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Chem Question help

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Tea.bag:
I am having trouble answering the following questions. Can anyone help me? :o

1. To what volume of water must 10ml of 8.0M HCL be added in order to prepare a 0.50M HCL solution?

2. The chlorine in a 0.63g sample of a chlorinated pesticide, DDT (C14H9Cl5), is precipitated as silver chloride. What mass of silver chloride is formed?

Collin Li:
Question 1

Using





Since tells you the new volume: volume to be added is the difference between the new volume and the old volume.

Therefore, 150 mL must be added.

Collin Li:
Question 2

Tea.bag:
Thanks Coblin.

More questions coming soon.  :P

Tea.bag:
Got another question...

1. The organic compounds dimethyl ether and ethanol have the same molecular formula, , and the same molar mass; however they have different structural formulas.
A sample containing both ethanol and dimethyl ether is analysed by GLC using a flame ionisation detector.

a) Will the two compounds produce peaks with the same retention time? Explain you answer.
b) If the sample have the same concentration of both chemicals, will the peaks produced have the same area? Explain your answer.

2. Fluoride compounds are added to Melbourne's supplies of drinking water to give a concentration of fluoride ions of about 0.90 ppm.

a) What amount, in mol, of fluoride is present in 1.0g if Melbourne water?
b) How many fluoride ions would you swallow if you drank a 200 ml glass of Melbourne water?

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