Chemistry

Nguyen Le Huy Seong Hyun Park

=Chemistry Experiment:= Aim: Investigate the buffering capacity of water in Tay Ho compared to the buffering capacity to distilled water.

Test 1: The concept is similar to the investigation done over the field trip. Water with high buffering capacity will be able to resist an increase in acidity in water. Tay Ho is an outside large lake and is often used as a drain for rainwater. In an area that is industrialized and with factories like North Vietnam, it is assumed that the rate of burning coal is quite high, and so acid rain is a possible harmful threat to the water in Tay Ho.

Test 2: Availability of oxygen in water through the assessment of the lake turbidity. The turbidity of a water sample is the measure of the cloudiness of the dissolved liquids in the water. The higher the turbidity, the more light his inhibited from entering deep into the water collumn, therefore oxygen is less readily available for organisms. This will be done by a secchi disk. the secchi disk will be self-prepared.

Test 3: Conduct a qualitative analysis on the water sample using selective precipitation to the best of our available equipment. The availability of H2S might be a problem, however using HCl we can determine the presence of Ag, Hg and Pb ions in the water. The following precipitation agents can be used to determine the presence of several different ions in the water sample: Silver Nitrate + Nitric Acid for nonmetal anions Sodium Hydroxide + aluminium powder for Nitrate Sodium Hydroxide for metal cations However, these tests may not work because of the presence of various ions in the sample at once.

Equipments needed:

 * 3L water container
 * 50mL HCl 1M
 * 1 pH probe
 * 1 temperature probe
 * 10 test tubes
 * 2 test tube stands
 * 1 dropper pipette
 * 1 250mL measuring cylinder
 * 1 10mL measuring cylinder

After discussion with the others in the other sciences, it's decided that we will be comparing 2 different locations.

Finalized procedure for chemistry will be to detect the presence of the heavy metals in the water sample. First water turbidity will be measured to see how much soluble metals there are in the water. These metals come from to soil are are soil sediments. We decided to test for Iron, Calcium and Lead, since they are the easiest soil sediments to test for with the equipment we have available.

Results:
Secchi disk depth: A-22cm, B-20cm This is extremely turbid water, which means there are a high concentration of soluble particles in the water.

Total Hardness: A - Original: 20ppm, Final: 100 ppm B - Original: 100ppm, Final: 188pmm



Calcium Hardness A - Original: 20ppm, Final: 68ppm B - Original: 68ppm, Final: 120ppm



Iron Hardness: A- 1ppm B- 2ppm

Recommended Iron Hardness: 0.3 ppm

Test for Lead: No precipitation visible