Question

Questions form part a, b and c

?2,4 SAMPLE NO. example trial 1 "trial 2 21.123 a PERCENTAGE or Bao,.mp"?"UNKHOwN dI 1. Weight of evaporating dish (@) 2. Weight of evaporating dish and unknown ( *3. Weight of evaporating dish and residue 22.334 42.030 22.193 42.67 (irst heating) (g) 4 Weight of evaporating dishand residue (second heating) (g) 22.187 CALCULATIONS/RESULTS/CONCLUSIONS A. REVERSIBILITY OF HYDRATION 1. Is the dehydration and hydration of Cuso, SH,0 reversible? Explain your answer 1. Which compounds are deliquescent? (from your experiment) 2. Are all compounds deliquescent? C. DISTINGUISHING HYDRATES FROM NONHYDRATES 1. Which compounds produce water upon heating? (from your experiments) (TAJUOJA ? 2. Which compounds form hydrates? (from your experiment) Explain your answer. ?? mbers en s with astens s represent data take in the lab while the o heru bers Trial 2 is done il some problem occurred during trial 1 terms were cal ulated from the lab data.

Answer 1

Part A

Yes, dehydration and hydration of cuso4.5h2o is a reversible process. When the compound is having water molecules i.e.

water of hydration it is blue in colour and crystalline in nature when it is heated then it loses its colour and turns to a white powdery substance called as anhydrous cuso4. This anhydrous substance can be hydrated by adding water to it which was obtained while dehydrating the salt.

Part B

1. Deliquescent are those compounds which absorbs moisture from the atmosphere and turns to a liquid phase or turns to solution. This happens when vapour pressure of the solution formed is less than that of vapour pressure of water vapours in air.

2. No, not all compounds are deliquescent. There are many compounds that doesn't absorb water from atmosphere such as wax. Although all chlorides except nacl are deliquescent .

Part C

1. Those compounds which have water in their crystalline structure produce water when heated. Like cuso4.5h2o .

2. Compounds which are able to accommodate water in their Crystal structure without much affecting the properties are ablr to form hydrates. These loose water upon heating and also rehydrated when water added to them.