± Electrolysis and Current A student designs an ammeter (a device that measures
ID: 1035481 • Letter: #
Question
± Electrolysis and Current
A student designs an ammeter (a device that measures electrical current) that is based on the electrolysis of water into hydrogen and oxygen gases. When electrical current of unknown magnitude is run through the device for 1.50 min , 14.7 mL of water-saturated H2(g) is collected. The temperature and pressure of the system are 25 ?C and 715 torr.
The vapor pressure of water changes with temperature, as shown here.
Part A
How many moles of hydrogen gas are produced?
Express your answer to three significant figures and include the appropriate units.
T (?C) P (torr) 21 18.7 22 19.8 23 21.1 24 22.4 25 23.8 26 25.2 27 26.7 28 28.4 29 30.0 30 31.8Explanation / Answer
Solution :-
PV=nRT to find n, the moles of hydrogen gas.
V= 1.47x10^-2 L
P= 715 torr-VP of water at 25C (about 25 torr; look it up in Wikipedia)
in atm
p = 715 * 0.00131578947 = 0.940789471 atm
T= 298.2K
R = 0.08206 L·atm·mol-1·K-1.
n ( moles of hydrogen gas ) = 5.0256*10^-4 mol
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.