Flashcards in Chapter 2b Deck (38)
What is the formula for rate of a reaction?
Amount of reactant used/ amount of product formed
State the different ways used to measure rates of reaction
Change in mass
Volume of gas given off
Explain collision theory with regards to increasing temperature
When the temperature is increased the particles all moe quicker, if they're moving quicker they're going. To collide more often
Explain collision theory with regards to higher concentration
If a solution is made more concentrated it means there are more particles of he reactant which makes collisions between important particles more likely
Explain collision theory with regards to larger surface area
If one of the reactants is a solid hen breaking it up into smaller pieces will increase the total surface area if the particles have more area to work on there will be more frequent collisions
Define activation energy
The minimum amount of energy needed for the particles to react (reactions only happen if the particles collide with enough energy
What is a catalyst?
A substance that speeds up a reaction without being changed or used up in the reaction
How are catalysts useful in industry?
- because the reaction is quicker it saves money
- allows the reaction to work at lower temperatures which reduces the energy used in a reaction
Can be used over and over again
State some disadvantages of catalysts
Expensive to buy
Different reactions use different catalysts
Catalysts can be 'poisoned' by impurities so they can stop working
Reaction must be kept clean
What happens in exothermic reactions?
Heat is given out to the surroundings they warm up
E.g combustion, hand warmers and self heating cans
What happens in endothermic reactions ?
Heat is taken in by the surroundings, they become cold
E.g thermal decomposition and sports injury packs
What pH do acids have?
What colour do they turn?
What pH do alkalis have?
What pH is neutral?
Describe the properties of an acid
pH less than 7
Form h+ ions in water
Describe the properties of alkalis
A base that dissolves in water
Form OH- ions in water
Acid + base =
H+ + OH-
Acid + base ---->Salt + water
H+ + OH- ----> H2O
What is the state symbol of
a) a solid
b) a liquid
c) a gas
Acid + metal =
Metal salt + hydrogen
What kind of salts would hydrochloride acid produce
What kind off salts would sulfuric acid produce?
Acid + metal oxide=
Salt + water
Acid + metal hydroxide =
Salt + water
Hydrochloric acid + copper oxide=
Copper chloride + water
Nitric acid + potassium hydroxide =
Potassium nitrate + water
What four things does the rate of reaction depend on?
Splitting up using electricity
(If you pass an electric current through an ionic substance that's molten or in a solution it breaks down into the element it's made of)
- it requires a liquid (electrolyte) to conduct electricity
- electrolytes contain free ions which allows electricity
- flow of electrons is needed ( electrons taken away at the positive electrode and given at the negative electrode)