Ok, a solution is prepared with 70.0g of HN03 and 130.0g of H2O. It has a density of 1.21 g/mL. What is its molarity? Please help I've been stuck on this for some time, there has to be some conversion factor I'm missing I just can't find anything in my textbook strangely enough...
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molarity is defined as the #moles/1000 mL of solution - you have to find how many moles of HNO3 will be present in 1000 mL of solution.
the density is provided for you to convert the g into mL.
total weight =70 + 130 g = 200 g
=> total volume = (200 g)/(1.21 g/mL) => 165.289 mL
note that 70 g HNO3 = 70/62.985 = 1.111 moles of HNO3
since 165.289 mL contains 1.111 moles of HNO3
=> 1000 mL will contain (1.111 * 1000)/165.289 = 6.724 moles of HNO3
=> the molarity of the solution is 6.724.
Enjoy the solution :-)
the density is provided for you to convert the g into mL.
total weight =70 + 130 g = 200 g
=> total volume = (200 g)/(1.21 g/mL) => 165.289 mL
note that 70 g HNO3 = 70/62.985 = 1.111 moles of HNO3
since 165.289 mL contains 1.111 moles of HNO3
=> 1000 mL will contain (1.111 * 1000)/165.289 = 6.724 moles of HNO3
=> the molarity of the solution is 6.724.
Enjoy the solution :-)
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solution weighs 200g 200/1.21=ml of solution 70g of HNO3 is about 70/63 moles and molarity equals moles per volume.