Year 9 Science Chemistry Flashcards
How Fast?
What is meant by the rate of reaction?
how fast the reactants are converted into products
Which of the following could you measure to find out the rate of reaction?
The volume of gas produced
How do you know when the reaction between magnesium and hydrochloric acid is complete?
The magnesium is no longer visible because it has all reacted.
Changing the temperature will affect the rate of the reaction between magnesium and hydrochloric acid. This is because
at higher temperatures the particles have more energy and are more likely to collide and react.
What is the independent variable in how changing the temperature of the acid affects the time it takes for the reaction between magnesium and hydrochloric acid to complete.
The temperature of the acid
What is the dependent variable in how changing the temperature of the acid affects the time it takes for the reaction between magnesium and hydrochloric acid to complete.
The time taken for the reaction to complete
In an investigation, the independent variable is temperature of the acid. What would be the most suitable way to vary the temperature of the acid?
Use a water bath which is set to specific temperatures.
What is the mean rate of reaction
volume of gas formed divided by the time taken
Two investigations are set out, one with more concentration than the other, how would the line of best fit be different for the one with more concentration?
It would have a steeper slope.
Sodium Carbonate (in the correct formulae)
SCO3
Sodium Chloride (in the correct formulae)
S2Cl
What is Collision Theory?
a chemical reaction can only occur between particles when they collide (hit each other)
What can the rate of reaction depend on?
Temperature, Concentration, Particle Size and Catalysts
What will speed up a chemical reaction?
Increasing temperature, Increasing the concentration and adding a catalyst.
What will not speed up a chemical reaction?
Increasing the particle sizes.
What’s the proper name for the Triangle Beaker?
A conical flask
What’s the proper name for a tube with measurements on it?
A measuring cylinder
What is better, Marbled Chips or Marbled Powder ( for a faster reaction)
The marbled powder because it had a larger surface area, giving more opportunities for collision to occur. With the collisions occurring more frequently and more room to travel across, it has been confirmed to be a faster rate of reaction.
What is the formula for rate of reaction?
change in concentration/change in time
What is a catalyst and how are they used?
A catalyst is a substance that can increase the rate of reaction without using itself up.
What can catalysts provide?
Catalysts provide an alternative pathway with a lower Activation Energy.
What does decreasing the activation energy mean?
It means that more particles will have sufficient energy to overcome the energy barrier and react.
What happens during a reaction?
The energy rises to a maximum, then falls.
What is activation energy?
the minimum energy required to cause a process (such as a chemical reaction) to occur.
What is needed to overcome the activation energy?
At least the minimum amount of energy is required. Only reactants with energy equal to, or greater than, this value will react.
If there is a higher concentration what is going to happen?
More Collisions
If there is a lower concentration what is going to happen?
Less Collisions
More frequent collisions come from…
- an increased particle speed
- more particles present
How is
- an increased particle speed
and
- more particles present
achieved?
- A higher temperature
- A higher amount of mass
More successful collisions come from…
- particles with more energy
- a lower activation energy
How is
- particles with more energy
- a lower activation energy
achieved?
- A higher Temperature
- A use of a catalyst
What is a control variable?
A variable that is kept the same during a scientific experiment
What is a dependent variable?
A variable that changes as a result of the independent variable manipulation in experiments.
What is an independent variable?
A variable you manipulate, control, or vary in an experimental study to explore its effects
How do you use a tangent?
A tangent must first be drawn to the curve. Two lines should then be drawn down from two points along the tangent to the x-axis
When are reactions at their fastest?
A reaction is at their fastest at the start because there is the most reactant particles so there is a high frequency of successful collisions
