Category: Chemistry

18.4g of citric acid monohydrate (C₆H₈O₇.H₂O), a tribasic acid, was dissolved in deionised water and made up to 250cm³ in a volumetric flask.

10.0cm³ samples were titrated against potassium hydroxide solution of concentraion 0.500 mol dm^-3.

A mean titre of 20.20cm³ potassium hydroxide 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!)

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!)

3.94g 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 0.150 mol dm^-3.

A mean titre of 11.70cm³ 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!)

1.04g of sodium hydroxide was dissolved in deionised water and made up to 100cm³ in a volumetric flask.

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

A mean titre of 22.10cm³ 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!

2.49g of potassium hydroxide was dissolved in deionised water and made up to 250cm³ in a volumetric flask.

20.0cm³ samples were titrated against hydrochloric acid solution of concentraion 0.150 mol dm^-3.

A mean titre of 21.90cm³ 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!)

1.56g of lithium hydroxide was dissolved in deionised water and made up to 250cm³ in a volumetric flask.

25.0cm³ samples were titrated against sulfuric acid solution of concentraion 0.100 mol dm^-3.

A mean titre of 23.20cm³ 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!)

2.5g of potassium hydroxide was dissolved in deionised water and made up to 250cm³ in a volumetric flask.

25.0cm³ samples were titrated against nitric acid solution of concentraion 0.150 mol dm^-3.

A mean titre of 18.15cm³ of nitric 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!)

By titration, it was found that an average titre of 26.25cm³ of 1.100 mol dm^-3 solution of sulfuric acid was required to just neutralise a 25.00 cm³ sample of barium hydroxide solution. Calculate the concentraion of the barium hydroxide solution.

The equation for the reaction is

H₂SO_4(aq)+Ba(OH)_2(aq)=>BaSO_4(aq)+2H₂O_(aq)

By titration, it was found that an average titre of 19.10cm³ of 0.250 mol dm^-3 solution of sulfuric acid was required to just neutralise a 10.00 cm³ sample of potassium hydroxide solution. Calculate the concentraion of the potassium hydroxide solution.

The equation for the reaction is

2KOH_(aq)+H₂SO_4(aq)=>K₂SO_4(aq)+H₂O_(aq)

If you were asked to prepare 104cm³ of 0.389 mol dm^-3 ethanoic acid from 0.800 mol dm^-3, what volume (in cm³) of ethanoic acid would you need to dilute with deionised water to achieve a total volume of 104cm³ of diluted solution?

If you were asked to prepare 500cm³ of 0.500 mol dm^-3 nitric acid from 2.00 mol dm^-3, what volume (in cm³) of nitric acid would you need to dilute with deionised water to achieve a total volume of 500cm³ of diluted solution?

Calculate the concentration of glucose in a solution of volume 1.50dm³ that contains 600 g of glucose

H=1.0 C=12.0 O=16.0

Calculate the concentration of NH₄NO₃ in a solution of volume 0.724dm³ that contains 50.0 g of NH₄NO₃

N=14.0 O=16.0 H=1.0

Calculate the concentration of Ba(NO₃)₂ in a solution of volume 1350cm³ that contains 76.0 g of Ba(NO₃)₂

Ba=137.3 N=14.0 O=16.0

Calculate the concentration of iodine in a solution of volume 2.40dm³ that contains 100 g of iodine

I=126.9

Calculate the concentration of sodium hydroxide in a solution of volume 0.375dm³ that contains 30.0 g of sodium hydroxide

Na=23.0 O=16.0 H=1.0

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 solution in dm³ that would contain 0.300 mol of H⁺ ions if the concentration of the solution is 2.00 mol dm^-3

Calculate the number of moles of potassium chloride in a solution of volume 0.90 dm³ and a concentration of 0.0125 mol dm^-3

Calculate the volume of gas (in m³) of 0.100 mol of hydrogen if the gas is at a temperature of 473K and a pressure of 150000Pa

Calculate the volume of gas (in m³) of 1.00 mol of hydrogen if the gas is at a temperature of 298K and a pressure of 101000Pa

Calculate the temperature of a sample of butane (in ^oC) if 2.88 mol of butane has a volume of 345dm³ and is at a pressure of 190000Pa

Calculate the temperature of a sample of sulfur hexafluoride (in K) if 0.105 mol of sulfur hexafluoride has a volume of 6000cm³ and is at a pressure of 120000Pa

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 butane (in ^oC) if 0.110 mol of butane has a volume of 879cm³ and is at a pressure of 700kPa

Calculate the number of moles of gas present at r.t.p in 240 cm³ of fluorine.

Calculate the number of moles of gas present at r.t.p in 1.50 m³ of oxygen.

Calculate the number of moles of gas present at r.t.p in 3.00 dm³ of gaseous ammonia.

