Login

Search the forums now!

Welcome, Guest. Please login or register.

November 01, 2025, 12:20:57 pm
Pages: [1]   Go Down

Author Topic: Unit 1/2 question  (Read 1230 times)  Share 

0 Members and 1 Guest are viewing this topic.

Einstein

  • Guest
Unit 1/2 question
« on: March 03, 2014, 08:17:46 pm »
0
A 1.124 g sample of CaSO4 crystals was heated to drive off the water of crystallisation. When completely dry, a residue of 0.889 g was obtained. Determine the empirical formula of the hydrated compound.
Logged

nhmn0301

  • Victorian
  • Forum Obsessive
  • ***
  • Posts: 379
  • Respect: +15
  • School: The University of Melboure
  • School Grad Year: 2017
Re: Unit 1/2 question
« Reply #1 on: March 03, 2014, 08:42:37 pm »
0
Quote from: Einstein on March 03, 2014, 08:17:46 pm
A 1.124 g sample of CaSO4 crystals was heated to drive off the water of crystallisation. When completely dry, a residue of 0.889 g was obtained. Determine the empirical formula of the hydrated compound.
Heating crystal to drive off water meaning 0.889 is the mass of anhydrous (= no water ) crystals. Hence, you have mass of crystals, subtract it from the total mass, you have the mass of water that has been driven off. From here, use n=m/M, find the mole ratio between crystals and water and determine empirical formula. Try this out, you should get CaSO4.2H2O
Hope this helps.
Logged
2015-2017: Bachelor of Biomedicine

Einstein

  • Guest
Re: Unit 1/2 question
« Reply #2 on: March 03, 2014, 09:03:04 pm »
0
yeah i was stupid and did 0.235/1 (which is hydrogen) forgot to do 0.235/18 (H20)
Logged
Pages: [1]   Go Up