ap chem

A mole of helium gas contains 6.02x10^23 helium atoms. How many helium atoms are there in a micromole of helium? How many moles of helium does 1.25x10^20 atoms of helium represent?

~I have no idea how to start or what the value of a micromole is? Constructive help would be great... thanx

If there are 6.02x10^23 atoms in a mole of He atoms, then how many mols must there be in 1.25x10^20 atoms. You know 1.25x10^20 atoms MUST be less than 1 mole. Or look at it another way.
How many mols in 6.02x10^23 atoms? 1.0
How many mols in 3.01x10^23 atoms? 0.5
How many mols in 1.5x10^23 atoms?
How many mols in 0.75x10^23 atoms?
Get the idea? How many mols are there in 1.25x10^20 atoms.

A micrometer is 1x10-6meters.
A microliter is 1x10-6 liters.
A micromole must be 1x10-6 mols. So you want to know the number of atoms in 1x10-6 mol He atoms. Show your work if you get stuck and I can give you other hints. But I predict you won't need them.

  1. 👍
  2. 👎
  3. 👁
  1. 1x10^-6 divided by 6.02x10^23 equals 6.02x10^17
    1.25x10^20 divided by 6.02x10^23 equals 2.08x10^-4

    1. 👍
    2. 👎

Respond to this Question

First Name

Your Response

Similar Questions

  1. Thermodynamics

    An insulated rigid tank contains 1.5 kg of helium at 30∘C and 500 kPa. A paddle wheel with a power rating of 0.1 kW is operated within the tank for 30 minutes. Cvof helium = 3.12 KJ/Kg.K Problem 7A. Calculate the net work done

  2. Chemistry

    A helium balloon contains 0.50 g of helium. Given the molecular weight of helium is 4.0 g/mol, how many moles of helium does it contain?

  3. Physics

    A sample of helium behaves as an ideal gas as it is heated at constant pressure from 273 K to 353 K. If 25.0 J of work is done by the gas during this process, what is the mass of helium present?

  4. Chemistry

    A 334-mL cylinder for use in chemistry lectures contains 5.225 g of helium at 23 C. How many grams of helium must be releasedto reduce the pressure to 75 atm assuming ideal gas behavior?

  1. Science

    if 0.75 mole of helium gas occupies a volume of 1.5. what volume will 1.2 mole helium occupy at the same teperature and pressure?

  2. Chemistry

    A sample of methane (CH4) gas contains a small amount of helium. Calculate the volume percentage of helium if the density of the sample is 0.70902 g/L t 273K and 1.00 atm. I know that the sample is at STP and that the 1 mole of

  3. Chemistry

    a sample of helium gas has a volume of 1.25L at -125celcius and 50.0atm. the gas is compressed at 50.0 atm to volume of 325ml. what is the final temperature of the helium gas in Celcius

  4. Chemistry

    Assume the diameter of a neutral helium atom is 1.40 x 10^(2)pm. Suppose that we could line up the helium atoms side by side in contact with one another. How many atoms would it take to make the distance 5.80 cm from end to end?

  1. Chemistry

    A helium balloon contains 0.54g of helium. Given the molecular weight of helium is 4.0 g/mol, how many moles of helium does it contain?

  2. Science

    Helium gas is added to a ballon already partially filled with helium gas the balloon inflated because the

  3. CHEM

    How many grams of helium must be added to a balloon containing 8.00 g of helium gas to double its volume. Assume no temp or pressure change.

  4. General Chemistry

    A cylinder with a movable piston contains 2.00g of helium,He, at room temperature. More helium was added to the cylinder and the volume was adjusted so that the gas pressure remained the same. How many grams of helium were added

You can view more similar questions or ask a new question.