C8.1 Flashcards
What is meant by the rate of a chemical reaction
What are two ways to measure rates of reaction?
g/s and mol/s
What is another unit that can be used to measure rates of reaction?
s/cm
What does the graph label indicate when the reaction is fastest?
The graph label indicates the point where the reaction rate is at its maximum.
This is typically shown at the steepest part of the graph.
What does the graph label indicate when the reaction is finished?
The graph label indicates the point where the reaction has completed and no further change occurs.
This is shown when the graph levels off.
What does the rate of a chemical reaction indicate?
The rate of a chemical reaction tells you how fast reactants are turned into products.
How can you calculate the rate of a reaction?
You can calculate the rate of a reaction by finding out how quickly the reactants are used up or how quickly the products are made.
What can be plotted to show changes in reactants and products over time?
A graph can be plotted to show how the quantity of product formed or the quantity of reactant used up changes with time.
What does the gradient of a tangent to the curve of the graph represent?
The gradient of a tangent to the curve of this graph at a specific time indicates the rate of the reaction at that time.
What is produced when zinc reacts with hydrochloric acid?
Zinc chloride and hydrogen gas.
Write the chemical equation for the reaction of zinc with hydrochloric acid.
Zn(s) + 2HCl(aq) → ZnCl2(aq) + H2(g)
What does the graph show regarding the reaction?
The graph shows how the volume of hydrogen produced changes with time.
What is the unit of measurement for the volume of gas produced in the graph?
Cubic centimeters (cm³).
What is the unit of measurement for time in the graph?
Minutes.
Explain how to calculate rate of reaction from a graph
Step 1
Draw a tangent to the curve
Make it long
Step 2
Construct a right angled triangle using the tangent as its longest side
Choose 2 points you can easily read the values of for corners of the triangle
Step 3
Calculate gradient of the tangent
Y-value/x-value
What is the chemical reaction equation for calcium carbonate reacting with hydrochloric acid?
CaCO₃ + 2HCl → CaCl₂ + H₂O + CO₂
This reaction produces carbon dioxide, water, and calcium chloride.
What happens to the mass of the reaction mixture as carbon dioxide is produced?
The mass of the reaction mixture decreases
This is due to the release of carbon dioxide gas.
What is the initial rate of the reaction characterized by?
The rate of the reaction is fastest
This is indicated by the steepness of the tangent to the curve on a graph of mass against time.
How does the gradient of the graph change as the reaction progresses?
The gradient decreases
This indicates that the reaction rate becomes slower over time.
What does a gradient of zero indicate in the context of the reaction?
The reaction is finished
At this point, carbon dioxide is no longer being produced.
Fill in the blank: At the start of the reaction, the gradient of the tangent to the curve is very _______.
steep
A steep gradient indicates a fast reaction rate.
True or False: The reaction rate remains constant throughout the entire reaction.
False
The reaction rate slows down as the reaction progresses.
How can you find out the rate of a chemical reaction?
By monitoring the amount of reactants used up over time or measuring the amount of products made over time
This involves measuring changes in concentration, volume, or pressure during the reaction.
What two methods can be used to determine the rate of reaction?
- Monitoring the amount of reactants used up
- Measuring the amount of products made
Both methods require time as a factor for accurate measurement.
