Mass percent concentration: Dissolving

biostudent123

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10 years ago

What is the mass percent concentration of the following solutions?

a)Dissolve 0.695mol of citric acid, C6H8O7, in 1.00 kg of water.

b)Dissolve 0.125mg of KBr in 5.00 mL of water.

c)Dissolve 5.70g of aspirin, C9H8O4, in 145 g of dichloromethane, CH2Cl2.

I tried using mass percent= mass component/total mass solution X 100%.... But i dont know what the standard unit conversion is for the mass component or total mass solution ( g,kg,Moles etc)

Molality and Molarity are every specific on the units that are used in equation*

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padre

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10 years ago

Similar problems

Dissolve 0.195 mg of KBr in 5.00 ml of water.

Dissolve 4.80g of aspirin,C9H8O4 , in 145g of dichloromethane,CH2Cl2 .

Quote

Dissolve 0.195 mg of KBr in 5.00 ml of water.

0.195 mg / 5000.195 mg times 100 = 0.00390 % KBr
======================================...

Dissolve 4.80g of aspirin,C9H8O4 , in 145g of dichloromethane,CH2Cl2

4.80 g / 149.8 g times 100 = 3.20 % aspirin

Hope this shines some light,

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biostudent123 Author

wrote...

10 years ago

Thank you so much, i got two correct after using those as template, i dont know how to do this one

a)Dissolve 0.695mol of citric acid, C6H8O7, in 1.00 kg of water.

I tried dividing 0.695 with 1.00kg, but answer came out wrong.

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barry

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10 years ago

Quote from: biostudent123 (10 years ago)

1.00 kg of water.

1 ml = 1 g

1000 g = 1 kg

So, it's 1000 grams of water.

Now, do you know how to go from moles to mass (mg) ?

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biostudent123 Author

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10 years ago

yes it became 133500 mg , i then divided that with(133500+1000)....answer became 0.99, but it turned out wrong, What is standard units for the mass of component (is it always mg ? )

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barry

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10 years ago

Quote from: biostudent123 (10 years ago)

133500 mg

How did you get this? Please show me

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biostudent123 Author

wrote...

10 years ago

I turned 0.315 into Grams then divded it by Kbr's molecular weight,

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