Periodic Table
What name do we give to group 1 in the periodic table?
Alkali metals
If you had three samples of 10g of marble chips, all reacting with 50ml of HCl, which would react the quickest: powder, small chips, large chips?
powder
What happens to the rate of reaction as you increase temperature?
It increases
Breaking bonds - exo or endothermic?
Endothermic
How many electrons are in the outer shell of a noble gas?
8
Describe the trend in reactivity as you go down group 1 of the periodic table.
The reactivity increases
On a graph showing the rate of a chemical reaction, how can you tell when the reaction has finished?
The line of the graph levels out / becomes horizontal.
What is a catalyst?
A substance that increases the rate of reaction, but does not get used up.
Name one type of reaction that is always exothermic
neutralisation, displacement, combustion
How does concentration affect the rate of a chemical reaction?
Increase concentration = faster rate
Complete this balanced symbol equation:
2K + 2H2O → ___?____ + ____?___
2K + 2H2O → 2KOH + H2
How can you find out if a reaction is endo or exothermic?
Measure the temperature of the surroundings, before and after the reaction.
How does a catalyst increase the rate of a reaction?
It lowers the activation energy
The amount of energy needed to get a reaction started is known as the what?
Activation energy
Why are investigations into exo and endothermic reactions carried out in a polystyrene cup?
To reduce heat transfer to / from the air.
Why do group 1 elements become more reactive as you go down the periodic table?
The outer electron is further away from the nucleus, so is easier to lose.
Describe how to measure the rate of a reaction that produces a gas.
Collect the gas in an upside down measuring cylinder filled with water, OR carry out the experiment on a balance.
How does increased pressure increase the rate of a reaction?
It causes the particles to be more crowded, meaning there are more frequent collisions
What do we call the diagrams that show the energy changes in a chemical reaction?
Reaction profile.
What must happen to particles of different substances before they can react?
Collide, with enough energy
Br2 + 2NaI → 2NaBr + I2
Give the ionic equation for this reaction, ignoring any spectator ions.
Br2 + 2I- → 2Br- + I2
How can the reaction between sodium thiosulfate and hydrochloric acid be used to investigate rates of reaction?
Time how long it takes for the solution to become too cloudy to see a cross through it.
How does increased temperature increase the rate of reaction? (two part answer)
Particles have more energy, so move around more quickly, meaning there are more frequent collisions, AND
the collisions have more energy so are more likely to react.
What do we actually mean by the "energy of a bond"?
The amount of energy needed to break a mole of a particular bond OR the amount of energy released when a mole of a particular bond is formed
Why do group 7 elements become less reactive as you go down the periodic table?
The outer electron shell is further from the nucleus, so the force of attraction on the outer electron, from the nucleus, is less