Which equation below represents deposition?
2Al(s) + 3Br2(g) → 2AlBr3(s)
MgCO3(s) + 2HCl(aq) → MgCl2(aq) + CO2(g) + H2O(l)
I2(g) → I2(s)
HgCl2(s) → HgCl2(g)
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Syllabus Edition
First teaching 2014
Last exams 2024
Which equation below represents deposition?
2Al(s) + 3Br2(g) → 2AlBr3(s)
MgCO3(s) + 2HCl(aq) → MgCl2(aq) + CO2(g) + H2O(l)
I2(g) → I2(s)
HgCl2(s) → HgCl2(g)
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A compound of molar mass 92 gmol-1 contains 12g of carbon, 2g of hydrogen and 32g of oxygen. What is the molecular formula of the compound?
CH2O2
CH2O
C2H4O2
C2H4O4
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A periodic table is needed for this question
A 2.27 dm3 sample of nitrogen gas, measured under standard conditions, reacted with a large excess volume of hydrogen gas to produce ammonia. Only 20.0% of the nitrogen gas reacted to produce ammonia.
What mass of ammonia was made?
0.20 g
0.34 g
0.68 g
1.36 g
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A periodic table is needed for this question
When a 1.00 g sample of carbon is burned in a limited supply of oxygen, 0.72 g of the carbon combusts to form CO2 and 0.28 g of the carbon combusts to form CO.
These gases were passed through excess NaOH(aq) which absorbs the CO2, but not the CO. The remaining gas was then dried and collected.
Assuming that all gas volumes were taken at 25˚C and 100 kPa pressure, what was the volume of gas at the end of the reaction? (Molar Volume of a gas at rtp = 24 dm3)
0.01 dm3
100 cm3
2.40 dm3
240 cm3
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The atomic number of an element gives the number of protons in the nucleus which is also equal to the number of electrons. Which statement explains why atoms are neutral?
one proton has a mass 1840 times greater than one electron
the charge on an electron is equal and opposite to the charge on a proton
the difference in charge between electrons and protons is balanced by the neutrons
electrons are spread out in shells around the nucleus while protons are concentrated inside the nucleus
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Element X is in period 2 and has the first seven ionisation energies in kJ mol-1 as shown.
1300 |
3380 |
5330 |
7460 |
11 010 |
13 320 |
71 200 |
What is the electronic configuration of element X?
1s2 2s2 2p4
1s2 2s2 2p2
1s2 2s2 2p3
1s2 2s2 2p6
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ionic radius | atomic radius | |
A | sodium < sulfur | sodium < sulfur |
B | sodium < sulfur | sodium > sulfur |
C | sodium > sulfur | sodium > sulfur |
D | sodium > sulfur | sodium < sulfur |
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Which statement correctly describes the trend in metallic radius in group I elements
Na to Rb?
I and II only
I and III only
II and III only
I, II and III
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Phosphine, PH3, can react with a hydrogen ion, H+, to form the phosphonium ion.
Which type of bond is formed in this reaction?
dipole-dipole forces
dative covalent bond
ionic bond
hydrogen bond
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Which of the following statements about graphite are correct?
I and II only
I and III only
II and III only
I, II and III
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The properties of alloys can be explained in terms of metals having
I and II only
I and III only
II and III only
I, II and III
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A student mixed 30.0 cm3 of 0.0250 mol dm-3 potassium hydroxide solution with 30.0 cm3 of 0.0250 mol dm-3 nitric acid. The temperature rose by 0.50 oC. Assume no heat was lost to the surroundings.
The mixture had a specific heat capacity of 4.18 J g -1 K-1.
What is the molar enthalpy change for the reaction?
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The reaction of hydrochloric acid with sodium hydroxide produced an overall temperature increase of 24.4 K.
Given the following data, how much thermal energy was evolved during this reaction?
Initial temperature of 25.0 cm3 hydrochloric acid = 17.6 oC
Initial temperature of 25.0 cm3 sodium hydroxide = 18.5 oC
The specific heat capacity of water is 4.18 J g-1 K-1.
(25.0 x 4.18 x 6.8) + (25.0 x 4.18 x 5.9)
50.0 x 4.18 x
(50.0 x 4.18 x 6.8) + (50.0 x 4.18 x 5.9)
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The first stage in the industrial production of nitric acid from ammonia can be represented by the following equation.
4NH3(g) + 5O2(g) ⇌ 4NO(g) + 6H2O(g)
Using the following standard enthalpy change of formation data, what is the value of the standard enthalpy change for this reaction?
