Question

In an experiment, sulfuric acid reacted with different volumes of sodium thiosulfate in water. A yellow precipitate was formed during the reaction. A cross drawn at the base of each flask became gradually invisible due the formation of this yellow precipitate. The time taken for the cross to become invisible was recorded. A partial record of the experiment is shown. Experimental Record Flask Volume of H2SO4 Volume of Sodium Thiosulfate Volume of Water Time 1 5 mL 50 mL 0 mL 19 seconds 2 5 mL 40 mL 10 mL 3 5 mL 30 mL 20 mL 4 5 mL 20 mL 30 mL Based on your knowledge of factors that affect the rates of chemical reactions, predict the trend in the last column of the experimental record. Use complete sentences to explain the trend you predicted. You do not have to determine exact values for time; just describe the trend you would expect (increase or decrease) and why it occurs

Answer 1

Answer:

The column for time decreases steadily

Explanation:

The rate of reaction depends on concentration of species, we also know that concentration decreases when more volume of water is added. Hence the concentration of the solute (thiosulphate) increases with decreasing volume of water.

As the concentration of the thiosulphate increases, reactant particles collide more frequently, the number of effective collisions between reactant particles increases and the rate of reaction increases alongside.

As the rate of reaction increases, the cross takes a shorter time to disappear because the reaction now proceeds faster. This implies that the last column (time) will decrease steadily.