[Heat]

Well, I need help with the next excercises.

GASES:

5.55 A compound of P and F was analyzed as follows:
Heating 0.2324 g of the compound in a 378-cm 3 container
turned all of it to gas, which had a pressure of
97.3 mmHg at 77°C. Then the gas was mixed with
calcium chloride solution, which turned all of the F to
0.2631 g of CaF 2 . Determine the molecular formula of
the compound.

5.56 A quantity of 0.225 g of a metal M (molar mass 5
27.0 g/mol) liberated 0.303 L of molecular hydrogen
(measured at 17°C and 741 mmHg) from an excess of
hydrochloric acid. Deduce from these data the corresponding
equation and write formulas for the oxide
and sulfate of M.

5.57 What is the mass of the solid NH 4 Cl formed when
73.0 g of NH 3 are mixed with an equal mass of HCl?
What is the volume of the gas remaining, measured at
14.0°C and 752 mmHg? What gas is it?

5.58 Dissolving 3.00 g of an impure sample of calcium
carbonate in hydrochloric acid produced 0.656 L of
carbon dioxide (measured at 20.0°C and 792 mmHg).
Calculate the percent by mass of calcium carbonate in
the sample. State any assumptions.

5.59 Calculate the mass in grams of hydrogen chloride produced
when 5.6 L of molecular hydrogen measured at
STP react with an excess of molecular chlorine gas.

5.60 Ethanol (C 2 H 5 OH) burns in air:
C2H5OH(l) 1 O2(g) ¡CO2(g) 1 H2O(l)
Balance the equation and determine the volume of air
in liters at 35.0°C and 790 mmHg required to burn
227 g of ethanol. Assume that air is 21.0 percent O 2 by
volume.

5.65 Dry air near sea level has the following composition
by volume: N 2 , 78.08 percent; O 2 , 20.94 percent; Ar,
0.93 percent; CO 2 , 0.05 percent. The atmospheric
pressure is 1.00 atm. Calculate (a) the partial pressure
of each gas in atm and (b) the concentration of each
gas in moles per liter at 0°C. ( Hint: Because volume is
proportional to the number of moles present, mole
fractions of gases can be expressed as ratios of volumes
at the same temperature and pressure.)

5.69 Helium is mixed with oxygen gas for deep-sea divers.
Calculate the percent by volume of oxygen gas
in the mixture if the diver has to submerge to a depth
where the total pressure is 4.2 atm. The partial pressure
of oxygen is maintained at 0.20 atm at this
depth.

5.70 A sample of ammonia (NH 3 ) gas is completely decomposed
to nitrogen and hydrogen gases over heated
iron wool. If the total pressure is 866 mmHg, calculate
the partial pressures of N 2 and H 2 .

(Chemistry Raymond Chang 10th Edition)


[helpme]

[Leaf]

I took chem last year, and as soon as the final was over I forgot most of that stuff so I can't help. your best bet would be asking someone in your class for help, thats what I did :P

[Heat]

The test is tomorrow :/..I did 50 exercises, but I can't do the others.

[Donut]

Ahh Thermodynamics and pressures.

I'm sorry that I can't help you, because I failed the test on this in freshmen year also.
(Yes I took chem freshmen year)

[SmG Dragonrage]

I haven't taken chem for like five years. Brightstorm.com or khanacademy.org might help. Or possibly cheggs homework help section.

[Heat]

I can solve all exercises. :D

[Rebel]

ahh chemistry.....
*looks a problems*
*faints*

[Heat]

And I get a 4.6 on my exam :P

[SmG Dragonrage]

Out of what? It would be easier to know of that was goodif u just put it into percentage

[Heat]

4.6/5.0 or 92% :D