##### need guidance with calculation in chem

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I need help finding the % (by mass) of sample recovered as KNO 3

mass of 150 ml beaker + KNO3: 78.01 g

mass of kno 3 recovered: 10.77 g (? is this right)

and the last thing is the first question i need to figure out the calculation to.

thank u

Oct 11th, 2015

I believe more information is needed to answer the question. It is incomplete as it is. But formulas are

mass of KNO3 recovered = (mass of 150 ml beaker + KNO3: 78.01 g) - mass of 150ml beaker)

% of mass recovered as KNO3

= mass of KNO3 recovered /Total mass of sample * 100%

Oct 11th, 2015

do u know wha tthe mass of sample is? i get it...but in lab we separated sand and KHO 3

would the mass of sample be the sand???

Oct 11th, 2015

No. It would be the sand + KNO3

Oct 11th, 2015

The mass of sample would be the mass of sand and KNO3 you were separating

Oct 11th, 2015

oh ok bc i was just confused whether to use sand in this since it was a differnet part of the lab but i guess i get it....

Oct 11th, 2015

so i would add the mass of KNO 3 and the sand together and divide mass of KNO3 recovered

Oct 11th, 2015

i got a 20 g sample of sand, now my entire answer is 2100 ? doesnt make sense???

Oct 11th, 2015

Am glad. Feel free to reach out to me if you have other questions.

Oct 11th, 2015

What is the mass of the beaker so that I can complete the question for you in full.

Oct 11th, 2015

67.24 g... i just wanna make sure im doing this right.

Oct 11th, 2015

mass of KNO3 recovered = (mass of 150 ml beaker + KNO3:) - mass of 150ml beaker)

mass of KNO3 recovered = 78.01g - 67.24 = 10.77 g

% of mass recovered as KNO3

= mass of KNO3 recovered /Total mass of sample * 100%

= 10.77g/ 20g  * 100%

= 53.85%

Oct 11th, 2015

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Oct 11th, 2015
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Oct 11th, 2015
Oct 20th, 2017
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