U9 D1 & D2 Practice

After studying the mole concept, you should be able to calculate how many atoms, molecules, or formula units are in one mole of a substance. How many atoms are there in one mole of any substance?

• 6.02 x 10^23 atoms

• 3.01 x 10^23 atoms

• 12.04 x 10^23 atoms

• 1.00 x 10^23 atoms

When performing calculations involving the mole, it is important to use the correct number of significant figures and units. Which of the following is an example of using three significant figures?

• 5 moles of carbon

• 5.0 g of carbon

• 5.00 x 10^23 atoms of carbon

• 5.000 moles of carbon

What did Avogadro theorize in 1811?

• The volume of a gas is independent of temperature and pressure.

• The volume of a gas at a specific temperature and pressure contains equal numbers of atoms or molecules regardless of the nature of the gas.

• The volume of a gas decreases when the number of molecules increases.

• The behavior of gases is unpredictable and cannot be theorized.

What did Loschmidt estimate in 1865?

• The charge on an electron

• The average diameter of the molecules in air

• The number of electrons in a mole

• The volume of a given gas

What significant measurement did Millikan achieve in 1910?

• The average diameter of the molecules in air

• The number of particles in a given volume of gas

• The charge on an electron

• The volume of a given gas

How did Millikan obtain the Avogadro number?

• By estimating the average diameter of the molecules in air

• By measuring the volume of a given gas

• By dividing the charge on a mole of electrons by the charge on one electron

• By counting the number of particles in a given volume of gas

For what achievement did Perrin earn the Nobel Prize in 1926?

• For his work on the photoelectric effect

• For his contributions to quantum theory

• For his research on Avogadro's number

• For his discovery of the electron

What did Perrin name in honor of Avogadro?

• A unit of pressure

• A constant related to the number of molecules

• A new element

• A laboratory instrument

What is the proposed number of molecules in exactly 32-grams of oxygen according to Perrin?

• Avogadro's number

• Perrin's constant

• The atomic number of oxygen

• The molecular weight of oxygen

What isotope is used as the standard for the currently accepted definition of the mole?

• Hydrogen-1

• Carbon-12

• Oxygen-16

• Uranium-238