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T-Mobile 3:00 PM K Chem 131 Practice Exam 5.docx 1 16, What is the volume at STP

ID: 105124 • Letter: T

Question

T-Mobile 3:00 PM K Chem 131 Practice Exam 5.docx 1 16, What is the volume at STP occupied by a gas mixture having 0.753 mol nitrogen, 0.940 mol hydrogen and 3.32 mol of oxygen? (5 points) b Each component contributes to the pressure in the above example. What is the partial pressure (in atmospheres) of each of the components above if the pressure is increased to 6.78 17. Calculate the pH of an aqueous solution of acetic acid (CH,COOH), K, = 1 .9 x 10", where the initial concentration is 0.100 molar. ( 10 pts) CH,COOH HOCH,CooHO a Set up and complete the Initial, Change, Equilibrium chart. b Calculate the equilibrium concentration of HO c. Calculate the pH. Initial Change Courses Calendar To Do Notifications Inbox

Explanation / Answer

16.

a) total mole = mole of N2 + mole of H2 + mole of O2

= 0.753 + 0.940 + 3.32 = 5.013 mole

According to avogadro's law at STP 1 mole gas occupy volume = 22.414 liter

then 5.013 mole gas occupy volume = 5.013 X 22.414 = 112.36 liter

at STP volume occupy by gas = 112.36 liter

b) first calculate mole fraction

total mole in cylinder = 5.013 mole

mole fraction = no. of mole of insivisual gas / total mole

mole fraction of N2 = 0.793 / 5.013 = 0.158

mole fraction of H2 = 0.940 / 5.013 = 0.187

mole fraction of O2 = 3.32 / 5.013 = 0.662

partial pressure = mole fraction X total pressure

partial pressure of N2 = 0.158 X 6.78 = 1.07 atm

partial pressure of H2 = 0.187 X 6.78 = 1.26 atm

partial pressure of O2 = 0.662 X 6.78 = 4.48 atm