Gchem percent and density problem

[sony102]

---

Members don't see this ad.

1) What is the molality of 85% phosphoric acid, H3PO4, if the density of the solution is 1.70 g/ml?

A.1000 * (1.70/1) * (100.0 / 15.0) * (1.70/1) * (85.0 / 100.0) * (1/98) m
B.1000 * (1/1.70) * (100.0 / 15.0) * (1.70/1) * (85.0 / 100.0) * (1/98) m
C.1000 * (1/1.70) * (100.0 / 15.0) * (1/1.70) * (85.0 / 100.0) * (1/98) m
D.1000 * (1/1.70) * (15.0 / 100.0) * (1.70/1) * (85.0 / 100.0) * (1/98) m
E.1000 * (1/1.70) * (100.0 / 15.0) * (1.70/1) * (100.0 / 85.0) * (1/98) m


answer is B, can someone please break it up into steps because I am totally lost 🙁

2) if you graph PV/T vs. P , or graph PV vs. V at constant T , the graph for both of these is a streight horizontal line, anyone knows why??

 

[sony102]

can someone please help me with this, its achiever problem, never mind about the second problem

 

[klutzy1987]

This was a really stupid problem as their answers are written so stupidly and confusingly. The correct answer should be
85g H3PO4/15g H2O*1000g/1kg *1mol/98g
(85)*(1000)/(15)(98)
That is the correct answer. If you look at their answer choices for some reason they use density. However choice B says this because if you look they have 1/1.7 * 1.7/1. This cancels out and they also have a 100 on top and on bottom which calcel out to give the right answer. However the creators of achiever were pretty dumb and i guess didnt know whatb they were doing because their answers are pretty stupid and much longer than necessary.

 

[sony102]

thanks for the answer and rant lol

 

[klutzy1987]

thanks for the answer and rant lol

LOL i despise achiever if you cant tell. They kill your confidence and they are way too easy in the RC. Awful representation of the actual DAT. It is only good for practicing taking a 4 hour test.