2b Flashcards
what four factors affect the rate of a reaction
- temperature
- concentration
- catalyst
- surface area of solids
what three ways can you measure the rate of a reaction?
- precipitation (where you observe a mark and measure how long it takes before you can’t see the mark because of the clouded solution)
- change in mass (the quicker the reading on the balance drops, the faster the rate of reaction)
- the volume of gas given off (use a gas syringe to measure how much gas is given off and how fast)
what is activation energy?
the minimum amount of energy needed for the particles to react
what is a catalyst?
a substance which speeds up a reaction without being changed or used up
what are the advantages of using catalysts in industrial processes?
- its cheaper
- less energy needed
- never get used up so can be used over and over again
what are the disadvantages of using catalysts in industrial processes?
- expensive to buy
- different reactions need different catalysts so lots of different types are needed
- catalysts can be poisoned by impurities so they stop working
what is an exothermic reaction?
where energy is transferred into the surroundings, usually in the form of heat shown by an increase in temperature
what is an endothermic reaction?
where energy is taken in from the surroundings, usually in the form of heat shown by a decrease in temperature.
what does the pH scale show?
how acidic or alkaline a solution is
what type of ions are always present in acids?
H+
what type of ions are always present in alkalis?
OH-
what is neutralisation?
a reaction between acids and bases
what is the equation for neutralisation?
acid + base = salt + water
what is the equation for reacting a metal with an acid?
acid + metal = salt + hydrogen
what metal doesn’t react with dilute acids?
copper