0.248g of gas was collected. The volume of gas was recored as 210 cm³ at a temperature of 100^oC and a pressure of 108kPa

Determine the relative formula mass of the chemical.

Calculate the number of moles of phosphorus (V) oxide (P₄O₁₀) if you have 80.0 g of phosphorus (V) oxide (P₄O₁₀)

P=31.0 O=16.0

Calculate the number of moles of calcium carbonate if you have 60.0 g of calcium carbonate

Ca=40.1 C=12.0 O=16.0

Calculate the number of moles of sodium if you have 34.5 g of sodium

Na=23.0

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 C₂H₆ if you have 75.0 g of C₂H₆

C=12.0 H=1.0

Calculate the mass of propene that you would have if you had 0.0500 mol of propene

C=12.0 H=1.0

Calculate the mass of potassium hydrogen carbonate that you would have if you had 3.00 mol of potassium hydrogen carbonate

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

Calculate the mass of anydrous copper (II) sulfate that you would have if you had 6.10 mol of anydrous copper (II) sulfate

S=32.1 Cu=63.5 O=16.0

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 Cl₂ that you would have if you had 4.00 mol of Cl₂

Cl=35.5

Zinc metal reacts with hydrochloric acid

Zn+ 2HCl=>ZnCl₂+H₂

What volume of H₂ (measured at r.t.p.) would be produced by reaction of 1 litre of 0.5 mol dm^-3 HCl with an excess of zinc?

[1] ½ dm³

[2] 6 dm³

[3] 12 dm³

[4] 24 dm³

When ammonia gas is passed over heated iron wool it decomposes completely into nitrogen and hydrogen

2NH₃ <=>N₂ + 3H₂

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

250cm³ of ammonia was passed, forwards and backwards, over heated iron wool from one graduated syringe to another until there was no further volume change.

What was the final volume of gas in the syringes?

Given this equation,

2Al+Fe₂O₃=>Al₂O₃+2Fe

what mass of aluminium would react completely with 320g of iron (lll) oxide?

nitrogen trifluoride

Work out the formula of each of the following ionic compounds. Use the data sheet ‘Names & Formulae of Some Common Ions’

Use upper case letter I for roman numerals e.g. (II)

Formulae are Case Sensitive.

Use regular numbers in formulae e.g. H2O not H₂O

lithium bromide

Calculate the volume in cm³ of 0.100 mole of osmium atoms (density of Os = 22.5gcm^-3) Osmium is the most dense of all the elements

Calculate the volume in cm³ of 0.500 mole of lithium atoms (density of Li = 0.534gcm^-3) Lithium is the least dense of all the metallic elements (hint: look at the units!)

Calculate the mass of 0.500 mol of sulfur atoms

Calculate the relative molecular mass (formula mass) of zinc hydroxide, Zn(OH)₂

Calculate the relative atomic mass (to one decimal place) of element, C if element C is a mixture of two isotopes, ⁸⁵C and ⁸⁷C, with the abundances 72.15% and 27.85% respectively.

Glycine reacts with dilute hydrochloric acid to form:

Which of these changes represents a termination step of a chain reaction?

(i) CH₃^. + CH₃^. -> CH₃CH₃

(ii) CH₃^. + Br₂ -> CH₃Br + Br^.

(iii) Br^. + Br^. -> Br₂

(iv) Br^. + CH₄ -> CH₃^. + HBr

In which of these reactions between pairs of reagents is the bond breaking homolytic?

(i) butan-1-ol with sodium bromide and concentrated sulfuric acid

(ii) catalytic cracking of hydrocarbons

(iii) bromine with ethene

(iv) bromine with hexane

The rate equation for the reaction of hydroxide ions with 2-bromo-2-methylpropane takes the form:

rate = k[C₄H₉Br].

This indicates that:

(i) the rate determining step involves hydroxide ions

(ii) doubling the concentration of the halogenoalkane doubles the rate of reaction

(iii) the reaction takes place in one step

(iv) the reaction takes place by the S_N1 mechanism (a 2 step mechanism)

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.

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.

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

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

H₂SO₄ + H⁺ + e^- => SO₂ + H₂O

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

H₂O₂ + H⁺ + e^- => H₂O

Salt bridges are required for a cell E^ϴcell/V to be measured.

What statement best describes the action of a salt bridge?

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?

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

MnO₄^- + H ⁺ + e^- => Mn²⁺ + H₂O

Which of these complex ions acts as an acid in aqueous solution?

(i) [Ni(NH₃)₆]²⁺

(ii) [Al(H₂O)₂(OH)₄]^-

(iii) [Ag(NH₃)₂]⁺

(iv) [Cr(H₂O)₆]3⁺

Which first-row d-block metal forms hydrated ions in the +3 state which undergo a ligand exchange reaction to form a deep red complex ion with thiocyanate ions, SCN^-.

