Chapter 8 Flashcards
What does the rate of reaction mean?
The measure of how quick a reaction was.
How can the rate of reaction be measured?
Measured by workout out how much of one of the products has been made in a given time. Or how much of a reaction has bee used up in a given time.
In the magnesium ribbon experiment, how do you measure the rate of reaction?
The easiest way to measure the rate is to measure how quickly the hydrogen gas is produced.
By measuring the volume of gas produced in a period of time.
Explain how would you carry out the magnesium ribbon experiment to measure the rate of reaction.
Draw a diagram aswell.
Attach a syringe to the top of a flask so that no hydrogen can escape, use the scale on the syringe to measure the volume of gas produced at different times during the reaction.
PG 272
draw a graph of the results in pg 273’s rate of reaction experiment
pg 273
What does anomalous mean in a graph?
anomalous are the marked cross or dot that is not aligned with the order of the results.
How to measure the rate of reaction of calcium carbonate and dilute hydrochloric acid using a weight scale?
As carbon dioxide gas is lost from the flask, the mass of the flask decreases.
Measuring the mass every 30 seconds and you will find out that the mass decreases quickly at first, but as it continues, the mass decreases more and more slowly.
What is normal during the rate of reaction?
At the start of the reaction alot of bubbles were produced. Eventually, fewer bubbles were produced. Eventually, no more bubbles were produced.
This shows that the reaction started quickly, then slowed, and eventually stopped.
How to tell how fast the rate of reaction is in a graph according to the slope or gradient of the line.
The steeper the slope, the faster the reaction.
In the graph in pg 274, describe what happens according to the slope /line
or
Describe what happens to a reaction in graphs
The line is steepest at the start of the reaction. This when the reaction is fastest. As the slope of the line becomes less steep, the reaction is becoming slower.
When the line levels out, it shows that no more carbon dioxide is being lost. Which means the reaction has ended.
The longer the reaction, the slower the rate of reaction
Explain how you would measure the rate of reaction between calcium carbonate and hydrochloric acid.
(Experiment Question)
Hypothesis: The rate of the reaction will be faster when the amount of calcium carbonate or the concentration of hydrochloric acid is increased, as there will be more particles present for collisions, leading to more successful reactions.
Apparatus: 2 Measuring cylinders, conical flask, bung, delivery tube, thistle funnel, water basin, stop watch
Materials: 1M hydrochloric acid, calcium carbonate
Method:
1.Set up the apparatus (pg277)
2.Weigh out about 2g of calcium carbonate
3. Measure 50mL of hydrochloric acid using a measuring cylinder.
4. Place the calcium carbonate into the conical flask
5.Eusure that the measuring cylinder and the delivery tube is connected properly
6.Measure the volume of water
7.Add hydrochloric acid to the flask through the thistle funnel and start the stopwatch immediately
8.Record the volume of gas produced every 30 seconds for 2 minutes
9.Repeat the experiment with different amount of calcium carbonate
what is the word equation for hydrochloric acid and calcium carbonate?
hydrochloric acid + calcium carbonate -> calcium chloride + water + carbon dioxide
how do I improve the reliability of my science experiment results?
ensure consistent procedures, control extraneous variables, repeat measurements, and evaluate results.
what is the chemical equation for hydrochloric acid and calcium carbonate?
CaCO3 + 2HCl → CaCl2 + CO2 + H2O
how do I improve the accuracy of my science experiment results?
maintain equipment, use tools within their appropriate ranges, record significant figures correctly, and take multiple measurements.
What is needed for a chemical reaction to take place?
The particles of the reactants involved have to collide with one another with enough energy to react together
Why do the rate of reaction change?
At the start of the reaction, alot of particles have not reacted.This means that alot of carbon dioxide is produced in the first 30-second period.
As particles react, the number of particles that have not reacted gets lower and lower. The chance of two unreacted particles colliding with each other decreases. This means that less carbon dioxide is formed in the later 30-second periods, therefore slower.
Eventually, all particles have reacted and there are no more collisions that result in the production of carbon dioxide gas. The reaction is finished.
When you put magnesium ribbon in a Bunsen flame, how does it react?
it reacts very quickly and burns with a bright white flame to form magnesium oxide.
What happens if you place a large block of magnesium in the Bunsen flame?
it does not burn
When you place magnesium ribbon in a Bunsen flame
When you place magnesium powder in the Bunsen flame
Which burns the fastest?
Magnesium powder in the Bunsen flame burns much faster than the ribbon.
Magnesium ribbon in a bunsen flame reacts very quickly
large block of magnesium of the same mass in the Bunsen flame does not burn
magnesium powder in the Bunsen flame burns much faster than the ribbon
Explain why does this happen.
Only magnesium atoms on the surface can make contact with the oxygen and react with it, in the block of magnesium, most of the atoms are inside the block and away from the oxygen.
In magnesium ribbon, more of the atoms are on the surface and react. Magnesium ribbon has a larger total surface area than the block of same mass.
Mass of magnesium powder of the same mass has an even larger total surface area because it has most atoms available to react, the reaction is quicker.
Small pieces of solids always react faster than larger pieces.
Is this true?
Yes
Each time we cut a solid into smaller pieces, what happens?
We increase the total surface area.
Slices of bread vs a loaf of bread, which one has more total surface area?
Slices of bread
