Recall Sem 1: Rate of reaction

A large excess of marble chips is reacted with 25 cm³ of 1.0 mol dm^-3 of hydrochloric acid at 40^oC. How is the result different when the reaction is repeated with 60 cm³ of 0.5 mol dm^-3 hydrochloric acid at 40^oC.

• Faster reaction & more products

• Faster reaction & less products

• Slower reaction & more products

• Slower reaction & less products

Which changes can be used to measure the rates of chemical reactions?

(select all correct answers)

• the decrease in concentration of a reactant solution per unit time.

• the rate of appearance of a product

• the decrease in volume of product gas per unit time

• the increase in volume of product solution per unit time

Why does the rate of gaseous reaction increase when the pressure is increased at a constant temperature?

• higher proportion of particles have energy greater than activation energy.

• The particles have more space in which to move.

• The particles move faster.

• There are more frequent collisions between particles

Which curve was obtained if the rate of reaction was plotted against time for an autocatalytic reaction?

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The Boltzmann distribution curve for a gaseous mixture of ethene and hydrogen is shown. Nickel is an effective catalyst for the reaction that occurs.
How does the diagram appear if the same reaction mixture is at a higher temperature?

• The curve is unchanged.

• The values of both E_a(catalyst) and E_a decrease

• The values of both E_a(catalyst) and E_a increase

• The values of both E_a(catalyst) and E_a remain the same