# AP Chemistry

1) Calculate the volume of air at 30 degrees C and 1.00 atm that is needed to burn completely 10.0 grams of propane. Assume that air is 21.0 percent O2 by volume.

2) Assuming all of the heat evolved in burning 30.0 g of propane is transferred to 8.00 kg of water (specific heat = 4.18 j/goK), calculate the increase in temperature of the water.

1. Write the balanced equation.
C3H8 + 5O2 ==> 3CO2 + 4H2O

Convert 10g C3H8 to mols, use the equation to convert mols C3H8 to mols O2, and use that and PV=nRT to calculate volume at the non-standard conditions. That divided by 0.21 should be the volume of air. Check my thinking. Check my work.

2. Different problem but same equation. Are you given the delta H for the reaction? If it isn't given then you must look it up in a set of tables. Use the value in the tables (usually given in kJ/mol) to calculate deltaH for the reaction. Then q=increase in T.
q = mass x specific heat x deltaT. Delta T will be the increase in T.

Post your work if you get stuck.

To clarify, q is not the increase in T; rather, q is the heat transferred to the water; q = increase in heat and that is used to calculate T.

Okay, for 2 I got the delta H, which is -103.7 kJ/mol. So is the equation something like:

(.682 mol C3H8)(-103.7kJ/mol)=(800g)(4.18J/g-K)(delta T)

and I solve for Delta T?

Oh, nevermind I figured this out, thanks DrBob222 for the help!

1. 0
2. 0
3. 15
1. ahahhhaaaa.

1. 0
2. 0
posted by zoozoo

## Similar Questions

1. ### Chemistry

1. Calculate the number of molecules in a deep breath of air whose volume is 2.15 L at body temperature, 36 degrees Celsius, and a pressure of 740 torr. 2.A fixed quantity of gas at 24 degrees Celsius exhibits a pressure of 740

asked by Emory on November 3, 2009
2. ### Chemistry

Apply the gas laws to determine how many grams of sodium azide (NaN3) are needed to fill the air bag of your vehicle to a volume of 79.0 L at 35.0 degrees celsius and 1.00 atm. The reaction occurring in the air bag can be

asked by Dani on December 9, 2011
3. ### Chem hw!

1. What pressure would be needed to compress 25.1 mL of hydrogen at 1.01 atm to 25% of its original volume? 2. If the pressure on a 1.04-L sample of gas is doubled at constant temperature, what will be the new volume of the gas?

asked by Teisha on March 11, 2010
4. ### Chem hw!

1. What pressure would be needed to compress 25.1 mL of hydrogen at 1.01 atm to 25% of its original volume? 2. If the pressure on a 1.04-L sample of gas is doubled at constant temperature, what will be the new volume of the gas?

asked by Teisha on March 11, 2010
5. ### sciencee

1. What pressure would be needed to compress 25.1 mL of hydrogen at 1.01 atm to 25% of its original volume? 2. If the pressure on a 1.04-L sample of gas is doubled at constant temperature, what will be the new volume of the gas?

asked by Teisha on March 10, 2010
6. ### ap chem

Assuming the volumes of all gases in the reaction are measured at the same temperature and pressure, calculate the volume of water vapor obtainable by the explosive reaction of a mixture of 725mL of hydrogen gas and 325mL of

asked by Alicia on December 29, 2007
7. ### Chemistry

The adult blue whale has a lung capacity of 5.0*10^3L. Calculate the mass of air (assume an average molar mass 28.98 g/mol ) contained in an adult blue whale’s lungs at 0.3 degrees Celcius and 1.10 atm., assuming the air behaves

asked by Steffani on December 6, 2011
8. ### Physics sph 212

A person takes in a breath of 0 degrees celsius air and holds it until it warms to 37 degrees celsius. The air has an initial volume of 0.700L and a mass of 9.00*10^-4kg. Determine a. the work done by the air on the lungs if the

asked by Tiera on April 6, 2012
9. ### Chemistry

A driving bell is a container open at the bottom. As the bell descends, the water level inside changes so that the pressure inside equals the pressure outside. Intially the volume of air is 8.58m^3 at 1.020 atm and 20 degrees C.

asked by Lauren on October 23, 2007
10. ### Chemistry

How many liters of air (78 percent N2, 22 percent O2 by volume) at 20 degrees Celsius and 1.00 atm are needed for the complete combustion of 1.0 L of octane, C8H18, a typical gasoline component that has a density of 0.70 g/mL?

asked by Star on April 28, 2011
11. ### AP Chem

Can someone please check these problems? 34. You fill a balloon with helium gas to a volume of 2.68 L at 23 degrees C and 789 mmHg. Now you release the balloon. What would be the volume of helium if its pressure changes to 632

asked by Anna on November 13, 2008

More Similar Questions