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Which statement about all the noble gases is correct ? The number of protons in the atoms equal the number of neutrons, Their atom each have a stable arra
A substance Q conducts electricity both when solid and molten what is Q ? an alloy, a hydrogencarbon, a metal oxide, a salt
Substance X has a melting point higher 500 °C .it is insoluble both in water and in organic solvent .it conduct electricity when both solid and molten what is X : Copper, Mercury, Poly(ethene), Sodium chloride
How many moles per dm3 of gaseous carbon dioxide are three If 4.4 g occupies 500 cm3 ? 0.1 mol/dm3, 0.2 mol/dm3, 2.2 mol/dm3, 8.8 mol/dm3
Which reaction take place during the electrolysis of aqueous copper (II) sulphate with copper electrodes ? CU2++ 2e- ? Cu, CU ?Cu2+ + 2 e-, 4OH- ?2H2O + O2 + 4e- , CU 2+ + 2e- ?Cu, CU ? CU2+ +2e-, 2H+ + 2
The heat-reflecting shields of some space rocket are gold plated, using electrolysis.which electrodes and electrolyte would be used to gold-plate the heat shield ? Carbon , heat shield , gold compound, Gold , heat shield , Copper compound, heat shield ,Carbon ,
The reaction C2H4 + 3O2 ? 2CO2 + 2H2O IS Exothermic because : More bond are broken then are formed , More bond are fromed then broken, The energy needed to break
A colourless gas is passed into each of three different solutions.the result are shown in the tableresult stays colourless orange to green purple to colourless what is the colourless gas ? an acid, an alkali, an oxidising agent , a reduced agent
Chlorine can be manufactured by using the reversible reaction between hydrogen chloride and oxygen 4HCl(g) + O2 ? 2H2O (g) + 2 Cl2(g) ?H is negative A mixture in dynamic equillibium is present at 450 °C which change to mixture will increase the amount of chlorine at equillibium ? adding a catalyst, adding more HCl(g), decreasing the pressure, Increasing the temperature
Which pair of substance produced a precipate when their aqueous solution are mixed ? Sodium chloride and barium nitrate, Sodium nitrate barium and chloride , Sodium nitrate and silver
Which statement about catalysts is correct ? catalysts are used in industry to reduced energy costs, catalysts are used up during a reaction, iro
Element X is a solide at room temperature it need one electron per atom to gain the electronic structure of a noble gas it is the least reactive element its group what is the element X : At, Cs, F, Li
Aluminium is used to make saucepans because of its apparent lack of reactivity which propertyy of aluminium explain its uneactivity ? it has a high electrical conductivity, it has a low density, it has a surface layer of oxide, It has
Alloys are usually harder then the metals expplains the greater hardness of alloys ? Atomic radii, densities, Electrical conductivities, relative atomic masses
Which gas cannot be removed from the exhaust gases of a petrol powered car by its catalytic converter ? Carbon dioxide, Carbon monoxide , hydrcarbon, nitrogen dioxide
Which gas present in pond water decrease in concentration during eutophication ? carbon dioxide, methane, nitrogen, oxygen
Aluminium sulphate can be obtained as shown in the equation 2 Al(OH)3 + 3H2SO4 ? Al2(SO4)3 + 6 H2O HOW MANY MOLES OF SULPHURIC ACID ARE NEED to produced 0.5 mol of aluminium sulphate ? 0.5, 1, 1.5, 3
Which property of the alkanes does not increase relative molecular mass increases ? boiling point, flammability, melting point, Viscosity
What is the structure of the product of the reaction between butene , CH3-CH2-CH=CH2 and bromine , Br2 ? CH2Br-CH2-CH2-CH2Br, CH2Br-CH2-CHBr-CH3, CH3-CHBr-CH2-CH2Br, CH3-CH2-CHBr-CH2Br
Which formula represent a compound that will react with sodium carbonate to give off carbon dioxide ? CH3OH, HCO2CH3, CH3CO2H, CH3CO2H5
IN which of the following are all the compound membranes of the same homologous series ? CH4 C2H6 C3H6, CH4 C2H6 C3H8, CH4 C2H6 C3H10, C3H4 C3H6 C3H8