Chemistry

posted by .

We're doing gas problems in chemsitry. I have no idea where to even begin on this problem:

Air is 20% oxygen and 80% nitrogen. What is the mass of air in an automobile tire of 19.7 L and internal pressure of 46.7 PSI at 24 degrees celsius? (That pressure is the same as the 32 PSI difference you usually measure as the tire pressure 32 PSI + 14.7 PSI. You will have to use a weighted average for the molar mass of air.)

• Chemistry -

First the weighted average for the molar mass of air.
(0.8 x molar mass N2) +(0.2 x molar mass O2) = about 28.8 but you can do that more accurately.

Next the pressure of the tire in psi. We need that in atmospheres. I went to google and typed in 46.7 psi to atm and it returned 3.178 atm.

Now use PV = nRT
You know P, you know V from the problem, you know R (0.08206) and you know T (24 C + 273 = ??K). Calculate n = number of moles air.

Then moles = grams/molar mass. yOu know moles (n) and you know molar mass air (about 28.8 g/mol), calculate grams. That's your answer.

• Chemistry -

uo

Similar Questions

1. Physics

An apartment has a living room whose dimensions are 2.5 m 4.8 m 5.9 m. Assume that the air in the room is composed of 79% nitrogen (N2) and 21% oxygen (O2). At a temperature of 27°C and a pressure of 1.01 105 Pa, what is the mass …
2. Chemistry

Use Henry's law and the solubilities given below to calculate the total volume of nitrogen and oxygen gas that should bubble out of 1.6 L of water upon warming from 25 C to 50 C. Assume that the water is initially saturated with nitrogen …
3. Physics

An automobile tire contains a certain volume of air at 30 psig and 70 °F. The barometric pressure is 29.50 Hg. If due to running conditions, the temperature of air in the tire rises to 160 °F. What will be the gauge pressure?
4. chem 1p1

An automobile tire at 22oC with an internal volume of 20.0L is filled with air to a total pressure of 30. psi(pounds per square inch). [1 atm = 14.696 lb/in2]. What is the amount in moles of air in the tire?
5. Chemistry

Calculate the mass of air in an air-filled tire and the mass of helium in a helium-filled tire. What is the mass difference between the two?
6. Physics

An automobile tire is inflated with air originally at 10.0°C and normal atmospheric pressure. During the process, the air is compressed to 28.0% of its original volume and the temperature is increased to 36.0°C. a) What is the tire …
7. thermodynamics

an automobile tire contains a certain volume of air at 30 psig and 70 degree fahrenheit. The barometric pressure is 29.50 in.Hg. If due to running conditions the temperature of the air in the tire rises to 160 fahrenheit, what will …
8. chemistry

When magnesium burns in air, it reacts with oxygen and nitrogen, forming magnesium oxide and magnesium nitride. If 20.0L of air is available for this reaction, what mass of each compound can be formed?
9. chemistry

An automobile tire contains air at a pressure of 200. kPa and 25°C. The tire and its air heat up during traveling. If the pressure increases to 250. kPa but the volume remains the same, what is the temperature of the air inside the …
10. chemistry

Air consists of 21 % oxygen, 78 % nitrogen and 1 % argon by volume. Calculate: * (a)  the partial pressures in Pa, if total pressure is 1 atm,   * (b)  the concentration in mol m–3, of each gas at 273 K,   * (c)  the average …

More Similar Questions