rates of reaction Flashcards
How can reaction speed be increased?
Increasing concentration, temperature, surface area.
Decreasing particle size, and adding a catalyst or enzyme
What is concentration?
How much substance is dissolved in a volume of water
What is dilution?
Adding more water to a solution to decrease concentration
What must electrodes be?
electrical conductors e.g. metals, graphite
What is voltage?
Voltage is the strength of the push of electricity round a circuit
How can you change voltage?
Changing the electrolyte, changing the electrodes, and changing the number of cells in a battery
What is a chemical reaction?
A reaction between 2 or more substances causing a new product to be formed
What is a physical change?
A substance changes state (solid/liquid/gas) without a new product being produced
What is a catalyst?
A substance which speeds up a chemical reaction but isn’t used up in the reaction (e.g. platinum in catalytic converters)
What is an enzyme?
a biological catalyst (e.g. yeast/amylase)
Why does surface area matter?
If there is more surface area, then more particles are exposed to the reactant
What is rate of reaction?
The speed at which a chemical reaction occurs. Some chemical reactions occur instantaneously, whilst others take a long time.
What are signs that a chemical reaction has taken place?
colour change
bubble or gas produced
heat being given off
what happens when temperature inceases?
the rate of reaction increases too
What is an electrolyte?
Electrolytes are substances that have a natural positive or negative electrical charge when dissolved in water
