6.2. Rate of reaction
A subsection of Chemistry, 0620, through 6. Chemical reactions
Listing 10 of 319 questions
When barium carbonate is added to dilute hydrochloric acid, carbon dioxide gas is formed. A student carried out an experiment to measure the volume of gas formed as a reaction proceeds. The student added a small mass of powdered barium carbonate to an excess of 0.1 mol / dm3 hydrochloric acid. A graph of the results was drawn. The graph is shown. volume of gas / cm3 time / s Name the two pieces of apparatus needed to take the measurements shown on the graph. On the axes below, sketch a graph to show how the rate of reaction changes as the reaction proceeds. Assume the initial rate of reaction is represented by the point at X. time / s rate of reaction X The total volume of gas collected was 180 cm3 at room temperature and pressure. Calculate the mass, in grams, of barium carbonate used. BaCO3 + 2HCl BaCl 2 + H2O + CO2 mass of barium carbonate = g The original graph has been drawn again. On the grid, draw the graph expected if the same mass of barium carbonate is added as large lumps instead of as a powder. All other conditions are the same as in the original experiment. Explain why your graph is different from the original graph. volume of gas / cm3 time / s The original graph has been drawn again. On the grid, draw the graph expected if the concentration of dilute hydrochloric acid is changed from 0.1 mol / dm3 to 0.2 mol / dm3. All other conditions are the same as in the original experiment. Explain, in terms of particles, why your graph is different from the original graph. volume of gas / cm3 time / s The experiment is changed and the mass of powdered barium carbonate is doubled. All other conditions are the same as in the original experiment. The acid is still in excess. Deduce the volume of gas formed at room temperature and pressure, in cm3, in this experiment. volume of gas = cm3
0620_s17_qp_41
THEORY
2017
Paper 4, Variant 1
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The apparatus shown is used to investigate the rate of reaction between calciumcarbonate and hydrochloricacid at 30 °C. water hydrochloric acid A calcium carbonate Name the piece of apparatus labelled A in the diagram. Describe how this apparatus can be used to find the rate of reaction. The experiment is repeated at 20 °C. All other conditions are kept the same. How does the decrease in temperature affect the rate of reaction? The experiment is repeated using the same mass of different size pieces of calciumcarbonate. All other conditions are kept the same. The sizes of the pieces of calciumcarbonate are: ● ● large pieces ● ● small pieces ● ● powder Complete the table by writing the sizes of the pieces in the first column. size of the pieces of calcium carbonate initial rate of reaction in cm3 gas / s  Give the names of the three products formed when calcium carbonate reacts with hydrochloricacid.  
0620_s18_qp_33
THEORY
2018
Paper 3, Variant 3
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319