Chemistry

Research Question:

Is the West Lake polluted by chemicals?

This will be done by sampling the West Lake water and checking its pH. So, if the water has a pH value of 7 and below its acidic and if the water has a pH value of a 7 and above it will be basic. If the pH value is at 7 then the water is normal. Based on these values, we can then find out, the level of pollutions of west lake. Water in Tay Ho maybe polluted due to the erosion of the constructions near the lake and so, I will react NaCl (aq) with two areas of water of the West Lake. By doing this, I will be able to find the how much Lead is in the lake as NaCl (aq) will react with lead and create solid PbCl (s). So, the more precipitates of PbCl the more Lead are in the water.

I will also use the Chlorine Test Kit to test the amount of Chlorine in the two areas of water of West Lake.

Equipments:

2x 500mL beaker 500g salt (NaCl) Electric balance Stiring Rod Chlorine Test Kit Distilled water

Results:

pH of West Lake water in the first area

8.76

pH of West Lake water in the second area (near water park)

8.78

Therefore the water is basic.

After reacting NaCl (aq), with the West Lake water in the first area there are no precipiates created therefore there are no Lead content in it.

After reacting NaCl (aq) with the West Lake water in the second area there are also no precipitated created therefore there are no Lead Content in it.

Using the Chlorine Testing Kit, this is what I found:

(mg/L) || Combined Chlorine (mg/L) ||
 * || Free Chlorine (mg/L) || Total Chlorine
 * Area 1 || 2.0 || 2.5 || 0.5 ||
 * Area 2 || 2.0 || 2.5 || 0.5 ||

Free Chlorine is also called hypochlorite ion and they come from bleach. So, it can be concluded that the soil that is used for construction has bleach and when it erodes and enter the lake it polluted the lake with hypochlorite ions. When hypochlorite ion mix with other contaminants its call a 'combined chlorine' and total chlorine is the sum of free and combined chlorine is total chlorine.