C3.1 Flashcards
What does the rate of reaction measure?
The amount of product formed in a fixed time
When are reactions usually faster?
At the start but they slow down as the reactants are used up
What units are commonly used when measuring the rate of reaction?
g/s and cm^3/s
How can the rate of reaction be worked out on a graph?
The gradient. This can be calculated by construction lines
What is the gradient of a graph
x
What is the limiting reactant?
The reactant not in excess that gets used up by the end of the reactant
What is the amount of product formed in a reaction directly proportional to?
The amount of limiting reactant used
Give an example on how the amount of product formed and the amount of limiting reactant used are directly proportional to eachother
If the amount of limiting reactant used doubles, the amount of product formed doubles too
When do reactions occur?
When particles collide together
What is interpolation?
Making an estimate within a range of results
How does concentration affect the rate of reaction?
As concentration increases the particles become more crowded . This increases the number of collisions between reacting particles
How does temperature affect the rate of reaction?
The particles gain kinetic energy and move around more quickly so collisions are more successful
What does the rate of reaction depend on?
Collision frequency
What is needed for a successful collision?
Each particle must have enough energy to react
How does pressure affect rate of reaction?
It forces particles together, increasing collision frequency
What is extrapolation?
Making an estimate beyond the range of results
What does a steeper line on a rate of reaction graph show?
A faster reaction
What do combustible powders form?
Explosions
What do combustible powders make when they react with oxygen?
Large volumes of carbon dioxide and water vapour
What increases the surface area of an object?
Breaking up a block into smaller pieces
Why do scientists change the mass of reactant from a block form to a powdered one?
A powdered reactant has a much larger surface are than one of a block form
How do powders increase the collision frequency?
Powders can spread throughout a reaction mixture
How comes collisions are not frequent on those of a block form?
Collisions only occur with the particles on the surface. Most of the particles in the block are trapped on the inside so they are not available to react
What’s good about using a catalyst to speed up the rate of reaction?
The catalyst itself is unchanged in the reaction
Why can’t the same catalyst speed up any reaction?
Each catalyst is specific to a particular reaction
What is the largest number shown for each element?
Atomic mass (A1)
What are the 4 steps of finding the relative formula mass?
- Work out the masses inside of the bracket
- Multiply the total by the number outside the bracket
- Work out the remaining number
- Add the totals from Step 2 and Step 3 to find the relative formula mass
What is conservation of mass?
The total mass of the reactants = The total mass of products
What happens to the atoms if they can’t be created or destroyed?
Mass is conserved and the atoms are rearranged into different compounds
What type of equation have the same number and type of atoms on each side of the equation?
The chemical symbol equation
How can predictions be made ?
The symbol equation for a reaction
