Determining Mass Percents in Compounds

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

Tags

NGSS.HS-PS1-7

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

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%

Tags

NGSS.HS-PS1-7

The mass % of aluminum in aluminum sulfate Al₂(SO₄)₃ is:

• 12.93%

• 45.70%

• 7.89%

• 35.94%

• 15.77%

The mass % of H in methane (CH₄) is:

• 75%

• 92%

• 25%

• 4%

• 6%

• 5.60%

• 11.20%

• 88.79%

• 18.02%

Tags

NGSS.HS-PS1-7