The Mole Concept

It is the standard scientific unit for measuring the amount of substance or large quantities of very small entities e.g. atoms, molecules, or other specified particles.

• Mole

• Molecule

• Atomic Mass

• Molar Mass

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The molecular formula for a carbon and hydrogen compound is C₈H₁₈. What is the empirical formula?

• C₈H₁₈

• C₁₈H₈

• C₉H₄

• C₄H₉

Which of the following statements regarding the mole is incorrect?

• A mole is a counting unit equal to 6.02 x 10²³ particles.

• A mole of particles of an element is numerically equal to the atomic mass of the element.

• The number of particles in a mole is known as Avogadro’s number.

• none of the above

Which of the following compounds is correctly matched with its empirical formula?

• dihydrogen dioxide -H₂O₂

• tetrahydrogen dioxide- H₄O₂

• hydrogen dioxide - H₂O

• dihydrogen dioxide- HO

Acetone, C₃H₆O, is the main component of fingernail polish remover. What is the molar mass of acetone to the nearest hundredths place?

• 29.018 g/mol

• 58.1 g/mol

• 34.058 g/mol

• 58.08 g/mol

What is the percent composition of hydrogen in water?

• 88.8%

• 66.7%

• 11.2%

• 33.3%

It shows the actual number of atoms of each element in a molecule.

• Molecular Formula

• Empirical Formula

• Chemical Formula

• Molar Formula

Chalk is mostly made of calcium carbonate, CaCO₃. If it took 48.6 g of chalk to write your name on the sidewalk, how many moles of calcium carbonate does your name contain?

• 0.486 mol

• 1.40 mol

• 0.714 mol

• 2.06 mol

Methyl acetate, is a solvent commonly used in paints, ink, and adhesives, and is often identified by the formula CH₃COOCH₃. What is the empirical formula for methyl acetate?

• CH₂O

• C₃H₆O₂

• C₆H₁₂O₆

• C_1.5H₃O

Ammonium nitrate (NH₄NO₃), commonly known as ANFO, is a compound used to make explosive devices. How many grams are in one mole of ammonium nitrate to the nearest thousandths place?

• 31.014 g

• 48.045 g

• 45.021 g

• 80.043 g