The formulae for two ions are given.
Which statement is correct?
The formulae for two ions are given.
Which statement is correct?
Which row shows both a property of a gas and the correct explanation for this property?
When measured under the same conditions of temperature and pressure, which gas diffuses at the same rate as nitrogen?
X and Y are both elements, one of which is a non-metal.
1 mole of X is added to 1 mole of Y and they are heated together.
X and Y react completely to form substance Z.
Substance Z cannot be easily separated to form X and Y.
Three statements are given.
Y must be the non-metal.
X and Y formed a compound on heating.
Substance Z has the empirical formula XY.
Which statements are correct?
An ion has an electronic configuration of 2,8,8. It has a 2– charge and a nucleon number (protons + neutrons) of 36. How many neutrons are present in the nucleus of this ion?
The formulae for two ions are given.
Which statement is correct?
Which statement about exothermic and endothermic reactions is correct?
If calcium carbonate is heated in a closed container, it will decompose, forming calcium oxide and carbon dioxide. Calcium oxide and carbon dioxide can recombine to form calcium carbonate.
After some time, a position is reached where calcium carbonate is decomposing, and calcium oxide and carbon dioxide are recombining at the same rate.
What is this position called?
Which formula represents the oxide of element Z in Group II of the Periodic Table?
Element X is in Group I.
Some statements about element X are given.
X is not the least dense element in Group I.
X is more reactive than potassium.
Which element is X?
A student makes three statements about metals and non-metals.
All alloys contain at least one metal.
All metals are good thermal and electrical conductors.
All solid non-metals are malleable.
Which statements are correct?
Which row shows the correct percentage by mass of the element in each compound that improves plant growth?
Which row shows a gas produced in each process?
Which compound is not an alkane, alkene, alcohol or carboxylic acid?
Which equation shows the cracking of decane to produce two different alkenes and at least one other product?
Which statement is correct?
How many moles of oxygen are required for the complete combustion of 2 moles of ethanol?
Two reactions are shown.
Which row is correct?
A section of the structure of a protein is shown.
R O R O R O R O ─N─C─C─N─C─C─N─C─C─N─C─C─ | | | | | | H H H H H H
How many amino acid monomer molecules have been used to make this section of the structure?
Which row is correct?
A mixture of four coloured dyes is analysed by chromatography. The result is shown.
solvent front
baseline
Which change allows the four coloured dyes to be seen separately?
An aqueous solution contains cations of metal X. A precipitate forms when a few drops of aqueous sodium hydroxide are added to the solution. The precipitate dissolves in excess aqueous sodium hydroxide. What is a possible identity of metal X?
aluminiumammoniumzincA
✗B✗C✗✗D✗✗
key
= yes
✗ = no
Which pair of molecules have the same number of electrons in covalent bonds?
Aqueous copper(II) sulfate is electrolysed using copper electrodes.
Which row describes the changes that take place during the electrolysis?
Which row describes one advantage and one disadvantage of using a hydrogen-oxygen fuel cell to power a road vehicle?
Two gases react together to produce a single product.
The rate of the reaction is affected by an increase in pressure. The reaction is catalysed by platinum.
Which row describes one effect on this reaction of increasing pressure and one effect on this reaction of adding platinum?
Which row identifies the treatment and its effect?