Question 1The separation of oil and water with different boiling points can best be achieved byA.fractional distillation B.decantation C.evaporation D.using a separating funnel Objective Show full explanation
Question 2Calculate the minimum volume of oxygen that is required for the complete combustion of a mixture of 20cm of Co and 25cm of hydrogen. A.45cm B.22.5cm C.20cm D.10cm Objective Show full explanation
Question 3An increase in temperature causes an increase in the pressure of a gas because there is an increase in the A.average velocity of the gas molecules B.number of collisions between the gas molecules C.density of the gas molecules D.free mean path between each molecule and the other.Objective Show full explanation
Question 4A liquid begins to boil when A.its vapour pressure is equal to the vapour pressure of its solid at a given temperature B.molecules start escaping from the surface C.Its vapour pressure equals the atmospheric pressure D.its volume is slightly increased Objective Show full explanation
Question 5If the relative rate of diffusion of a gas is 0.25 and that of CI, under the same conditions is 0.20, calculate the relative molecular mass of the gas A.22.7 B.45.4 C.68.1 D.90.8 Objective Show full explanation
Question 6The following molecules contain hydrogen bonding EXCEPT A.ammonia B.ethanoic acid C.hydrogen fluoride D.water Objective Show full explanation
Question 7If 20cm3 of distilled water is added to 80cm3 of 0.50mol/dm3 HCI solution, the new concentration of the acid is A.0.10 mol/dm3B.0.20 mol/dm3C.0.40 mol/dm3D.2.00 mol/dm3Objective Show full explanation
Question 8What is H2O2 acting as in the equation? H2O2 + 2H+ + 2Fe2+ + 2Fe2+. A.oxidizing agent B.reducing agent C.an acid D.a base Objective Show full explanation