Rates of Reaction

Rates of Reaction

Chemistry for Grade 8

Open Ended

What is Rate of Reaction?

Rates of Reaction

• The rate of reaction is simply the speed at which a reaction takes place.

• The units of the rate of reaction: g s^-1 or cm³ / dm³ s^-1, which can then be converted into mol dm³ s^-1.

Measuring the Rates of Reaction

• Working out how much of one of the products has been made in a given time, or how much of a reactant is used up in a given time.

• EXAMPLE: When you add a piece of calcium carbonate to hydrochloric acid, carbon dioxide gas is given off.

Measuring the rate of reaction by finding the loss in mass

• The rate changes as the reaction proceeds

• Example: Reaction between calcium carbonate and hydrochloric acid

• Lots of bubbles of carbon dioxide gas are given off at the start of the reaction

• As the reaction continues, fewer and fewer bubbles are produced

• This shows that the reaction has slowed down

Open Ended

Write the word equation for the reaction of calcium carbonate with hydrochlorid acid!

The word equation for the reaction of calcium carbonate with hydrochloric acid

The easiest ways is to measure how quickly the hydrogen gas is produced:

• Measure the volume of gas produced in a particular length of time.

• To collect the gas you can attach a syringe to the top of the flask so that no hydrogen can escape.

• Use the scale on syringe to measure the volume of gas produced at different times during the reaction.

The table shows results obtaining using this apparatus

The graph of the results is plotted

it is easier to see the pattern that they make.

Anomalous Result

If the results doesn't fit (correspond with) the pattern.

Open Ended

Why these results can be anomalous?

Multiple Select

Give a checklist, what are the factors that affect the reaction rate?

• surface are

• temperature

• pressure

• concetration

• catalysts