Counting Atoms Molar Mass and Percent Composition

How to calculate molar mass of H₂O?

• 2+16=18
• 1+16=17
• 2+32=34
• 1+31=32

What is the molar mass of CO₂?

• 12 g/mol

• 16 g/mol

• 32 g/mol

• 44 g/mol

Find the percentage composition of Mg in Mg₃(PO₄)₂.

• 27.48% Mg

• 43.11% Mg

• 16.00% Mg

• 12.63% Mg

What is the molar mass of table salt (NaCl)?

• 116.886 g/mol
• 35.453 g/mol
• 22.990 g/mol
• 58.443 g/mol

Which of the following is NOT needed to calculate percent composition?

• Mass of specific element
• Molar Mass
• Avogadro's Number
• Division

Calculate the molar mass of Ba(C₂H₃O₂)₂

• 255.3 g/mol

• 237.3 g/mol

• 228.3 g/mol

• 196.3 g/mol

What is the percent by mass of sodium in NaCl?

• 39%
• 61%
• 35%
• 65%

What is the mass percentage of Carbon in Carbon dioxide (CO₂)?

• 27.27%

• 42.86%

• 72.73%

• 72.72%

What are the units in molar mass?

• grams
• moles
• moles/gram
• grams/mole

Tags

NGSS.HS-PS1-7

The molar mass of an element is equal to its...

• Atomic mass
• Atomic number
• Oxidation number
• Valence electrons