Look at the chemical equation below.

CH_4(g) + H₂O_(g)=> CO_(g)+ 3H_2(g)

By selecting the appropriate data from the ‘Selection of Thermodynamic Data’ in TOOLS, calculate the entropy change, ΔS^Ɵ for the process. Take care with states!

The magnitude (numerical value) of the lattice enthalpy for these compounds increase from left to right putting first the compound with the least negative value?

(i) LiCl - LiBr - LiI

(ii) MgO - BaO - BaS

(iii) NaCl - KCl - RbCl

(iv) NaF - MgF₂ - AlF₃

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 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.

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

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

This is the ¹H NMR spectrum of:

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

The rate equation for the reaction of hydroxide ions with 2-bromo-2-methylpropane takes the form:

rate = k[C₄H₉Br].

This indicates that:

(i) the rate determining step involves hydroxide ions

(ii) doubling the concentration of the halogenoalkane doubles the rate of reaction

(iii) the reaction takes place in one step

(iv) the reaction takes place by the S_N1 mechanism (a 2 step mechanism)

The relative rates of hydrolysis for these halogenoalkanes are in the order

C₄H₉I > C₄H₉Br > C₄H₉Cl

This trend correlates with the:

Step 6:

Step 9:

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

What are the products of the acid hydrolysis of methyl propanoate?

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

A sample of propan-2-ol was heated under reflux with an acidified, aqueous solution of potassium dichromate(VI). The resulting mixture was then distilled. The distillate contained:

(i) propanoic acid

(ii) propanone

(iii) propanal

(iv) water

What is made by heating propan-1-ol under reflux with excess of a hot acidic solution of potassium dichromate(VI) and then distilling off the product?

Choose one of the following options:

Which of these statements about atomic and ionic radii are true?

(i) Atomic radii increase down group 2

(ii) Ionic radii increase down group 7

(iii) Atomic radii decrease across period 3

(iv) In period 3 the ionic radii are smaller than the atomic radii

What is the oxidation number of CHROMIUM in

Cr₂O₇^2-

What is the oxidation number of CARBON in methanal

CH₂O

What is the oxidation number of CARBON in methanoic acid

HCOOH

Which of the following increase from left to right across the series F₂ - Cl₂ - Br₂?

(i) covalent radius of the atoms

(ii) electronegativitiy

(iii) boiling point

(iv) strength as an oxidising agent

Which of these materials consist of a giant structure of ions?

(i) magnesium oxide

(ii) silicon dioxide

(iii) potassium fluoride

(iv) silicon chloride

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

The oxidation number of vanadium in the VO²⁺ ion is:

The oxidation number of vanadium in the VO²⁺ ion is:

Which of these gases behaves very much like an ideal gas at room temperature and pressure?

(i) helium

(ii) oxygen

(iii) hydrogen

(iv) butane

Which of these processes are endothermic?

(i) water freezing

(ii) ethanol evaporating

(iii) steam condensing

(iv) wax melting

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

Which of these compounds consist of molecules which are linear?

(i) water

(ii) beryllium chloride

(iii) sulfur dioxide

(iv) carbon dioxide

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

What is the electron configuration of an oxide ion?

How many sulfate ions are there in 0.01 mol aluminium sulfate?

(The Avogadro constant = 6.02 x 10²³ mol^-1)

The synthesis of sulfur trioxide takes place at 380 ^oC in the presence of a catalyst made from vanadium(V) oxide.

2SO_2(g) + O_2(g) <=> 2SO_3(g) Standard enthalpy change = -297 kJ mol^-1

Reasons for not choosing a lower temperature are that:

(i) the product condenses to a solid at a lower temperature

(ii) the proportion of SO_3(g) at equilibrium falls if the temperature falls

(iii) the reaction is exothermic

(iv) the catalyst is ineffective at lower temperatures

For which of these equilibria does a change in pressure have no effect on the yield of substances on the right-hand side of the equation?

(i) CH_4(g) + H₂O_(g) <=> 3H_2(g) + CO_(g)

(ii) 2HI_(g) <=> H_2(g) + I_2(g)

(iii) 2SO_2(g) + O_2(g) <=> 2SO_3(g)

(iv) H₂O_(g) + CO_(g) <=> H_2(g) + CO_2(g)

Using enthalpies of formation Δ_fH, calculate the enthalpy change for the following esterification reaction.

CH₃COOH_(l) + C₂H₅OH_(l) => CH₃COOCH₂CH_3(l) + H₂O_(l)

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.

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

2NaHCO_3(s) => Na₂CO_3(s) + H₂O_(l) + CO_2(g)

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.

