A student generates H2(g) over water using the reaction between zinc and hydrochloric acid
Zn(s)+ 2HCl(aq)---> ZnCl2(aq)+ H2(g)
Data:
Mass of vial and zinc 15.5082
mass of vial 15.3972
mass of zinc 0.111
final burette reading 45.30mL
barometric pressure: Patm 100.6kPa
temperature of trapped gas 24.3C
vapour pressure of water at 24.3 C: PH2O 3.004kPa
diff in solution lvls inside and outside burette 162mm H2O
calculate the pressure exerted by H2 gas alone in kPa and the kelvin temperature of the H2 gas
I know you're supposed to use the P lvl difference but im not quite sure what it is. the number im getting is 1.599 which rounded will be either 2 or 1.6
can some1 tell me how to do the next part?
5 answers
I answered your first post; even gave you an answer in kPa.
i know and i found a formula to do so. But i was wondering if you could tell me the formula to find the pressure exerted by H2 gas in kPa and also the one to find the kelvin temperature.
OK. But you only asked for the pressure exerted by the water. I don't remember the numbers; I'll go back and post at the original one so I can look at the numbers. If you have any follow up questions to my yet to be responses make a new post at the top of the page and include the the original post.
Wait, I see the numbers here so I'll just stay here.
I assume you are on the way to calculating the volume of H2 gas at STP.
Use (P1V1/T1) = (P2V2/T2)
P1 = 100.6 measured. The vapor pressue of H2O at 24.3 is 3.004 so subtract that. The pressure difference due to the water levels (is the water in the collection bottle HIGHER or LOWER than the water lever outside the bottle. ) is density*g*height = 1 g/cc x 9.8 m/s^2 x 0.162 m = 1.5876 kPa. If the water level is higher inside the bottle that means the pressure outside is higher than the pressure inside so you subtract the 1.5876 kPa also. Check my resoning. The result is P1 in kPa.
T1 is 273.15 + 24.3 = ?K
V1 is 45.30 mL. I think I've answered everything. By the way, you are allowed four significant figures so your mass should be 0.1110. In addition, with that many s.f. allowed, rounding to either 1.6 or 2.0 is not appropriate.
Use (P1V1/T1) = (P2V2/T2)
P1 = 100.6 measured. The vapor pressue of H2O at 24.3 is 3.004 so subtract that. The pressure difference due to the water levels (is the water in the collection bottle HIGHER or LOWER than the water lever outside the bottle. ) is density*g*height = 1 g/cc x 9.8 m/s^2 x 0.162 m = 1.5876 kPa. If the water level is higher inside the bottle that means the pressure outside is higher than the pressure inside so you subtract the 1.5876 kPa also. Check my resoning. The result is P1 in kPa.
T1 is 273.15 + 24.3 = ?K
V1 is 45.30 mL. I think I've answered everything. By the way, you are allowed four significant figures so your mass should be 0.1110. In addition, with that many s.f. allowed, rounding to either 1.6 or 2.0 is not appropriate.
1 answer