Compound |
/kJ mol– 1 |
NH3 (g) |
-46.1 |
NO (g) |
+90.3 |
H2O (g) |
-241.8 |
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Which equation correctly shows how the bond energy for the covalent bond Y–Z can be calculated by dividing ΔH by n?
nYZ(g) → nY(g) + Z2(g)
Z(g) + YZn-1(g) → YZn(g)
2YZn (g) → 2YZn-1(g) + Y2(g)
YZn(g) → Y(g) + nZ(g)
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The dotted-line curve on each graph below represents the corresponding distribution for a gas at 300 K.
Which solid-line curve most accurately represents the distribution of molecular energies in the same gas at 500 K?
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1 dm3 of gas X and 1 dm3 of gas Y are kept at the same temperature and pressure.
The speed of the molecules is plotted against the fraction of molecules with that speed. From the graph what can be said about the two gases?
The molar mass of X is larger than the molar mass of Y
The molar mass of Y is larger than the molar mass of X
The average kinetic energy of X is higher than that of Y
The average kinetic energy of Y is higher than that of X
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Hydrogen reacts with iodine according to the following equation
H2 (g) + I2 (g) ⇋ 2HI (g)
The value of Kc for this reaction has been measured at different temperatures
Kc = 60 at 355 C
Kc = 47 at 450 C
From the information given which of the following must be true?
The reaction is exothermic
The reaction is endothermic
The reaction barely proceeds at 355 C
The reaction almost goes to completion at 450 C
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The following reaction occurs between concentrated sulfuric and nitric acids.
H2SO4 + HNO3 ⇋ H2NO3+ + HSO4-
Identify the two species which are acting as Brønsted–Lowry bases.
H2NO3+ and HSO4-
HNO3 and H2NO3+
H2SO4 and HSO4-
HNO3 and HSO4-
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Calculate the pH of a solution of NaOH of concentration 0.001 mol dm-3
1
3
11
13
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Acid rain can be up to 50 times more acidic than normal rain, which has a pH around 5.5. What is the approximate concentration of H+ in acid rain?
2.50 10-3 mol dm-3
2.50 10-4 mol dm-3
2.50 10-5 mol dm-3
50.0 10-4 mol dm-3
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The chemistry of the Group VII elements often involves redox processes.
Which of the following statements is correct?
Bromine can oxidise chloride ions
Iodide ions are the weakest reducing agent of the first four Group VII ions
In reactions with water, chlorine is oxidised and reduced
Fluorine is a weaker oxidising agent than chlorine
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Below are four descriptions about the movements of electrons in voltaic cells.
Which is the correct statement?
Electrons flow through the external wire from the cathode (positive electrode) to the anode (negative electrode)
Electrons flow through the external wire from the anode (negative electrode) to the cathode (positive electrode)
Electrons flow through the salt bridge from the oxidizing agent to the reducing agent
Electrons flow through the salt bridge from the reducing agent to the oxidizing agent
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How many isomeric esters have the molecular formula C5H10O2?
4
5
9
7
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What is the correct condensed structural formula for 2,2-dibromo-4-methylhexane?
CH3CBr2CH(CH3)CH2CH2CH3
CH3CHBrCBr(CH3)CH2CH2CH3
CH3CBr2CH2CH(CH3)CH2CH3
CH3CHBrCH(CH3)CHBrCH2CH3
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In the presence of ultraviolet light, ethane and chlorine react to give a mixture of products.
Which compound could be present in the mixture of products?
CH3Cl
CH3CH2CH2Cl
CH3CH2CH2CH3
CH3CH2CH2CH2CH3
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Dichlorodifluoromethane, CCl2F2, has been used in aerosol propellants and as a refrigerant.
Which statement helps to explain why dichlorodifluoromethane is chemically inert?
the carbon-fluorine bond energy is large
the carbon-fluorine bond has a low polarity
fluorine is highly electronegative
fluorine compounds are non-flammable
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Samples of 10 cm3 of each of the first four members of the alkane series are separately mixed with 70 cm3 of oxygen. Each is then burned and the total volume, V, of residual gas measured again at room temperature and pressure.
Which graph represents the results that would be obtained?
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Chlorine has two isotopes 35Cl and 37Cl. Assuming in the molecule C4H6Cl4 there is only one hydrogen and one carbon isotope, how many molecular ion peaks will be seen in its mass spectrum?
5
4
3
2
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The mass spectra of three compounds A, B and C are shown below.
What evidence from the spectra of the three compounds A, B and C, suggests they could be isomers?
all show a molecular ion peak at 74
all show a molecular ion peak at 13
all show a molecular ion peak at 73
all show a molecular ion peak at 33
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