Chemistry - Chemistry of the environmenet (PART 1)

What are tests for water?

Turns white anhydrous copper (II) sulfate blue and turn blue colbalt (II) chloride pink

How to test for purity of water?

If a liquid is pure water, it will boil at 100 celisus and freeze at 0 celisus

What water is used in the lab?

Distilled water, as tap water contains dissolved substances

Water from natural substance may contain substances like…

dissolved gases from the air, metal compounds, plastics, sewage, harmful microbes, nitrate from fertilisers, phosphates from fertilisers and detergents and minerals.

How does water contain dissolved gases?

Riverwater contains oxgyen and nitrogen and can also contain harmful gases from engines, power stations and factories

How does water contain metal compounds?

From waste water from mines and factories

How does water contain harmful microbes?

From untreated sewage disposed into soil and drained into rivers or wells

What substances found in natural water are benefical

Dissolved oxgyen for aquatic life (depend on oxgyen for life processed) and essential minerals for huamns (our bodies need around 12 elements to function)

What substances found in natural water are harmful?

Toxic metals (number of metals are toxic to humans), plastics (harm fish and other aquatic animals, mistake them for food), microbes from untreated sewage (may contain bacteria that cause chlorea, typhoid and virus that cause hepatitis), nitrates and phosphate (promote eutrophication process)

What are the steps for water treatement?

• Find cleanest source of water

• Remove as many solid particles though processes like filtration, sedimention and flocculation

• Remove as many unwanted dissolved compounds through use of carbon to filter water and removal of substances that cause nasty smells and taste

• Adding something to kill microbes (e.g chlorinatioon)

• Store water safely, ready to pump to taps or tanks

Fertilisers

Any substance added to the soil to make it more fertile

What are the three main nutrients plants need and their uses?

Nitrogen (make chlorophyll), potassium (produce proteins) and phosphrous (helps roots grow).

What is the most important nutrient plants need?

Nitrogen

Synethetic fertilisers

Salts made in factories, many are made of ammonium salts and nitrates

NPK fertiliser

A mixture of salts that provide all three elements plant need (nitrogen, phosphrous and potassium) for improved plant growth

Air definition

Everyday name for the layer of gas around us

Composition of clean dry air at sea level on Earth

Other 1% mainly argon, some carbon dioxide and small amounts of other noble gases

What are fossil fuels?

Coal, petroleum and natural gas (all based on carbon)

Examples of air pollution from fossil fuels

Carbon dioxide, carbon monoxide, particulates, sulfur dioxide, nitrogen oxides and methane

How is carbon dioxide formed?

From complete combustion of fuels that contain carbon (coal gas, petrol, e.g)

What harm does carbon dioxide do?

Occurs naturally, but increased amount lead to increased global warming which leads to climate change

How is carbon monoxide formed?

In the incomplete combustion of fuels that contain carbon when there is a limited supply of air e.g car engines

What harm does carbon monoxide do?

Is a toxic gas and is poisonous even in low concentration, leads to death from lack of oxgyen

How is particulates (tiny solid particles) formed?

Incomplete combustion of fuels that contain carbon, e.g particles of soot from diseal engines

What harm does particulates do??

Increase risk of respiratory problems and cancer

How is sulfur dioxide formed?

Combustion of fossil fuels that contain sulfur compounds, power stations are main source

What harm does sulfur dioxide do?

DIssolves in rain to from acid rain, attacks stonework in buildings and acidifies rivers and lakes which kills aquatic life and also kills trees and insects

How is nitrogen oxides formed?

Form when nitrogen and oxgyen in the air react together inside hot motor engines and furnances

What harm do nitrogen oxides do?

Cause respiratory problems, form acid rain, and from photochemical smog

How is methane (main component of natural gas, fossil fuel) formed?

Decomposition of vegetation and waste fases from digestion in animals

What harm does methane do?

Higher levels of methane lead to increased global warming which leads to climate change