dr. bob

posted by .

Use the data in Table 5.4 to calculate the partial pressure of He in dry air assuming that the total pressure is 1.0 atm. Assuming a temperature of 21°C, calculate the number of He atoms per cubic centimeter.

.00000524 - atmospheric composition of airnear sea level for He(info from table)

not a clue

  • dr. bob -

    What are the units here (for the composition of Helium at sea level)? percent? mols?

  • dr. bob -


  • dr. bob -

    In the Earth's atmosphere, the concentration of helium by volume (also called the "mole fraction") is 5.2 parts per million. At 1 atm and 21C, the molar density of air is
    1 mole /24,100 cm^3. Multiple that by the mole fraction and Avogadro's number for the number of He atoms per cm^3.
    I get 1.3*10^13.

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. Chemistry- partial pressures

    A sample of gas collected over water at 42 degrees C occupies a volume of one liter. The wet gas has a pressure of .986 atm. The gas is dried and the dry gas occupies 1.04 L with a pressure of 1.00 atm at 90 degrees C. Using this information, …
  2. Chemistry - Gas Laws

    Liquid helium at 4.2 K has a density of 0.147 g/mL. Suppose that a 1.00-L metal bottle that contains air at 118K and 1.0 atm pressure is sealed off. If we inject 120.0 mL of liquid helium and allow the entire system to warm to room …
  3. Chemsitry II

    The partial pressure of CH4(g) is 0.185 atm and that of O2(g) is 0.300 atm in a mixture of the two gases. a) What is the mole fraction of each gas in the mixture?
  4. Chemsitry II

    mole fraction is equal to partial pressure divided by the total pressure Total pressure= sum of partial pressure use PV=nRT where n= number of moles equation become PV/RT=n make sure to convert the temperature to Kelvin and to use …
  5. re-apchem post

    a 2L container is charged with 2atm of O2 at 298 Kelvin. Ch4(g) + 2O2(g) --> CO2(g) + 2H20(g) calculate the partial pressure of methane needed to react completely with the O2 in the vessel. What is the total pressure after the reaction …
  6. 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 …
  7. chemistry 106

    Dry air near sea level has the following composition by volume: N2, 78.08 percent; O2, 20.94 percent; Ar, 0.93 percent; CO2, 0.05 percent. The atmospheric pressure is 1.00 atm. (Hint: Since volume is proportional to the number of moles …

    Dr BOB can you explain this to me. I am so struggling with this subject. during a typical breathing cycle the CO2 concentration in the expired air rises to a peak of 4.6% by volume. Calculate the partial pressure of the CO2 at this …

    Dr BOB can you explain this to me. I am so struggling with this subject. NO one has helped me on this one yet can anyone help me?
  10. college chemistry

    The air in a typical La Crosse basement contains 53 atoms of 222Rn per liter. A. If the basement has 950 ft^2 of floor space and is 8.0 feet tall, how many 222Rn atoms are there in the whole basement?

More Similar Questions