Global Experiments on Chemistry. Kapil Tripathi Scientist-D VIGYAN PRASAR(DST ). International Year of Chemistry 2011. Year 2011 has been declared as the International Year of Chemistry.
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VP is creating awareness about Global Experiments among the teachers to perform the
experiments in their schools.
This includes following four experiments:
Measuring pH -The two most common measurements of pH involve using indicators or pH meters.
Indicators are weak acids that are coloured and that change colour when they undergo an acid-base reaction and (formally) lose the H+ ion. The reactions are usually reversible so that the indicator has two molecular forms: the acid and the base:
bromothymol blue → bromothymol blue-
acid form base form
The colour change in indicators usually occurs across a 10-fold change in H3O+ concentration
and socovers a change in pH of one.
pH meters – Instrument which measure the pH using glass electrode. more.
Testing the local water source
Chloride Cl-1 19.345
Sodium Na+1 10.752
Sulfate SO4-2 2.701
Magnesium Mg+2 1.295
Calcium Ca+2 0.416
Potassium K+1 0.390
Bicarbonate HCO3-1 0.145
Bromide Br-1 0.066
Borate BO3-3 0.027
Strontium Sr+2 0.013
Fluoride F-1 0.001
Clarification is the process used to remove solid debris from
natural or waste water and involves four steps:
(use 500 mL of your filtered water for this activity).
% water purified = volume collected X 100
Volume added to still