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Which statement describes a disadvantage of using bioethanol rather than petrol (gasoline) as a fuel for cars? A. The carbon dioxide released when bioethanol burns was recently removed from the atmosphere by the crop B. Bioethanol releases less energy per…
Which statement best describes an environmental consequence of using fossil fuels? A. The carbon dioxide released is completely absorbed by the oceans, so its concentration in the atmosphere does not change. B. Coal has a higher hydrogen to carbon ratio than…
Sucrose, C12H22O11, is hydrolysed with excess water and the glucose formed is then fermented. C12H22O11(aq) + H2O(l) → 2 C6H12O6(aq) C6H12O6(aq) → 2 C2H5OH(aq) + 2 CO2(g) Mr of C12H22O11 = 342.34 Mr of…
Equal volumes of the gases Q2 and R2 are mixed in a sealed container and react until one of them is used up, forming the gas QR2. The volume of QR2 formed, measured under the same conditions, is 50 cm3.…
Equal volumes of nitrogen and hydrogen are mixed and react according to the equation below. The volumes of the two reactants are measured at intervals. N2(g) + 3 H2(g) → 2 NH3(g) Which graph shows how the volumes of the two reactants change with time? A.…
What volume of hydrogen, in cm3, is produced at STP when 0.810 g of aluminium reacts with an excess of hydrochloric acid? 2 Al(s) + 6 HCl(aq) → 2 AlCl3(aq) + 3 H2(g) Molar volume of an ideal gas at STP = 22.7 dm3 mol−1 A. 341 B.…
Which changes would increase the rate of the reaction between nitrogen and hydrogen? N2(g) + 3 H2(g) → 2 NH3(g) I. Lowering the temperature of the gas mixture II. Compressing the gas mixture into a smaller volume at constant temperature III. Adding an…
Nitrogen gas is reacted with excess hydrogen gas to produce ammonia. N2(g) + 3 H2(g) → 2 NH3(g) The reaction of 28.0 g of N2 with excess H2 produces 25.5 g of NH3. What is the percentage yield of NH3? A. 25% B. 50% C. 75% D.…
Which of the following correctly describes the effect of a catalyst on a reaction? A. It increases the frequency of collisions between reactant particles B. It increases the proportion of collisions with energy greater than or equal to the activation energy C.…
The dotted line shows the volume of hydrogen produced when an excess of magnesium ribbon is added to 50 cm3 of 2.0 mol dm−3 hydrochloric acid. Which curve shows the volume of hydrogen produced when the same excess of magnesium ribbon…