Chemistry 2b Summary Questions Flashcards
What are the four factors that affect the rate of reaction?
1) concentration
2) surface area
3) catalyst
4) temperature
What are the three ways of measuring the rate of reaction?
1) how much it bubbles if it is acid with metals
2) how long it takes for the solution to become cloudy
3) how much gas is released in a given time
How does higher temperature, concentration and surface area increase the frequency of collisions?
Temperature - higher energy so the particles are moving faster, so they collide more
Concentration - there is more particles of the reactants so they are more likely to collide
Surface area - more of the reactants are exposed to each other so more collisions occur on the outside
What is activation energy?
The amount of energy needed to overcome the bonds of the particles.
What is the definition of a catalyst?
A substance that speed up reactions but does not get used up or changed in the reaction.
What is an exothermic reaction and what are 3 examples?
A reaction that transfers energy to the surroundings. Neutralisation, oxidation and combustion are all exothermic.
The reaction to split ammonium chloride into ammonia and hydrogen chloride is endothermic. What is the reverse reaction?
It is exothermic.
What does the pH scale show?
How acid or alkali a substance is.
What type of ions are always present in
a) acids
b) alkalis
a) H+
b) OH-
What is the ion reaction for neutralisation?
H+ + OH- –> H2O
What is the state symbol that means ‘dissolved in water?
(aq).
What metal doesn’t react at all with dilute acids?
Copper.
What type of reaction is “acid + metal oxide” or “acid + metal hydroxide”?
Neutralisation.
What is electrolysis and why can only liquids be electrolysed?
Electrolysis is the separating of substances by passing through with electricity. Liquids can only be electrolysed because they have free ions.
What are two uses of electroplating?
1) decoration: copper can be coated in silver as it is much cheaper
2) conduction: copper conducts electricity well so they are often used in computers
