ATAR Notes: Forum
VCE Stuff => VCE Science => VCE Mathematics/Science/Technology => VCE Subjects + Help => VCE Chemistry => Topic started by: mystikal on June 06, 2009, 06:28:23 pm
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Question 20 of Multiple Choice
can someone explain to me how that works?
Question 5 e)
I just put down it is going to be less due to the increase in molar mass, the answer said it is approximately half, do i still get the mark?
Question 6 b)
I put down distillation for the answer because it says "pure", but the answer is fractional distillation, do i get the mark?
Also what does it mean by 'percentage yield'
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o yea i forgot to ask that if it asks for semi structral formula can we still put ch2=ch2 like showing the double bond like that?
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yeah you can for the CH2=CH2
Percentage yield is where you calculate how mcuh you actually obtained ; and compare it to what was expected to be produced, which you work out through mole ratio and find mass etc.
obtained/expected x100% = percentage yield
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MCQ20
steps 2, 4 and 5 are fine
step 1 would cause c(acid) to be lower -> the titre would be higher -> c(base) would be calculated higher
step 3 would cause n(base) to be higher -> titre would be higher -> c(base) would be calculated higher
thus the answer is C