water Flashcards
Chemical tests to identify the presence of water:
- Cobalt(II) chloride
- Cobalt (II) chloride paper is blue when dry but turns pink in contact with water
- Copper(II) sulfate
- Copper(II) sulfate is white when anhydrous but turns blue in contact with water
Testing water purity:
- If it freezes at exactly 0
- It it boils at exactly 100
Substances that can be found in water:
- Dissolved oxygen
- Metal compounds
- Plastics
- Sewage and harmful microbes
- Nitrates and phosphates from fertilizers
NPK fertilizers consist of:
- Nitrogen (N)
- Phosphorus (P)
- Potassium (K)
- Salts like potassium nitrate (KNO3) and ammonium phosphate (NH4PO4)
why can’t plants use nitrogen in the air?
- because it is found as a diatomic molecule which has an incredibly strong triple bond and they have no way of breaking this bond
- Plants can only use nitrogen when it is found in more reactive compounds like the nitrate ion (NO3ˆ-) or ammonium (NH4ˆ+)
why is the haber process important in food production?
because it breaks the very strong N-to-N triple bond and converts the nitrogen in our air into a form that plants can use, increasing food production
clean dry air consists of
- Clean, dry air: 78% nitrogen, 21% oxygen, 1% others
where do carbon dioxide emissions come from?
burning of fossil fuels
how/when is methane released?
when plant material decomposes, but also from the digestion of food by intensively-farmed animals like cows
source of acid rain
Sulfur dioxide produced when fuels containing sulfur impurities are burned, especially coal
what do catalytic converters do?
they can remove both oxides of nitrogen and carbon monoxide from exhaust gases:
- 2CO + 2NO → 2CO2 + N2