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VCE Stuff => VCE Science => VCE Mathematics/Science/Technology => VCE Subjects + Help => VCE Chemistry => Topic started by: cipherpol on November 07, 2009, 06:36:36 pm

Title: stoich question
Post by: cipherpol on November 07, 2009, 06:36:36 pm: A solution contains a mixture of two salts, potassium nitrate and potassium sulfate. If the concentration of potassium ions is 1.4 M and the concentration of nitrate ions is 0.6 M, what is the concentration of the sulfate ions?

Thanks.
Title: Re: stoich question
Post by: Edmund on November 07, 2009, 06:47:27 pm: Since Concentration is proportional to number of moles, we can work in terms of concentration.

Potassium nitrate: $KNO_3$

Therefore ratio of nitrate to potassium is 1:1, and there are 0.6M of nitrate ions (given), and we can deduce that there are 0.6M of potassium ions.

Potassium sulfate: $K_2 SO_4$

There will be 1.4M - 0.6M = 0.8M of potassium ions

Therefore there will be 0.8M/2 = 0.4M of sulfate ions

(Someone please confirm if this is right)
Title: Re: stoich question
Post by: cipherpol on November 07, 2009, 06:50:52 pm: Yep, it's correct, thanks Edmund.