Gypsum, Calcium sulfate dihydrate(CaSO4-2H20) decomposes when heated to fork plaster of Paris, Calcium sulfate hemihydrate(CaSO4-1/2H20) and water. Builders and dentists must store plaster of Paris in airtight containers to prevent it from re-absorbing moisture from the air and changing back to gypsum. How many liters of water vapor are produced when 2.00 kg of gypsum is heated to 110° C to produce plaster of Paris?

let that person have a turn to speak : )

it is the most commonly accepted one

one negative thing it that it can kill water animals. another negative thing is it can cause the destruction of ecosystem. one way water pollution can be reduced is to conserve energy.

answer : third trial had the contaminated sample and the correct value for dhrxn should be 1000 kj/mol

explanation :

let us write down the given equations

equation 1 :

equation 2 :

equation 3 :

let us use hess's law to find out which 2 equations can be added to get the third equation.

let us reverse equation 2 and multiply it by 2. the new equation that we get is,

equation 4 :

let us add equation 1 & 4

the above equation is similar to equation 3 but has different value for dhrxn.

therefore third trial had the contaminated sample and the correct value for dhrxn should be 1000 kj/mol