CFA - Mole Conversions

Why do chemists use moles instead of actual masses of atoms?

• Atoms and molecules are too small to see under a microscope.
• Actual masses of atoms, molecules, and ions are too small to use in calculations.
• Moles help determine the density of an atom.
• Moles are used to identify isotopes of an element.

What is the symbol for a mole?

• mo
• ml
• mn
• mol

What is the symbol for mass?

• kg
• k
• g
• gs

Why is the mole used in chemistry?

• To measure the exact weight of an atom.
• To simplify calculations for large numbers of particles.
• To determine the density of a substance.
• To balance chemical equations automatically.

How many particles are in 1 mole of a substance?

• 6.02×10 to the power of 22
• 6.01×10 to the power of 23
• 6.02×10 to the power of 23
• 6.01×10 to the power of 22

If 4 moles of NaCl are present, what is the mass (in grams)? (Molar Mass of NaCl = 58.44 g/mol)

• 58.44 g
• 116.88 g
• 233.76 g
• 29.22 g

If a sample of CH₄ has a mass of 48.12 g, how many moles are present? (Molar Mass of CH₄ = 16.04 g/mol)

• 3.00 moles
• 0.33 moles
• 1.00 moles
• 2.35 moles

What is a relative atomic mass?

• The total number of protons and neutrons in the nucleus of an atom.
• The average mass of an atom of an element in atomic mass units.
• The combined mass of all the electrons in an atom’s structure.
• The measured weight of a molecule in grams per atomic unit.

Where can the relative atomic mass of an element be found?

• It is found next to the element’s symbol on the periodic table.
• It is written at the top of the element’s symbol on the periodic table.
• It is found under the element’s symbol on the periodic table.
• It is listed beside the element’s symbol on the periodic table.

How do you calculate the number of moles of a substance?

• Multiply the given mass by the molar mass.
• Divide the given mass by the molar mass.
• Add the given mass to the molar mass.
• Subtract the molar mass from the given mass.