃

(iii) (CH₃)₂CHCHO

(iv) CH₃CH=CHCH₂OH

Which of these compounds are functional group isomers?

(i) CH₃CHCHOH

(ii) CH₃CH₂CHO

(iii) CH₃COCH₃

(iv) CH₃CH₂COCH₃

What is the organic product when benzene reacts with ethanoyl chloride in the presence of aluminium chloride?

Mixing poly(chloroethene) with a plasticiser makes is suitable for use as:

(i) window frames

(ii) insulation for electric cables

(iii) water pipes

(iv) waterproof clothing

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

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.

What enthalpy change is represented by the following equation?

S^-_(g) + e^-=> S^2-_(g)

Look at the chemical equation below.

CH_4(g) + H₂O_(g)=> CO_(g)+ 3H_2(g)

Using your answers to Questions 6 and 7, calculate the Gibbs Energy change ΔG, for the process if it is carried out in a reactor vessel at 1500^oC.

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

Which first-row d-block metal forms aqueous ions in the +6 state which are orange in acid solution but yellow in alkaline solution?

For this question, look at the resource, ‘A Selection of Standard Electrode Potentials’ (For this quiz, you will need to open or download the Data Sheet, ‘A Selection of Standard Electrode Potentials’. This can be found in TOOLS>Data Sheets)

Which chemical species is the most powerful reducing agent?

Which of these changes are redox reactions?

(i) NaCl_(s) + H₂SO_4(l) -> HCl_(g) + NaHSO_4(s)

(ii) NH_3(g) + HCl_(g) -> NH₄Cl_(s)

(iii) CaCO_3(s) -> CaO_(s) + CO_2(g)

(iv) 2HBr_(g) + H₂SO_4 (l) -> Br_2(l) + SO_2(g) + 2H₂O_(l)

Which of these acids is only slightly ionised in aqueous solution?

(i) hydrochloric acid

(ii) nitric acid

(iii) sulfuric acid

(iv) ethanoic acid

Which of these compounds is an acid?

Which of these compounds consists of a giant structure of ions?

Which of these bonds are polar covalent bonds?

(i) C-C

(ii) H-Br

(iii) N-N

(iv) C=O

What is/are the bond angle(s) found in iodine trifluoride?

(i) 104.5^o

(ii) 120^o

(iii) 107^o

(iv) 90^o

Which of these molecules are overall polar?

(i) CH₃Cl

(ii) CH₂Cl₂

(iii) CHCl₃

(iv) CCl₄

Which of these sets of properties is that of a substance which is molecular?

How many filled orbitals are there in the neon atom?