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Copper(II) sulfate crystals are separated from sand using the four processeslisted below.In which order are these processes used? 1st filtering 2nd dissolving 3rd crystallising 4th evaporating , 1st filtering 2nd di
A drop of liquid bromine is placed in the bottom of a gas jar. Brown fumes of bromine vapour slowly spread through the covered gas jar.Why does this happen? Bromine vapour is less dense than air., Bromine molecules and the molecules in air are always movin
What is the mass of oxygen contained in 72 g of pure water? [Relative atomic masses: H = 1; O = 16] 16 g , 32 g , 64 g , 70 g
A student tested a solution by adding aqueous sodium hydroxide. A precipitate was not seen because the reagent was added too quickly.What could not have been present in the solution? Al 3+, Ca2+, NH4+, Zn2+
Which molecule has the largest number of electrons involved in covalent bonds? C2H4 , CO2, CH3OH , N2
In which of the following is there a lattice of positive ions in a ‘sea of electrons’? liquid potassium chloride, sand, solid graphite, solid magnesium
Which statement about both chlorine atoms and chloride ions is correct? They are chemically identical., They are isotopes of chlorine., They have the same number of proton
Element X has the electronic structure 2,8,5. Element Y has the electronic structure 2,8,7. What is the likely formula of a compound containing only X and Y? XY3 , X2Y3 , X3Y , X3Y2
A covalent bond is formed by electron sharing between metals and non-metals., electron sharing between non-metals., electron tra
The equation for the reaction between calcium carbonate and hydrochloric acid is shown.CaCO3(s) + 2HCl (aq) ? CaCl 2(aq) + H2O(l) + CO2(g) How many moles of calcium carbonate will give 24 cm3 of carbon dioxide when reacted with an excess of the acid? 1 mol, 0.1 mol, 0.01 mol, 0.001 mol
The empirical formula of a liquid compound is C2H4O. To find the empirical formula, it is necessary to know the density of the compound., percentage composition of the compound., relative molecular mass of the c
in the reaction between zinc and hydrochloric acid. 1 increase in concentration of the acid 2 increase in particle size of the zinc 3 increase in pressure on the system 4 increase in temperature of the system Which pair of changes will increase the rate of reaction? 1 and 2, 1 and 4 , 2 and 3 , 3 and 4
The equation shows what happens in a redox reaction between iron(II) chloride and chlorine gas. 2FeCl 2 + Cl 2 ? 2FeCl 3 Which equation describes the reduction process in this reaction? 2Cl – ? Cl 2 + 2e–, Cl 2 + 2e– ? 2Cl –, Fe2+ ? Fe3+ + e–, Fe3+ + e– ? Fe2+
Which acid and base react together to produce an insoluble salt? hydrochloric acid and sodium hydroxide, nitric acid and calcium oxide, sulfuric acid and barium hy
Carbon and silicon are both in Group IV of the Periodic Table. Which statement is correct for both carbon dioxide and silicon dioxide? They are acidic oxides., They are readily soluble in water., They contain ionic bonds., They have
Which calcium compound does not increase the pH of acidic soils? calcium carbonate, calcium hydroxide, calcium oxide, calcium sulfate
Which deduction about the element astatine, At, can be made from its position in Group VII? It forms covalent compounds with sodium., It is a gas., It is displaced from aqueous potassium ast
Which pair of properties are both correct for a typical transition element? forms coloured compounds soluble in water, high density has variable oxidation states, lo
What happens when zinc foil is placed in an aqueous solution of copper(II) sulfate? Copper(II) ions are oxidised., There is no reaction., Zinc atoms are oxidised., Zinc sulfate is pr
Which element can only be extracted from its ore using electrolysis? calcium, copper, lead, silver
Scrap iron is often recycled. Which reason for recycling is not correct? It reduces the amount of pollution at the site of the ore extraction., It reduces the amount of wast
Aluminium is higher than copper in the reactivity series so the following displacement reaction should be feasible. 2Al (s) + 3CuSO4(aq) ? Al 2(SO4)3(aq) + 3Cu(s) The reaction does not take place at room temperature. What is the reason for this? Aluminium has an inert coating all over it., The compound aluminium sulfate does not exist., The re
The gases coming from a car’s exhaust contain oxides of nitrogen. How are these oxides formed? Nitrogen reacts with carbon dioxide., Nitrogen reacts with carbon monoxide., Nitrogen reacts with o
When a volcano erupts, which gas is produced in significant amounts? carbon monoxide, chlorofluorocarbons, methane, sulfur dioxide
Which statement about ethanoic acid is correct? It contains three carbon atoms per molecule., It contains five hydrogen atoms per molecule., It is
Which bond is present in both nylon and Terylene? C – O , C = O , N – C , N – H
Compounds X and Y are both alkanes. Compound X has a higher boiling point than compound Y. What could be the formulae of compounds X and Y? C8H16 C9H18, C8H18 C9H20, C9H18 C8H16, C9H20 C8H18
With which substance will ethene react to form more than one product? bromine, hydrogen, oxygen, steam
When a compound X is reacted with sodium carbonate, carbon dioxide gas is evolved. What could be the formula of compound X? C2H5CO2CH3, C3H7CO2H , CH3CO2C2H5 , C4H9OH