A periodic table is needed for this question
A compound has an empirical formula of C2H6O and a molar mass of 92.16.
What is the molecular formula of this compound?
C2H6O
C4H12O2
C6H18O3
C8H24O4
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Syllabus Edition
First teaching 2014
Last exams 2024
A periodic table is needed for this question
A compound has an empirical formula of C2H6O and a molar mass of 92.16.
What is the molecular formula of this compound?
C2H6O
C4H12O2
C6H18O3
C8H24O4
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When lead sulfide reacts with oxygen it produces lead(II)oxide and sulfur dioxide according to the equation below:
PbS(s) + O2(g) → PbO(s) + SO2(g)
What is the whole number sum of the coefficients in the balanced equation?
4
5
8
9
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A compound is made of sulfur and oxygen only. A sample of the compound has a mass of 8.0g, and consists of 3.2g of sulfur and 4.8g of oxygen. The empirical formula of the compound is:
(RAMs S = 32.0, O = 16.0)
SO
SO2
SO3
S2O3
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A sample of chlorine gas with a of mass 5.35 g has a volume of 1.247 × 10-3 m3 at a pressure of 1.00 × 105 Pa.
Assuming that the gas acts as an ideal gas, what is the temperature of the gas in K?
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A periodic table is needed for this question
In which of the following species are the numbers of protons, neutrons and electrons all different?
23Na+
27Al
19F-
32S2-
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The reaction shown occurs in gas clouds throughout the Universe.
H2(g) + H2+(g) → H(g) + H3+(g)
Which is the correct atomic structure of the H3+ ion?
protons |
neutrons |
electrons |
|
A B C D |
3 3 2 2 |
0 0 1 1 |
1 2 1 2 |
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Electron configurations for atoms of different elements are shown below.
Which electron configuration represents the element with the largest first ionisation energy?
1s22s22p63s2
1s22s22p63s23p4
1s22s22p63s23p6
1s22s22p63s23p64s2
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Which of the following statements about 2-methylpropan-2-ol, CH3C(CH3)(OH)CH3, are correct ?
I and II only
I and III only
II and III only
I, II and III
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The following equation shows the dissociation equilibrium of PCl5.
PCl5(g) → PCl3(g) + Cl2(g)
The percentage yield of PCl3 varies with temperature.
At 160°C PCl3 yield is 13% and at 300°C yield is100%.
Which of the following rows is correct?
|
The reaction is |
Shape of PCl3 molecule |
A |
exothermic |
trigonal pyramidal |
B |
exothermic |
trigonal planar |
C |
endothermic |
trigonal pyramidal |
D |
endothermic |
trigonal planar |
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Which of the following metals would have the highest melting point?
Na
Mg
Al
K
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The correct order of increasing boiling points for the following compounds is
1-chlorobutane < butane < butan-1-ol
Butan-1-ol < 1-chlorobutane < butane,
Butane < 1-chlorobutane < butan-1-ol
Butan-1-ol < butane < 1-chlorobutane
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Which equation below can represent both an enthalpy change of formation and combustion?
CH4(g) + 2O2(g) → CO2(g) + 2H2O(l)
2Na(s) + ½O2(g) → Na2O(s)
HCl(aq) + NaOH(aq) → NaCl(aq) + H2O(l)
CO(g) + C(s) → CO2(g)
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Titanium occurs naturally as the mineral rutile, TiO2. One possible method of extraction of titanium is to reduce the rutile by heating with carbon.
TiO2(s) + 2C(s) → Ti(s) + 2CO(g)
The standard enthalpy changes of formation of TiO2(s) and CO(g) are –890 kJ mol-1 and –110.5 kJ mol-1 respectively.
What is the standard enthalpy change of the extraction of titanium?
+ 669 kJ mol–1
+ 779.5 kJ mol–1
– 779.5 kJ mol–1
– 669 kJ mol–1
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In the gas phase, phosphorus pentachloride can be thermally decomposed into gaseous phosphorus trichloride and chlorine.
PCl5 → PCl3 + Cl2
The table below gives the relevant bond energies found in these compounds.
bond |
bond energy / kJ mol–1 |
P–Cl (in both chlorides) Cl–Cl |
|
What is the enthalpy change in the decomposition of the reaction?
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The standard enthalpy change, ΔHӨ, for the following reaction is -246 kJ.
