Review Set 3 - Moles & Chemical Formulas

Multiple Choice

What is the value of Avogadro's number?

• 6.02 x 10²³

• 1.00 x 10⁶

• 3.14 x 10⁸

• 9.81 x 10²

Multiple Choice

How many atoms is 0.0825 moles of Silver?

• 0.0825 atoms

• 4.97 x10²² atoms

• 4.97 x10²³ atoms

• 1.37 x10²⁴ atoms

Multiple Choice

How many moles are in 8.30 X 10²³ molecules of H₂O?

• 1.38 X 10²³ moles H₂O

• 1.38 moles H₂O

• 2 moles H₂O

• 1 mole H₂O

Drag and Drop

Avogadro's number tells us ​

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. This number is ​

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. In order change the number of molecules into the number of moles we use the number of molecules ​ ​

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Avogadro's number. If we want to go the opposite direction and change the number of moles to the number of molecules, we use the number of moles ​

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Avogadro's number.

Drag these tiles and drop them in the correct blank above

the number of particles in a mole

6.022 x 10^23

divided by

multiplied by

Multiple Choice

What is the molar mass of CO₂?

• 44.01 g/mol

• 32.00 g/mol

• 28.01 g/mol

• 12.01 g/mol

Multiple Choice

Calculate the molar mass for Al(OH)₃

• 78.0 g/mol

• 72 g/mol

• 28 g/mol

• 25 g/mol

Multiple Choice

What is the molar mass of the diatomic element nitrogen?

• 7 g/mol

• 14 g/mol

• 28 g/mol

Multiple Choice

How many moles are in 16.94g of water?

• 16.94 mol H₂O
• 0.9401 mol H₂O
• 305.3 mol H₂O
• 1.063 mol H₂O

Multiple Choice

What is the percent by mass of magnesium in MgO?

• 20%
• 40%
• 50%
• 60%

Multiple Choice

What is the percent by mass of fluorine in CaF₂ ?

• 24%
• 49%
• 51%
• 65%

Multiple Select

Which of the following statements about empirical and molecular formulas are correct?

• The empirical formula shows the simplest whole number ratio of elements.

• The molecular formula is always a multiple of the empirical formula.

• Empirical and molecular formulas are always the same.

• The molecular formula shows the actual number of atoms of each element in a molecule.

Multiple Choice

What is the empirical formula if you have 81.82% carbon and 18.18% hydrogen?

• C₃H₈

• CH₄

• C₂H₂

• C₄H₁₀

Multiple Select

Which of the following pairs correctly matches an empirical formula with its corresponding molecular formula?

• NO₂ and N₂O₄

• C₂H₆O and C₆H₁₈O₃

• P₂O₅ and P₄O₁₁

• All of the above

Multiple Choice

LiBr is called

• lithium bromine

• lithium (I) bromine

• lithium bromide

• lithuim (I) bromide

Multiple Choice

What is the chemical formula of Iron(III) bromide made up of Fe⁺³ and Br^-?

• FeBr

• Fe(III)Br

• FeBr₃

• Fe₂Br₃

Multiple Choice

Disulfur trioxide

• S₃O₂
• SO
• S₂O₃
• S₂O

Multiple Choice

What is the name of CO

• Carbon oxide
• Carbon dioxide
• Carbon monoxide
• Carbon II oxide