Mass of NaCl
= mass of Nacl + mass of H2O
= (23 + 35.5) + 80g
= 58.5 + 80g = 138.5g
Since 39.8g at 100°C = 35.9g at 15°C
138.5g at 100°C = Xg at 15°C
X = 138.5 × 35.9/39.8g
= 124.9g at 15°C
Hence mass of Nacl precipitated
= 138.5 - 124.9g
= 13.6g of Nacl
(i) increasing the surface area
By adding catalyst to the reaction
(ii)0.896dm^3 of CO2 was produced by 4g of caco3
If 100g of caco3-----1mole of co2(22.4dm3)
(i)atom the smallest particle of a chemical element that can exist.
(ii)molecule is a group of atoms bonded
together, representing the smallest fundamental unit of a chemical compound that can take part in a chemical reaction.
(i)Temporary hardness is caused by dissolved calcium hydrogencarbonate
(ii)Permanent hardness is caused by dissolved calcium sulfate.
(i)Temporary Hardness can be Removed By Boiling
(ii)Permanent hardness can be removed by ... washing soda (sodium carbonate); ion exchange; the use of polyphosphate water softeners.
(i)Calcium ions in the water are good for children's teeth and bones.
(ii)Some brewers prefer using hard water for making beer.
(i)It is more difficult to form a lather with soap.
(ii)Scum may form in a reaction with soap, wasting the soap.
A saturated solution is a chemical solution containing the maximum concentration of a solute dissolved in the solvent.