Good G'Chem Q.

This forum made possible through the generous support of SDN members, donors, and sponsors. Thank you.

dat_student

Junior Member
10+ Year Member
5+ Year Member
15+ Year Member
Advertisement - Members don't see this ad
We have 39.2% H2SO4 (by mass) in an aqueous solution whose specific gravity is 1.25. How many mili-liters of this solution is needed to make 100 ml of 0.2 M H2SO4. MW of H2SO4 = 98 g/mole.
 
dat_student said:
We have 39.2% H2SO4 (by mass) in an aqueous solution whose specific gravity is 1.25. How many mili-liters of this solution is needed to make 100 ml of 0.2 M H2SO4. MW of H2SO4 = 98 g/mole.

1.25 g/mL * 1000 mL = 1250 g of aqueous solution
39.2% * 1250 g = 490 g H2SO4
490 g H2SO4/ 98 g = 5 mole H2SO4
5 mole H2SO4 / 1 L = 5M H2SO4
0.1 L * 0.2 M H2SO4 = 5M * volume
volume = 0.004 L = 4mL of solution is needed
 
E. coli said:
1.25 g/mL * 1000 mL = 1250 g of aqueous solution
39.2% * 1250 g = 490 g H2SO4
490 g H2SO4/ 98 g = 5 mole H2SO4
5 mole H2SO4 / 1 L = 5M H2SO4
0.1 L * 0.2 M H2SO4 = 5M * volume
volume = 0.004 L = 4mL of solution is needed

correct
 
dat_student said:
We have 39.2% H2SO4 (by mass) in an aqueous solution whose specific gravity is 1.25. How many mili-liters of this solution is needed to make 100 ml of 0.2 M H2SO4. MW of H2SO4 = 98 g/mole.

where do u get these kind of questions? I don't remember learning about gravity stuffs during general chemistry 😛
 
E. coli said:
1.25 g/mL * 1000 mL = 1250 g of aqueous solution
39.2% * 1250 g = 490 g H2SO4
490 g H2SO4/ 98 g = 5 mole H2SO4
5 mole H2SO4 / 1 L = 5M H2SO4
0.1 L * 0.2 M H2SO4 = 5M * volume
volume = 0.004 L = 4mL of solution is needed

should i feel ashamed if i dont know how to do this problem?? even worse, will i score very low on the DATs????

these types of problem common on the DAT??
 
i don't think you need to know specific gravity. I can't even find it in my chem textbook (McMurry & Fay). The only course i remember learning it from is Fluid Mechanics.