Calculating and Measuring Chemical Reaction Rates

The video tutorial explains how to calculate the mean rate of a chemical reaction using different methods. It provides examples involving the reaction between magnesium and hydrochloric acid, measuring either the product formed or the reactant used. Another example involves monitoring a reaction by measuring mass change over time. The tutorial emphasizes understanding the rate of reaction through practical experiments and graph analysis.

What is the mean rate of a chemical reaction defined as?

• The time taken for a reaction to start

• The quantity of reactant used divided by the time taken

• The temperature change during the reaction

• The color change observed in the reaction

In the first example, how is the mean rate of reaction calculated?

• By measuring the temperature change

• By measuring the amount of hydrogen gas produced

• By observing the color change

• By calculating the pH change

What is the mean rate of reaction when 22 cubic centimeters of hydrogen is collected in 60 seconds?

• 0.45 cm³/s

• 0.37 cm³/s

• 0.22 cm³/s

• 0.50 cm³/s

In the second example, what is the mean rate of reaction when a magnesium ribbon disappears in 40 seconds?

• 0.050 per second

• 0.075 per second

• 0.100 per second

• 0.025 per second

What does a decreasing gradient on a mass vs. time graph indicate about the reaction rate?

• The reaction rate is decreasing

• The reaction rate is increasing

• The reaction rate is constant

• The reaction has stopped