The standard enthalpy of combustion of methane is -890 kJ mol^-1. Calculate the energy given out on burning 3.2 g methane.

Which of the following properties increase from left to right across the series: AgCl - AgBr - AgI?

(i) intensity of colour

(ii) solubility in ammonia solution

(iii) ease of oxidation to the halogens

(iv) solubility in aqueous ammonia

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

What is the oxidation number of CARBON in methanol

CH₃OH

Across period 3 from sodium to argon:

(i) the metal with the lowest melting point is sodium

(ii) the element with the highest melting point is silicon

(iii) the non-metal with the lowest melting point is argon

(iv) the melting points of all the non-metals are lower than those of the metals

In the periodic table the elements are arranged in order of:

(i) atomic number

(ii) mass number

(iii) number of protons in the nucleus

(iv) number of protons and neutrons in the nucleus.

Choose one of the following options:

Choose one of the following options:

Which of the following statements describe molecules that are structural isomers?

(i) molecules whose atoms have the same arrangement in space

(ii) molecules that have the same molecular formula

(iii) molecules in which the atoms are joined to the same neighbouring atoms

(iv) molecules which the same atoms but they are bonded in a different order

The peak with the largest mass to charge ratio in the mass spectrum of an alkane is detected at mass-to-charge ratio = 58.

This shows that the hydrocarbon:

The mass spectrum of chlorine includes three peaks at mass-to-charge ratios of 70, 72 and 74.

The order of the heights of these peaks is:

Which is the correct sequence of events that takes place in a modern mass spectrometer in the production of a mass spectrum from a sample of an element or compound?

Which of these alcohols are isomers of butan-1-ol?

(i) CH₃CH₂CHOHCH₃

(ii) (CH₃)₃COH

(iii) CH₃CH(CH₃)CH₂OH

(iv) (CH₃)₃CCH₂OH

An alcohol consists of 64.9% carbon, 13.5% hydrogen and 21.6% oxygen.

What is the molecular formula of the compound? (Relative atomic masses: C = 12, H = 1, O = 16)

The reaction that has the greatest atom economy is:

One mole of an alkane needs 8 moles of oxygen for complete combustion. What is the molecular formula of the alkane?

Choose one of the following options:

Choose one of the following options:

Choose one of the following options:

Bubbling carbon dioxide into an aqueous solution of calcium hydroxide produces a white precipitate of:

An example of an endothermic change is the:

The synthesis of sulfur trioxide takes place at 380 ^oC in the presence of a catalyst made from vanadium(V) oxide.

2SO_2(g) + O_2(g) <=> 2SO_3(g) Standard enthalpy change = -297 kJ mol^-1

Reasons for not choosing a lower temperature are that:

(i) the product condenses to a solid at a lower temperature

(ii) the proportion of SO_3(g) at equilibrium falls if the temperature falls

(iii) the reaction is exothermic

(iv) the catalyst is ineffective at lower temperatures

What is the molar mass of calcium hydroxide?

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

(i) 104.5^o

(ii) 120^o

(iii) 107^o

(iv) 90^o

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.

The amount in moles of iodide ions oxidised by one mole of chlorine molecules is:

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

In a peptide made up of a sequence of four amino acids the number of peptide bonds is:

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:

Step 3:

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:

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

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.

Look at the chemical equation below.

CH_4(g) + H₂O_(g)=> CO_(g)+ 3H_2(g)

Calculate the temperature at which this process just becomes feasible.

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.

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

S₂O₃^2- + H₂O => SO₄^2- + H⁺ + e^-

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

Cu => Cu²⁺ + e^-

What volume of 0.10 mol dm^-3 hydrochloric acid is needed to neutralise 20.0 cm³ of 0.05 mol dm^-3 barium hydroxide?

Which of these true statements can help to explain why magnesium has a higher melting point than sodium:

(i) magnesium atoms/ions are smaller than sodium atoms/ions

(ii) the metallic bonds are stronger in magnesium than in sodium

(iii) a magnesium atoms contributes two bonding electrons not one

(iv) the first ionisation energy is higher for magnesium than for sodium.

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.

In which of these solids are there two types of bonding: one strong and one weak?

(i) diamond

(ii) ice

(iii) sodium chloride

(iv) graphite

Which of these materials owe their strength to intermolecular forces?

Which of these elements consist of a giant structure of atoms joined by covalent bonding?

(i) graphite

(ii) sulfur

(iii) diamond

(iv) iodine

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

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

How many complete shells are there in the zinc atom?

E represents an atom of an element in the equation: E_(g) -> E⁺_(g) + e^– Which of these statements is/are true:

(i) the element must be a metal

(ii) the enthalpy change for this process is the first ionisation energy of the element

(iii) the element must be a gas at room temperature.

(iv) this process occurs in a mass spectrometer used to analyse the element