C1 - Exam Mistakes Flashcards
Compounds formed when non-metals react with metals consist of particles called…
Ions
Explain why fluorine and chlorine are in the same group in the periodic table. Explain using electronic structures. 2 marks
Electronic structure of fluorine is 2,7 and chlorine is 2,8,7
So they are in the same group because the have the same number of electrons in their outer shell
Compounds formed when only non-metals react consist of particles called…
Molecules
Why are there many theories to how life formed on Earth?
Not enough evidence or proof
Life on Earth started billions of years ago
What is the problem with cast iron?
Cast iron is brittle
State one property that makes aluminium more suitable than copper for overhead cables
Aluminum has a low density
Why are vegetable oils important in food?
Provide energy
Explain how emulsifier molecules are able to make an emulation. 4 marks
Molecule has a hydrophillic end which is attracted to water
Molecule has hydrophobic end which is attracted to oil
So forms a stable suspension of droplets of oil in water or vice versa
Hydrophilic is the head of the molecule and hydrophobic is tail
How is the solid waste yeast removed after fermentation?
It is filtered out
How is the ethanol obtained from the solution after fermentation?
Distillation
Give 3 advantages of using biodiesel instead of petroleum diesel
Produces less carbon dioxide (less global warming)
Produces no sulphur dioxide (no acid rain)
Conserves the limited amount of petroleum diesel because biodiesel is renewable
Give 3 disadvantages of using biodiesel instead of petroleum diesel
Destruction of habitats
More nitrogen oxides released
Uses crops that could be used for food
Describe how continental drift happens. 5 marks
Because the Earth’s crust
Is divided into tectonic plates
The heat released from radioactive processes
Causes convection currents
In the mantle that move the tectonic plates
When air is distilled, why is carbon dioxide removed before the gases are cooled to -200C?
It forms a solid / freezes
Describe the conditions in the cracking reactor
Vapours of hydro carbon passed over aluminum oxide catalyst
Hydro carbon mixed with steam at high temperatures
Why mustn’t air enter the cracking reactor?
Oxygen could react with hydrocarbons
How does polymerisation happen?
Many monomers
Form long chain molecules which are polymers
Give 3 reasons that copper is extracted from ores containing a very low amount of copper in them
Copper is running out
Copper metal is in demand
Now economical to extract copper from low-grade ores
What type of reaction releases energy from a fuel?
Exothermic
What is locked up carbon dioxide? 2 marks
Carbon dioxide from the air and Earth’s early atmosphere
Formed sedimentary rocks or fossil fuels
Describe how the process of fermentation is done
Sugar is dissolved in water
Yeast is added
Fermentation will then take place naturally
How do you cause an emulsifier to make an emulsion and why?
Shake the oil and water mixture
This breaks the oil into tiny droplets
How can changes to limewater be used to measure how long it took for car in dioxide to be produced. 2 marks
They could measure the time since heating started to when limewater turns cloudy
Why does Iceland have volcanoes?
It is on the BOUNDARY between tectonic plates
Why don’t we know exactly when a volcano will erupt?
Scientists can’t measure what is happening below crust
A student said that hardening olive oil will make it healthier. Is this correct and why? 2 marks
No because hydrogen in hydrogenation adds to the in saturated fat
Therefore there will be less unsaturated fat
What are the conditions for the hydration of ethene to make ethanol?
Presence of catalyst
Why does low carbon steel production use oxygen but titanium production use argon? 3 marks
Oxygen is needed to oxidise carbon
Argon atmosphere used because it is unreactive
Oxygen would react with titanium
What effect does having more manufacturing processes for a material have on how good the process is?
More energy needed so the process isn’t as good
Give 3 advantages of extracting crude oil from Canadian oil sands
It is needed because crude oil is running out can’t meet demand
Could improve Canada’s economy
Could provide many jobs for people
Give 3 disadvantages of extracting crude oil from Canadian oil sands
Destruction of habitats
Crude oil is non-renewable
Burning crude oil releases carbon dioxide
Give a disadvantage of recycling materials from a ballpoint pen
Cost of separating materials is high
Give 2 reasons why alloys are used in the ballpoint pen
Harder than pure metals
Corrosion resistant
Give 2 reasons why the carbon dioxide in the atmosphere has decreased over millions of years
Photosynthesis
Carbon dioxide locked up in sedimentary rock
Why do nitrogen oxides form in car engines? 2 marks
Nitrogen and oxygen in air
Hot temperature causes then to react
What is hydration?
Reaction with water (steam)
Suggest 2 reasons why phytomining is used on a certain area of land instead of other methods
Small amount of copper
More economical
Calcium carbonate is heated and the expected final mass is 2.2g. Give 2 reasons and explain why that might not happen. 4 marks
Calcium carbonate contained impurities (less carbon dioxide produced)
Temperature not high enough (calcium carbonate didn’t fully decompose)
Why didn’t scientists in 1915 not accept Wegener’s theory?
Couldn’t explain why the continents moved