N2(g) + 3F2(g) → 2NF3(g)
The bond energy of N≡N is 945 kJ mol-1 and F–F is 159 kJ mol-1
What is the bond energy of the N–F bond?
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The distribution of molecular energies in a sample of a gas at a given temperature is shown by the Boltzmann distribution graph below.
If the temperature is increased, what will happen to the position of point X?
fewer molecules possess the most probable energy value so X will shift to the right
fewer molecules possess the most probable energy value so X will shift to the left
more molecules possess the most probable energy value so X will shift to the left
the position of X will stay the same but the area under the distribution curve increases
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In a reaction between 1M hydrochloric acid and an excess of marble chips (calcium carbonate) the volume of gas produced was measured against time. This is shown on the dotted line in the graph below.
The experiment was repeated, but this time using the same volume of 2M hydrochloric acid. Which line on the graph represents this experiment?
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Study the following equilibrium reaction and determine which of the statements must be true.
2X ⇋ Y Kc = 1.1
[X] ≫ [Y]
[X] >[Y]
[X] = [Y]
[X] < [Y]
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Some species may be classified as amphiprotic, some as amphoteric and some as both. Which of the following applies to HPO42−?
Amphiprotic but not amphoteric
Amphoteric but not amphiprotic
Amphiprotic and amphoteric
Neither amphiprotic nor amphoteric
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Determine which of the following solutions would be basic at 25 °C?
Kw = 1.0 × 10−14 mol2 dm-6
[H+] = 1.0 × 10−2 mol dm−3
[OH−] = 1.0 × 10−12 mol dm−3
solution of pH = 5.00
[H3O+] = 1.0 × 10−12 mol dm−3
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Oxidation numbers can be used to balance equations. Chlorine and hot aqueous sodium hydroxide react to produce chloride ions, chlorate ions and water.
What are the values of the coefficients p, r and s in the equation?
pCl2(g) + qOH-(aq) → rCl-(aq) + sClO3-(aq) + tH2O(l)
|
p |
r |
s |
A B C D |
3 3 2 2 |
5 6 5 4 |
1 2 1 2 |
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When heated ammonium nitrate, NH4NO3, can decompose explosively.
NH4NO3 → N2O + 2H2O
The nitrogen atoms in NH4NO3 have different oxidation numbers.
What are the oxidation numbers for each of the N atoms when this reaction proceeds?
+4, –4
–2, –4
+4, –6
+2, +6
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Below are three statements about voltaic cells.
The correct statements are
I and II only
I and III only
II and III only
I, II and III
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How many isomers, including structural and stereoisomers, with the formula C5H10 have structures that involve π bonding?
3
4
5
6
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Study the formulae shown below and determine which molecules are isomers of each other
I and II only
I and III only
II and III only
I, II and III
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Xylitol is an artificial sweetener used in toothpastes and chewing gum to improve their taste without impairing dental hygiene.
Which functional groups could be produced if Xylitol is oxidised under suitable conditions?
1 |
alkene |
2 |
aldehyde |
3 |
carboxylic acid |
4 |
ketone |
1 only
2 only
2, 3 and 4
2 and 4
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Isomers X and Y both react with HBr.
A mixture of X and Y is reacted with HBr.
Which three structures represent three different possible products of this reaction?
A |
(CH3)2CHCBr3 |
(CH3)2CBrCHBr2 |
CH3CHBrCHBrCH3 |
B |
(CH3)2CHCBr3 |
(CH3)2CBrCHBr2 |
CH3CBr2CHBrCH3 |
C |
(CH3)2CBrCBr3 |
(CH3)2CHCBr3 |
CH3CBr2CHBrCH3 |
D |
(CH3)2CBrCHBr2 |
CHBr2CBr(CH3)CH3 |
CH3CHBrCBr2CH3 |
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Limonene is an oil formed in the peel of citrus fruits.
Which product is formed when an excess of bromine, Br2(l), reacts with limonene at room temperature in the dark?
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Which alcohol is not likely to have a fragment at m/e at 43 in its mass spectrum?
(CH3)2CHCH2OH
CH3CH(OH)CH2CH2CH3
CH3CH2CH2CH2OH
CH3CH2CH(OH)CH3
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Which of the following statements about propanal, CH3CH2CHO, and propanone, CH3COCH3 is not correct?
The compounds have:
molecular ion peaks at different mass to charge ratios
different fragmentation patterns in the mass spectrum
absorption in the infrared spectrum due to the carbonyl group
a different fingerprint region in the infrared spectrum
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