To summarise, during this reaction zinc chloride and hydrogen gas are been formed at the same time as zinc and hydrochloric acid react. Measure the amount of hydrochloric acid used up per minute 3.
Using the reaction between zinc and hydrochloric acid as an example, the following are methods by which you could measure the rate of that reaction. Measure the amount of zinc chloride been formed per minute 4.
A piece of cotton wool is placed in the neck of the flask to allow carbon dioxide gas to escape. Take readings of mass loss over a time interval, e.g. To find the actual rate we plot the loss in mass (grams) against time (seconds) As with the previous experiment, the steepest part of the curve is at the start, hence the fastest part of the reaction is at the start.
Gradually the curve becomes less and less steep as the reaction slows down.
What we observe over time is that gradually the zinc disappears and bubbles of gas appear.
After a few minutes the bubbles of gas form less and less quickly until finally no bubbles appear because all the acid has been used up, some zinc remains.Rate is a measure of how fast or slow something is.In chemistry, we speak of a rate of reaction, this tells us how fast or slow a reaction is.Why do chemists want to know the rate of a reaction?If you are making a product, it is important to know how long the reaction takes to complete, before the product is produced. Hence, these results show that an increase in concentration increases the rate of a reaction. As you can see, the greater the concentration of the acid used in a reaction the steeper the curve and the shorter the reaction time.A catalyst reduces the energy required for the reactants to successfully collide.The result is more collisions become successful, hence the rate of a reaction increases.This is because, as time goes on the volume of the gas evolved does not change.Marble chips and acid are placed in the flask but separated by a piece of card - preventing the reaction from proceeding.