Chemistry Test Flashcards
Which 2 substances are used to sterilise water
Chlorine and ozone
Which 2 methods show the presence of dissolved solids in the sample of water?
Evaporate all water from sample and measure the samples boiling point
Plan an investigation
1weigh a dry watch glass and record
2set up a tripod gauze and Bunsen burner
3fill a beaker w 100cm3 water
4fill a watch glass with 4cm3 of drinking water
5wait until water evaporates and weigh the watch glass again
Why is desalination only used when there is nothing else?
Requires a lot of energy so it is a lot of money
Complete table for expected results if pure water
7,0
What mass of dissolved solids is present in the sample of tap water?
0.05
What mistake did the students make?
They didn’t fully put the thermometer in the water
2 main steps and reasons to treat lake water
Filtration, removes any solids, sterilisation, removes bacteria
Use the table for knowledge about lca and evaluate paper and polystyrene cups
- Evaluate extraction of raw materials. Crude oil is non renewable and wood releases co2
2evsluate weight, paper cups are heavier to transport, using more energy
3evaluate the usage before burning, both are single use but paper cups use more energy
4evalute what happens after the disposal. Paper cups cannot be recycled unlike polystyrene and polystyrene is not biodegradable unlike paper takes up landfill, contributes to climate change and global warming
How are copper compounds extracted by phytomining
Plant accumulates high concentrations of copper and then is burnt. The ashes contain copper compounds and displacement reaction or electrolysis take place
3 reasons why we should use recycled copper instead of ores
1copper ores are finite
2less energy is used helping environment
3damages ecosystems
