Change
Rates of Reaction:
The rate of reaction is how fast the reactants to form products.
Quantity of reactant used
The mean rate of reaction =
time
The rate of reaction will vary during an experiment, they start out fast
and get slower.
Chemical reactions occur when the reactants collide together with a
minimum amount of energy – called the activation energy.
As the reaction progresses there are fewer reactants in the same
volume therefore collisions occur less frequency and the reaction slows
down.
The rate at any given point is the gradient.
To obtain the rate at specific points we draw a tangent at that point
and calculate its gradient.
For a chemical reaction to take place particles of the reactants must
collide with enough energy to react. The minimum amount of energy
particles need to react is called the activation energy.
Reaction Rate Graphs:
AMount of Product Formed
Graphs can be drawn to show how the
quantity of reactant used or product
formed changes with time. The slope of
the line represents the rate of reaction.
The steeper the slope, the faster the
reaction.
To calculate the rate of reaction by
drawing a tangent to a graph:
o Select the time at which you want
time
to measure
o With a ruler, draw a tangent to the curve at that point (the
tangent should have the same slope as the graph line at that
point)
o Choose two points a good distance apart on the tangent line and
draw lines until they meet the axis.
o Find the slope using this equation.
change∈ y axis Temperature affect
slope=
change∈x axis on Reaction
Factors Affecting Rates of Reaction:
Rate
Temperature:
Temperature