Using resources Flashcards
What are 4 examples we use the earths resources?
Warmth
Shelter
Food
Transport
How does chemistry plays an important role in how we use resources?
Artificial fertilisers allows us to grow more food with the land available.
Allows us to provide water which is safe to drink
PHTOMINING AND BIOLEACHING help us to extract metals more efficiently
What is potable water?
Water that is safe to drink
What is one key idea about potable water?
Potable water is not the same as pure water.
What does pure water contain and it PH?
NOTHING!
Not even dissolved solids such as salt.
PH 7 (it’s neutral)
What does potable water contain and it PH?
Often contains dissolved solids and PH may not be 7
What are the 2 parts of “Required practical 8: Water” ?
-To analyse a sample of water for purity
-To purify a sample of water by distillation
What is the process of “Required practical 8: Water (analyse a sample of water by purity) “?
- First we check the PH of the water. Pure water has a PH of 7. We an check this by placing small amounts of water onto a piece of universal indicator paper. If green the PH is 7
- If the PH is not 7 then the sample contains dissolved acid or alkali and therefore is not pure
- If the PH is 7 then the water still not may be pure. It may still contain dissolved solids so now we need to test for those.
- We now need to test for those dissolved solids by first balancing the weight of an empty evaporating basin. We need to record the mass
- We fill the evaporating basin with our water sample and place the basin on a tripod or gauze
- We know use a Bunsen burner until it has all evaporated
- We allow the evaporating basin to cool and weight it again. IF THE WATER SAMPLE CONTAINS ANY DISSOLVED SOLIDS THEN THE MASS OF THE EVAPORATING BASIN WILL HAVE INCREASED (Because the water will have evaporated but the dissolved solids will have formed crystals)
HOWEVER EVEN IF THE MASS OF THE BASIN DID NOT INCREASE THEN THE WATER MAY STILL NOT BE PURE. BECAUSE OF DISSOLVED GASES
How are these resources produced?
Agriculture
What is the process of “Required practical 8: Water (purify water by distillations) “?
- This is our apparatus. A comical flask containing our WS (Water sample) which is on a tripod or gauze above a Bunsen burner. On top of the conical flask is a delivery tube that is pointed into a test tube. The test tube is sitting in a beaker containing ice and water.
2.We gently heat the WS using the Bunsen burner (we want the WS to boil gently) At this point the water will evaporate and form water vapour (steam) that travels along the collecting tube into the COLD test tube to condense back to liquid water (distilled water)
What does distilled water contain and PH?
No dissolved solids
PH 7
TRUE OR FALSE.
Distilled water = pure water
TRUE
What does drinking water have to have to be able to be drunken?
-Low levels of dissolved salts like sodium chloride
-low levels of microbe such as bacteria
What doe scientists call water that is safe to drink?
Potable water.
How is rain water a potable water?
Contains low levels of dissolved substances
Where is rain water collected?
In the ground in aquifers
lakes
rivers
reservoirs
How do we produce potable water?
- Choose a good source of fresh water e.g river
- We pass water through filter beds that remove leaves and suspended particles
- The water is then sterilised to kill microbes. We use chloring to sterilise the potable water in the UK
HOWEVER IN SOME PARTS OF THE WORLD OZONE OR ULTRAVIOLET LIGHT IS USED
Why in many places is fresh water scarce?
Some countries, the only available water may be too salty to drink e.g sea water
Why is sea water not able to be drunken and how potable water be produced from it?
-High levels of dissolved minerals
DESALINATION
What does desalination do?
Desalination reduces the levels of dissolved minerals down to an acceptable level for potable water
What are the ways of carrying out desalination and what are the issues?
-Use distillation
- Reverse osmosis (pass water through membranes)
-BOTH PROCESSES REQUIRE VERY LARGE AMOUNTS OF ENERGY WHICH MAKES THEM EXPENSIVE
What are the ways water is used?
-Personal hygiene (baths & showers)
-Flushing toilets and washing clothes
-Agriculture
What does sewage and agricultural waste water require?
Sewage and agricultural waste water require removal of organic matter and harmful microbes.
What does industrial waste water may require?
Industrial waste water may require removal of organic matter and harmful chemicals.