Measuring Reaction Rates

Which observation(s) might be used as evidence that a chemical reaction occurred?

• Color change

• Odor change

• change in temperature

• All of the above

Order the letters from highest to lowest rate of reaction.

• A > B > C > D
• A > BC > D (B and C have the same rate)
• A > B > CD (C and D have the same rate)
• D > C > B > A

What is the rate of reaction?

• How fast a reaction is 
• How big a reaction is
• How loud a reaction is
• How much gas a reaction produces

The following equation shows the reaction between calcium carbonate, CaCO₃ and hydrochloric acid, HCl:

CaCO_3(aq) + 2HCl_(aq) → CaCl_2(aq) + CO_{2 (g)­­} + H₂O_(l)

Which of the following is the suitable method to determine the rate of reaction?

• Change in the temperature of the solution with time

• Change in the volume of carbon dioxide gas with time

• Change in the mass of water with time

• Change in the concentration of hydrochloric acid with time

Table 4 shows the total volume of gas evolved at different intervals for the dissociation of hydrogen peroxide.

What is the average rate of reaction in the second minute?

• 14.0 cm³ min^-1

• 16.0 cm³ min^-1

• 18.0 cm³ min^-1

• 28.0 cm³ min^-1

Diagram 4 shows the graph of volume of carbon dioxide gas against time when 5 g of marble chips is added to

50 cm³ of 0.2 mol dm^-3 hydrochloric acid.

At what time the rate of reaction the highest?

• t1

• t2

• t3

• t4

Which acid concentration would react faster with Magnesium?

• 0.1M

• 0.4M

• 1M

• 2M

A liquid X reacts with solid Y to form a gas.
Which two diagrams show suitable methods for investigating the speed of the reaction? 

• 1 and 3
• 1 and 4
• 2 and 3
• 2 and 4

The following equation represents the reaction between calcium carbonate, CaCO₃ and hydrochloric acid, HCl.

CaCO₃ + 2HCl --> CaCl₂ + CO₂ + H₂O

Which changes can be used to determine the rate of reaction?

I : mass of calcium carbonate per unit time

II : Volume of carbon dioxide released per unit time

III : Colour of solution per unit time

IV : Mass of precipitate produced per unit time

• I and II

• I and III

• II and IV

• III and IV

The reaction between zinc, Zn and hydrochloric acid, HCl is represented by the following equation.

Zn + 2HCl --> ZnCl₂ + H₂

A student wants to determine the rate of reaction in a school laboratory. Which of the following methods is the most suitable?

• Determine the change in temperature of the solution with time

• Determine the change in the concentration of zinc chloride with time

• Determine the volume of hydrogen gas given off with time

• Determine the change in the concentration of hydrochloric acid with time