2018 paper 1 Flashcards
When making pure, dry crystals when should you take the solution of the Bunsen burner and leave to dry called
Point of crystallisation
Evaluate the use of hydrogen fuel cells compared with rechargeable lithium - ion battery’s to power cars
Time taken for hydrogen fuel cell to recharge or refuel is 25 minutes less than the lithium ions battery. A fuel cell only produces water whereas the lithium fuel cell could produce toxic waste chemical upon disposal. The fuel cell also has a greater range before it needs recharging or refuelling - lithium ion batteries will also eventually not be able to recharge so they have a finite life. However, the lithium ion cars do use energy more efficiently. The hydrogen in fuel cells is often made from fossil fuels so it’s not renewable. Charging stations for the lithium ion batteries are also more widely available than hydrogen stations - the cost for recharging is also much cheaper. Hydrogen is expensive to contain as its explosive and difficult to store.
Overall I think lithium ion batteries should be used as they produce no emissions whereas the production of hydrogen can produce CO2 which contributed to global warming.
Describe a method used to place copper, iron, magnesium and zinc in order of their reactivity with copper sulphate
Control variables: concentration and volume of copper sulphate solution.
Pour 20cm cubed copper sulphate solution in to 4 conical flasks
Place one metal in the 4 conical flasks
Measure temperature change
Compare results and rank. The one with the highest temperature change is most reactive
Explain why an acid can be described as both a strong acid and dilute acid
It can be a strong acid if it completely ionises in aqueous solutions
It can also be a weak acid if it contains a small amount of acid per unit volume
Why are chlorine and carbon monoxide dangerous
They are toxic
What happens to chlorine in water
It dissolves / reacts with water
Why should a volumetric pipette be used in titrations
It accurately measures a fixed volume
Why should a burette be used in titrations
It can measure a variable volume drop by drop
How to get from cm cubed to dm cubed
Divide by 1000
Formula for concentration
Moles / mass
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Volume
