Experiment on How Increasing Reactant Concentration Affects Reaction Rate

The video tutorial explores an experiment to investigate how increasing the concentration of a reactant affects the reaction rate by observing sulfur precipitate formation. The hypothesis, based on collision theory, suggests that the reaction rate is proportional to the concentration of hydrochloric acid. The experiment involves mixing sodium thiosulfate and hydrochloric acid, observing the cloudiness due to sulfur precipitate, and measuring the time taken for the cross to disappear. The results, plotted on a scatter graph, show a linear relationship, confirming the hypothesis.

What is the main hypothesis of the experiment regarding the reaction rate?

• The reaction rate is independent of concentration.

• The reaction rate is inversely proportional to concentration.

• The reaction rate is proportional to the concentration of one reactant.

• The reaction rate decreases with increasing concentration.

Which two substances are involved in the chemical reaction used to test the hypothesis?

• Sulfur and sodium chloride

• Sodium chloride and water

• Sodium thiosulfate and hydrochloric acid

• Sulfur dioxide and water

What is the independent variable in the experiment?

• Concentration of hydrochloric acid

• Time taken for sulfur precipitate to form

• Volume of the reaction mixture

• Concentration of sodium thiosulfate

What is the purpose of the cross drawn on the card in the experimental setup?

• To measure the volume of reactants

• To determine the temperature of the reaction

• To calculate the concentration of reactants

• To observe the cloudiness of the mixture

How is the mean rate of reaction calculated in this experiment?

• By multiplying the concentration by time

• By using the formula mean rate = 1/time

• By dividing the concentration by time

• By measuring the volume of sulfur produced

What does the straight line of best fit on the scatter graph indicate about the relationship between reaction rate and acid concentration?

• The reaction rate decreases with concentration.

• The reaction rate is directly proportional to concentration.

• The relationship is non-linear.

• The reaction rate is inversely proportional to concentration.

What conclusion can be drawn from the experiment regarding the rate of reaction?

• The rate of reaction is independent of the concentration of the acid.

• The rate of reaction is inversely proportional to the concentration of the acid.

• The rate of reaction is directly proportional to the concentration of the acid.

• The rate of reaction decreases as the concentration of the acid increases.