Percent Comp and Empirical Formula Test

A formula with the lowest whole # ratio of elements in a compound is called

• Molecular Formula
• Chemical Formula
• Empirical Formula 
• Distance Formula

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

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

An empirical formula:

• is a formula that calculates the coefficients of a compound in a balanced equation.
• is the simplest whole-number ratio of moles of elements in the compound.

What is the percent by mass of fluorine in CaF₂ (gram-formula mass = 78 g/mol)?

• 24%
• 49%
• 51%
• 65%

Which element has an abundance of 39.03% in the compound sodium phosphate, Na₃PO₄

• Na

• P

• O

• None of the above

Tags

NGSS.MS-PS1-1

What is the percent composition on Oxygen in NO₂? (rounded)

• 40%
• 50%
• 60%
• 70%

What is the percent composition by mass of sulfur in the compound MgSO₄ (gram formula mass = 120 g/mol)?

What is the percent by mass of sodium in NaCl?

Tags

NGSS.HS-PS1-7

Find the percent composition of Cu in CuBr₂ .   

What is the percent by mass of N in (NH₄)₂S?

• 47.1%

• 68.1%

• 44.1%

• 41.1%

Tags

NGSS.HS-PS1-7