my DAT is tomorrow, i need some help please.

[phosphorylation]

my DAT is tomorrow guys, im freaking out on three questions here. gen chem. please help. thanks in advance

whats the density of ammonia gas at 2.00 atm pressure and 25.0C (R=0.1 ATM L/molK)

You have a solution of 1 liter of H2O and 234 grams of NaCl, whats the osmotic pressure at STP (what the hell is STP?), given R=0.1 L atm mol K

What volume of HCL was added if 20mL of 1M NaOH is titrated with 1M HCL to produce a pH of 2.

these questions are really easy. I know. I don't know how to solve them though. I know I solved a bunch of them in my freshman year, but I can't seem to remember which methods I used; especially the last one. HELP!

thanks!

phospho

---

Members don't see this ad.

 

[g3k]

my DAT is tomorrow guys, im freaking out on three questions here. gen chem. please help. thanks in advance

whats the density of ammonia gas at 2.00 atm pressure and 25.0C (R=0.1 ATM L/molK)

You have a solution of 1 liter of H2O and 234 grams of NaCl, whats the osmotic pressure at STP (what the hell is STP?), given R=0.1 L atm mol K

What volume of HCL was added if 20mL of 1M NaOH is titrated with 1M HCL to produce a pH of 2.

these questions are really easy. I know. I don't know how to solve them though. I know I solved a bunch of them in my freshman year, but I can't seem to remember which methods I used; especially the last one. HELP!

thanks!

phospho

stp is standard temperature and pressure
I think the third answer is supposed to be the equation m1v1 =m2v2 check on that
I am not sure about the rest.. I will look up and get back to you
g3k

 

[shindrome]

i know it's much easier said than done, but i talked to justletmein when he finished along with 2 others who had taken the DAT recently. from what i've heard, gen chem is mostly concepts and theories and i heard that it's not too bad. don't lose any sleep over a problem like these, i don't think they'll ask you in that kind of detail. as for the last one, they might ask something like that but not on the level where you have to calculate pH after titration. try to relax...i know it's hard. im taking mine in 2 weeks. if you want help or a second opinion on what i said, PM justletmein. he'll give you all the low down on his experience. good luck tomorrow!

 

[g3k]

1) whats the density of ammonia gas at 2.00 atm pressure and 25.0C (R=0.1 ATM L/molK)

answer d= m/v = p*MM/RT

2)You have a solution of 1 liter of H2O and 234 grams of NaCl, whats the osmotic pressure at STP (what the hell is STP?), given R=0.1 L atm mol K

anwswer: pi = MRT
M= 4M (234/58)
T=273.15
substitute 4*273.15*.1 = 109.26 ( I am not too sure tho)


3)What volume of HCL was added if 20mL of 1M NaOH is titrated with 1M HCL to produce a pH of 2.

I think this goes m1v1 =m2v2