The concentration of Cu2+ ions in the water (which also contains sulfate ions) discharged from a certain industrial plant is determined by adding excess sodium sulfide (Na2S) solution to 0.800 L of the water. The molecular equation is Na2S(aq) + CuSO4(aq) → Na2SO4(aq) + CuS(s) Calculate the molar concentration of Cu2+ in the water sample if 0.0183 g of solid CuS is formed

0.000239 M

Explanation:

Na2S(aq) + CuSO4(aq) → Na2SO4(aq) + CuS(s)

molar mass of  = 159.609 g/mol

molar mass of CuS = 95.611 g/mol

if 159.609 g/mol yielded 95.611 g/mol of CuS

then x g of CuSO4 that yielded 0.0183 g = 159.609 × 0.0183 / 95.611 = 0.0305 g

molar concentration = mole / volume in liters

number of mole of CuSO4 in the water sample = 0.0305 g / 159.609 g/mol = 0.000191 moles

molar concentration of CuSO4 = 0.000191 moles  / 0.8 L = 0.000239 M

since when 1 mole of CuSO4  will dissociate to produce 1 mole of  Cu2+

the molar concentration Cu2+ = 0.000239 M

on passing the small ampere of electric current through the tube made of ar and hg of cfl generates uv rays which excites the fluorescent and thus emits the high radiation by consumption of just 5- 12 w in comparison to incandescent light which requires more power such as around 40 - 55 w to lighten.

moreover the life span of fluorescent or cfl is around 8000 h whereas the life span of incandescent is around 1200 h

hence, the building installed with incandescent lights bears more electricity bill.