sheanhung Posted June 27, 2006 Posted June 27, 2006 I have problem to determine the molarity of H2SO4 from 95%-98% H2SO4 solution with volume of 2.5 L stated on the bottle. Besides, i am not sure what is the meaning of 95%-98%. Is this percentage is in term of volume, number of moles or weight of H2SO4? If the molarity above is obtained, suppose i mix 1 volume this H2SO4 with 2 volume of water, what is the new molarity and number of moles of the diluted solution? These problems are killing me. :confused: Please help~! *Are these informations useful?* density of H2SO4 = 1.841 g/cm3 Molecular mass of H2SO4 = 98.08 g/mol
Primarygun Posted June 27, 2006 Posted June 27, 2006 98% means that the H2SO4 has 98% of the total weight of a sample of H2SO4 solution. In order to find out the molarity of the sulphuric acid, there's a pretty good method. Find out how many moles of H2SO4 are there in 1 dm^3 of water. Then it is equal to the molarity of the acid. what is the new molarity and number of moles of the diluted solution? Molarity= no. of mole of a substance / volume of solution. Since there's no departure of any H2SO4 molecules, it follows that there exists the amount of H2SO4 molecules. In this case , the molarity decreases as a result of the decrease in Volume of the solution
sheanhung Posted June 28, 2006 Author Posted June 28, 2006 I have calculated the molarity of the solution = 18 M After dilution, the new molarity is roughly 6M. However, is this possible to use this diluted solution outside fume cupboard? What i understand is 6M is too concentrated to be used outside fume cupboard. But, during my experiment, this diluted solution was placed on the bench only. Hmm......i think i have make mistake in calculation!
Primarygun Posted June 28, 2006 Posted June 28, 2006 But, during my experiment, this diluted solution was placed on the bench only. Hmm......i think i have make mistake in calculation What does this mean? You didn't use the diluted solution?
Darkblade48 Posted June 28, 2006 Posted June 28, 2006 After dilution' date=' the new molarity is roughly 6M. However, is this possible to use this diluted solution outside fume cupboard? What i understand is 6M is too concentrated to be used outside fume cupboard. [/quote'] I suppose technically, you could use even an 18M solution of H2SO4 outside a fume hood, depending on the type of experiment you are using it for. Of course, it's not recommended, but not everyone has access to a fume hood.
sheanhung Posted June 29, 2006 Author Posted June 29, 2006 What does this mean?You didn't use the diluted solution? The H2SO4 put on the bench is diluted solution already. Diluted solution is made by mixing 1 volume of H2SO4 and 2 volume of H2O. (Eg. 5mL of H2SO4 + 10mL of H2O). The molarity of the diluted H2SO4 should be 6M if the formula MV = MV is applied. Am i correct? If yes, is 6M of H2SO4 safe to use outside fume cupboard? (From mt knowledge, 6M is very concentrated too!)
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