[mr.meeogy]

I was hit with a bout of food poisoning and missed 3 lecture classes and am way behind. I have some problems that I have no idea how to do. If you guys could just give me the specific equation I need for these problems, or show me specifically how to do these problems, it would be MUCH appreciated.

A sealed balloon is filled with 1.00 L of helium at 23°C and 1.00 atm. The balloon rises to a point in the atmosphere where the pressure is 190. torr and the temperature is -31°C. What is the change in volume of the balloon as it ascends from 1.00 atm to a pressure of 190. torr?

An ideal gas is contained in a cylinder with a volume of 5.0 multiplied by 102 mL at a temperature of 30°C and a pressure of 685. torr. The gas is then compressed to a volume of 25 mL, and the temperature is raised to 794.°C. What is the new pressure of the gas?

A 4.4 L flask contains 0.55 g O2 at a temperature of 15°C. What is the pressure (in atm) inside the flask?

A bicycle tire is filled with air to a pressure of 76 psi, at a temperature of 29°C. Riding the bike on asphalt on a hot day increases the temperature of the tire to 58°C. The volume of the tire increases by 3.7%. What is the new pressure in the bicycle tire?

A hot-air balloon is filled with air to a volume of 2.77 multiplied by 103 m3 at 745 torr and 31°C. The air in the balloon is then heated to 46°C, causing the balloon to expand to a volume of 4.72 multiplied by 103 m3. What is the ratio of the number of moles of air in the heated balloon to the original number of moles of air in the balloon? (Hint: Openings in the balloon allow air to flow in and out. Thus the pressure in the balloon is always the same as that of the atmosphere.)

A sample of nitrogen gas was collected over water at 20.°C and a total pressure of 1.46 atm. A total volume of 2.85 multiplied by 102 mL was collected. What mass of nitrogen was collected? (At 20.°C the vapor pressure of water is 17.5 torr.)

A mixture of 1.43 g of H2 and 1.90 g of He exerts a pressure of 0.480 atm. What is the partial pressure of each gas present in the mixture?

Silicon tetrachloride (SiCl4) and trichlorosilane (SiHCl3) are both starting materials for the production of electronics grade silicon. Calculate the densities of pure SiCl4 and pure SiHCl3 vapor at 98°C and 754 torr.
silicon tetrachloride

A compound has the empirical formula CHCl. A 256 mL flask, at 373 K and 750. torr, contains 0.800 g of the gaseous compound. Give the molecular formula. (Type your answer using the format CO2 for CO2.)

Urea (H2NCONH2) is used extensively as a nitrogen source in fertilizers. It is produced commercially from the reaction of ammonia and carbon dioxide.

2 NH3(g) + CO2(g) ----> heat pressure H2NCONH2(s) + H2O(g)

Ammonia gas at 223°C and 90. atm flows into a reactor at a rate of 590. L/min. Carbon dioxide at 223°C and 46 atm flows into the reactor at a rate of 600. L/min. What mass of urea is produced per minute by this reaction assuming 100% yield?

Air bags are activated when a severe impact causes a steel ball to compress a spring and electrically ignite a detonator cap. This causes sodium azide (NaN3) to decompose explosively according to the following reaction.

2 NaN3(s) ---> 2 Na(s) + 3 N2(g)
What mass of NaN3(s) must be reacted in order to inflate an air bag to 67.3 L at STP?

Calculate the average kinetic energies of the CH4 and N2 molecules at 282 K and 565 K.

Calculate the root mean square velocities of CH4 and N2 molecules at 263 K and 553 K.

The rate of effusion of a particular gas was measured and found to be 25.0 mL/min. Under the same conditions, the rate of effusion of pure methane (CH4) gas is 45.6 mL/min. What is the molar mass of the unknown gas?

It took 5.0 minutes for 1.0 L helium to effuse through a porous barrier. How long will it take for 1.0 L Cl2 gas to effuse under identical conditions?

A 2.747 g sample of manganese metal is reacted with excess HCl gas to produce 3.48 L of H2(g) at 396 K and 0.934 atm and a manganese chloride compound (MnClx). What is the formula of the manganese chloride compound produced in the reaction? (Type your answer using the format CO2 for CO2.)

For a 1.68 L sample containing 1.54 mol of CO2 at 37°C, calculate the pressure using the following equations.
(a) the ideal gas equation

(b) the van der Waals equation

Methanol, CH3OH, can be produced by the following reaction.

CO(g) + 2 H2(g)---> CH3OH(g)
Hydrogen at STP flows into a reactor at a rate of 15.0 L/min. Carbon monoxide at STP flows into the reactor at a rate of 25.0 L/min. If 5.90 g of methanol is produced per minute, what is the percent yield of the reaction?

I know thats a bunch of questions, but I'm not asking that you guys do them all for me. Even just telling me the specific equation I need to solve one of these problems would be very helpful. Thanks in advance!

[Borek]

These are mostly applications of ideal gas law - pV=nRT.

Sorry, but you won't get any help in this format - that's not the way forum works. We can help you solve particular question, once you will show what you already know and how you have tried to solve.

