Rates of Reaction Flashcards
What’s the equation for measuring the rate of reaction?
Time
In which 3 ways can you measure the rate of a reaction?
Precipitation
Change in Mass (usually bc gas is given off)
Volume of Gas Given Off
How do you measure the rate of reaction using the reaction’s precipitation? Example = Limewater test.
This is when the product of a reaction is a solid precipitate, which clouds the solution.
Observe a mark through the solution and measure how long it takes for the mark to disappear.
The quicker the mark disappears, the quicker the rate of reaction.
This type of reaction only works when the solution you’re using is clear at the beginning of the reaction.
The result is very subjective, different people may think that the mark disappears a few seconds earlier or later than someone else.
What’s the problem with using precipitation to measure the rate of reaction?
It’s very subjective. Some people may think the mark disappears before others.
How do you measure the rate of reaction using the change in mass?
Measuring the speed of reaction that produces a gas can be carried out on a mass balance.
Because the mass of the gas disappears, as a gas, the change in mass is easily measured on a scale.
The quicker the reading on the balance drops, the quicker the rate of reaction.
Rate of reaction graphs can be easily plotted using this method.
This is the most accurate of the three methods because a mass balance is very accurate.
What’s a disadvantage of using the change in mass to measure the rate of reaction?
A gas is given off into the room.
How do you measure the rate of reaction using the volume of gas given off?
You use a gas syringe to measure the volume of gas given off, basically.
The more gas given off in one time frame, the quicker the rate of reaction.
A graph of gas volume against time elapsed could be plotted to give a rate of reaction graph.
Gas syringes give volumes to the nearest millilitre, so they’re pretty accurate.
What’s the danger of using the volume of a gas given off to find the rate of reaction?
If a reaction is too vigorous, the gas given off could blow off the end of the gas syringe.
