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‘The movement of a substance very slowly from an area of high concentration to an area of low concentration.’
Which process is being described?
503
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Oxygen melts at $-219^{\circ}\text{C}$ and boils at $-183^{\circ}\text{C}$.
At which temperature is oxygen a liquid?
518
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516
In the chromatography experiment shown, which label represents the solvent front?
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Different methods of separation rely on substances having different properties. Which property does distillation make use of?
530
572
512
Which statement about atomic structure is correct?
519
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507
The structure of propane, $C_3H_8$, is shown.
How many electrons are involved in the bonding of propane?
536
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568
Rubidium is in Group I of the Periodic Table and bromine is in Group VII.
Rubidium reacts with bromine to form an ionic compound.
Which row shows the electron change taking place for rubidium and the correct formula of the rubidium ion?
[Table]
| electron change | formula of ion formed | |
|---|---|---|
| A | electron gained | $\text{Rb}^+$ |
| B | electron gained | $\text{Rb}^-$ |
| C | electron lost | $\text{Rb}^+$ |
| D | electron lost | $\text{Rb}^-$ |
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Which statement explains why graphite is used as a lubricant?
526
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587
The formula of which compound contains the largest number of Group VII atoms?
517
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581
The relative atomic mass of chlorine is 35.5.
When calculating relative atomic mass, which particle is the mass of a chlorine atom compared to?
539
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Universal indicator solution is added to a neutral solution of concentrated aqueous sodium chloride. The solution, which contains $\text{H}^+$ (hydrogen), $\text{Na}^+$ (sodium), $\text{Cl}^-$ (chloride) and $\text{OH}^-$ (hydroxide) ions, is electrolysed. The product at the cathode is hydrogen gas and the product at the anode is chlorine gas. What happens to the colour of the indicator in the solution during electrolysis?
550
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505
Which energy level diagram represents an endothermic reaction?
533
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590
Which process is a physical change?
503
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577
Which substance does not require oxygen in order to produce energy?
586
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Nitrogen, \( N_2 \), and hydrogen, \( H_2 \), can be converted into ammonia, \( NH_3 \), using a catalyst. What is the purpose of the catalyst?
585
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A reaction is carried out at four different temperatures. The time taken for the reaction to complete at each temperature is measured. The results are shown.
What is the relationship between temperature and rate of reaction?
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During the manufacture of sulfuric acid, sulfur dioxide is converted to sulfur trioxide.
$2SO_2 + O_2 \rightarrow 2SO_3$
Which type of reaction is this?
571
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When pink crystals of cobalt(II) chloride are heated, steam is given off and the colour of the solid changes to blue.
$\text{CoCl}_2\cdot 6\text{H}_2\text{O} \rightleftharpoons \text{CoCl}_2 + 6\text{H}_2\text{O}$
What happens when water is added to the blue solid? [Table_1]
589
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591
Which statement describes how a flame test is done?
559
526
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A student carries out an experiment to prepare pure magnesium sulfate crystals.
The diagram shows the first stage of the preparation.
He adds magnesium carbonate until no more reacts.
Which process should he use for the next stage?
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Which row about elements in the Periodic Table is correct? [Table_1]
550
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Tennessine, Ts, is a newly discovered element. The atomic number of tennessine is 117 and it is placed directly underneath astatine in Group VII of the Periodic Table.
The trends in properties of Group VII elements are shown.
[Table_1]
Which statement about the properties of tennessine is likely to be correct?
568
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A flammable gas needs to be removed from a tank at an industrial plant. For safety reasons, an inert gas is used.
Which gas is suitable?
569
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A substance, X, has the following properties.
1. It has a high melting point.
2. It conducts electricity in the solid and liquid states.
3. It is malleable.
4. It has a high density.
What is X?
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Which diagram best represents the structure of a substance that is a good conductor of electricity at 25°C?
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Some properties of element Y are listed.
• It reacts with hydrochloric acid to make hydrogen gas.
• It reacts with steam but not with cold water.
• The oxide of Y cannot be reduced by carbon.
What is element Y?
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Oxides of nitrogen are given out from car exhausts. Which row best shows why oxides of nitrogen are unwanted in the atmosphere?
[Table_1]
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Water is purified using several processes.
Four of the processes are listed.
1. Chlorine is added to water to kill any bacteria.
2. Water is passed through coarse gravel to remove large pieces of dirt.
3. Water is passed through wire screens to remove large twigs.
4. Water is passed through fine sand to remove small particles.
In which order are the processes carried out?
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When solid S is heated strongly, it forms gas G. G turns limewater cloudy. What are S and G and which type of reaction does S undergo? [Table_1]
559
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The element sulfur is found in a number of different minerals.
Which mineral contains the greatest percentage by mass of sulfur?
548
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533
Which structure represents a molecule of ethanol?
513
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550
Petroleum is separated into fractions by fractional distillation.
Separation occurs in a fractionating column.
Some properties of three of these fractions are shown.
[Table_1: Fraction table with boiling point range and number of carbon atoms in the molecules]
Which statement is correct?
576
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582
The flow chart shows the preparation of ethanol and some important chemistry of ethanol.
What are X, Y and Z?
590
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539
The structure of propane is shown.
Which statement about the atoms and the bonding in propane is correct?
506
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559
The structure of a compound X is shown.
X is in the same homologous series as ethanoic acid.
Which row describes some of the properties of an aqueous solution of X?
[Table_1]
528
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556