A sealed balloon is filled with 1.00 L of helium at 23°C and 1.00 atm. The balloon rises to a point in the atmosphere where the pressure is 190. torr and the temperature is -31°C. What is the change in volume of the balloon as it ascends from 1.00 atm to a pressure of 190. torr?

Initial pressure, volume and temperature are enough to calculate number of moles of helium. Balloon is sealed - that basically means amount of gas doesn't change. Use pV=nRT again to calculate new volume.

You will need R for that:

http://en.wikipedia.org/wiki/Ideal_gas_constant

[billnotgatez]

Make sure that all the value has been converted to the same units
For instance you can convert to atm from torr

Make sure you use absolute values
Example do not use Celsius use Kelvin

[mr.meeogy]

These are mostly applications of ideal gas law - pV=nRT.

Sorry, but you won't get any help in this format - that's not the way forum works. We can help you solve particular question, once you will show what you already know and how you have tried to solve.

A sealed balloon is filled with 1.00 L of helium at 23°C and 1.00 atm. The balloon rises to a point in the atmosphere where the pressure is 190. torr and the temperature is -31°C. What is the change in volume of the balloon as it ascends from 1.00 atm to a pressure of 190. torr?

Initial pressure, volume and temperature are enough to calculate number of moles of helium. Balloon is sealed - that basically means amount of gas doesn't change. Use pV=nRT again to calculate new volume.

You will need R for that:

http://en.wikipedia.org/wiki/Ideal_gas_constant

I did all that, and in the end I get 3.27 L. I have rechecked my work and answer many times and keep getting 3.27, but it seems to be wrong.

I did all the problems that require PV=nRT, but how would I go about solving a problem like this one?

A mixture of 1.43 g of H2 and 1.90 g of He exerts a pressure of 0.480 atm. What is the partial pressure of each gas present in the mixture?

thanks again guys

[Borek]

3.27 L is a correct volume of He after balloon rises, but it is not what the question asks about - read it again. Be prepared for a facepalm

A mixture of 1.43 g of H2 and 1.90 g of He exerts a pressure of 0.480 atm. What is the partial pressure of each gas present in the mixture?

What is the definition of partial pressure? What is molar ratio of both gases?

[mr.meeogy]

3.27 L is a correct volume of He after balloon rises, but it is not what the question asks about - read it again. Be prepared for a facepalm

A mixture of 1.43 g of H2 and 1.90 g of He exerts a pressure of 0.480 atm. What is the partial pressure of each gas present in the mixture?

What is the definition of partial pressure? What is molar ratio of both gases?

  haha thanks, had to read the question like 3 times before I got that one.

And I kept trying to figure out using the mass ratio instead of the molar ratio, got that one too. thanks!

A sample of nitrogen gas was collected over water at 20.°C and a total pressure of 1.46 atm. A total volume of 2.85 x 102 mL was collected. What mass of nitrogen was collected? (At 20.°C the vapor pressure of water is 17.5 torr.)

I tried to use PV=nRT for this one, but if shoes a total pressure of 1.46 atm, and a vapor pressure. any ideas?

Silicon tetrachloride (SiCl4) and trichlorosilane (SiHCl3) are both starting materials for the production of electronics grade silicon. Calculate the densities of pure SiCl4 and pure SiHCl3 vapor at 98°C and 754 torr.

What equation would I need to calculate the density?

thanks in advance!

[Borek]

I tried to use PV=nRT for this one, but if shoes a total pressure of 1.46 atm, and a vapor pressure. any ideas?

You are given total pressure and partial pressure of water - what is partial pressure of nitrogen?

What equation would I need to calculate the density?

What is density definition? Assume you have 1 mole of gas.

[mr.meeogy]

I tried to use PV=nRT for this one, but if shoes a total pressure of 1.46 atm, and a vapor pressure. any ideas?

You are given total pressure and partial pressure of water - what is partial pressure of nitrogen?

What equation would I need to calculate the density?

What is density definition? Assume you have 1 mole of gas.

Cool, thanks, got those too.

Air bags are activated when a severe impact causes a steel ball to compress a spring and electrically ignite a detonator cap. This causes sodium azide (NaN3) to decompose explosively according to the following reaction.
2 NaN3(s) ---> 2 Na(s) + 3 N2(g)
What mass of NaN3(s) must be reacted in order to inflate an air bag to 67.3 L at STP?

Can you help me on how to start this problem also?

The rate of effusion of a particular gas was measured and found to be 25.0 mL/min. Under the same conditions, the rate of effusion of pure methane (CH4) gas is 45.6 mL/min. What is the molar mass of the unknown gas?

I have no idea how to even start on this one either.

thanks!

[Borek]

Can you help me on how to start this problem also?

Yes. But it is so simple you should be able to do it on your own.

I have no idea how to even start on this one either.

Graham's law of effusion.

[mr.meeogy]

Can you help me on how to start this problem also?

Yes. But it is so simple you should be able to do it on your own.

I have no idea how to even start on this one either.

Graham's law of effusion.

Im getting 53.23, but that doesnt seem to be correct.

And I still don't know where to start for the first one

[Borek]

Im getting 53.23, but that doesnt seem to be correct.

Why? Sig figs?

And I still don't know where to start for the first one

You are told amount of the product.