Compounds in water (5)

What is the difference between algae and cyanobacteria

Algae are dispersed within water, cyanobacteria is on top of water.

Is algae stronger than cyanobacteria?

No, cyanobacteria is stronger because it is on top (adaptation), if N2 is limited in water, it can uptake from the atmosphere.

How do you classify insoluble substances

Non-settling, settling, suspended

What are electrolytes

Dissolved ions (Ca, Mg, Na…)

What are non-electrolytes?

Dissolved non-ionic (O2, CO2,…)

In what forms does nitrogen occur in water?

Nitrites,Nitrates, Ammonia

What is the organic origin of ammonia

decomposition of animal and plant organic nitrogen, sewage and runoff from agriculture.

What is the inorganic origin of ammonia

Nitrogen fertiliser, contamination of surface and groundwater, wastewater from thermal processing of coal

What happens to water when ammonia/ammonium ion is introduced?

increase pH

what is the equilibrium at 20C when ph is bigger than 9.3?

equilibrium is to the left, toxic form of NH3

what is the equilibrium at 20C when ph is smaller than 9.3?

equilibrium is to the right, non toxic form of NH4 ion

NH4, NH3 what is more toxic

NH3 is more toxic

What happens when temperature/pH increases

percentage of dissoved total ammonia increases

What is the volatile form of ammonia

unionised

What is the non-volatile form of ammonia

ionised

Why is the ammonia toxic to aquatic life mainly?

Because of the unionised form of NH3

What are the sources of Nitrite (NO2)

Atmospheric water, industrial waste

Why is nitrite a good indicator of pollution in groundwater?

It is unstable in water, and in groundwater there are low oxygen concentrations

What is the effect of nitrite on fish?

toxicity

What are the sources of nitrate (NO3)

Atmospheric water, Fertilisers

When is the largest concentration of nitrates?

in the winter

How do you reduce nitrate?

nitrites, elementary nitrogen

Source of cyanide?

There is no natural source, industrial waste water