Finding Percents and Percent of Proportion

Which law is used to calculate the percent composition of a compound?

• Law of conservation of mass

• Law of definite proportions

• Law of multiple proportions

• Avogadro's law

Tags

NGSS.HS-PS1-7

Which of the following is an example of a percent proportion in biology?

• The percentage of oxygen in the atmosphere

• The ratio of red blood cells to white blood cells

• The percentage of water in the human body

• The ratio of nitrogen to oxygen in the air

A solution is made by dissolving 10g of salt in 90g of water. What is the percent concentration of salt in the solution?

• 10%

• 11%

• 9%

• 12%

In a mixture of gases, the proportion of nitrogen is 78%. What is this an example of?

• Percent by volume

• Percent by mass

• Mole fraction

• Partial pressure

What is the percent by mass of oxygen in hydrogen peroxide (H2O2)?

• 47.1%

• 52.9%

• 94.1%

• 100%

Find the percent composition of CaCl₂?

• Ca: 36.11%; Cl: 63.88%

• Ca: 53.12%; Cl: 100%

• Ca: 36.11%; Cl: 83.56%

• Ca: 46.11%; Cl: 63.88%

What is the percent by mass of sodium in NaCl?

• 39%

• 61%

• 35%

• 65%

the ratio of the mass of each element to the total mass of the compound, expressed as a percent (%)

• element

• law of multiple proportions

• law of definite proportions

• percent by mass

Tags

NGSS.HS-PS1-7

The ratio of the number of atoms of each element in a compound to the total number of atoms, expressed as a percent (%)

• mole ratio

• law of definite proportions

• percent composition

• atomic number

The percentage by mass of each element in a compound

• molar mass

• percent composition

• empirical formula

• molecular formula