Questions Corrections 2018 Flashcards
(18 cards)
What colour flame would sodium ions produce
Yellow
Name a metal ion that would produce a green flame
Copper ion
Why is it difficult to identify the metal ions from the colour of the flame
The flame colours are masked
Describe a test to show the presence of sulfate ions in the solution
Add barium chloride
Add hydrochloric acid
White precipitate produced
What name is given to a useful product
Formulation
Suggest two use of methylated spirit
Fuel
Solvent
Describe how ethanol is produced from sugar solution
Fermentation
Add yeast
In anaerobic conditions
What type of substance reacts with methanol to produce methanoic acid
Oxidising agent
The percentages of carbon dioxide and oxygen have changes from Earths early atmosphere to Earths atmosphere today
Explain the processes that led to these changes
Carbon dioxide decreased as volcanic activity released water vapour which condensed to form oceans , carbon dioxide dissolved in oceans and carbonates produced sediments and carbon was locked up in sedimentary rocks
Algae and plants evolved and they absorb carbon dioxide by photosynthesis and release oxygen
Carbon locked up in fossil fuels
Why are scientists not certain about the percentage of each gas in the earths early atmosphere
Occurred 4.6 billion years ago
Polyesters are produced when monomers join together and lose a small molecule
Name the small molecule lost
Water
A mixture of polypropene and wool to make carpets more sustainable than using just polypropene
Suggest why
Polypropene comes from a non renewable source
And wool carpet needs replacing more often
Three reasons why the maximum allowed percentage of carbon monoxide has been decreased for newer cars
Carbon monoxide is toxic
Greater public concern about pollution
Why are unburned hydrocarbons in exhaust flames bad
They cause global dimming
Describe how oxides of nitrogen are produced when petrol is burned in car engines
Nitrogen reacts with oxygen
At a high temperature
Two effects of atmospheric pollution which are reduced by using catalytic converters
Acid rain
Respiratory problems
A higher pressure gives a greater yield and an increased rate of reaction
Explain why
Equilibrium position moves to product side
As fewer particles on the product side
More collisions per unit time
As more gas particles per unit volume
Melamine (a polymer) does not melt when it is heated explain why
Thermosetting polymer
Contains crosslinks between polymer chains
