Law of Definite Proportions

The law of definite proportions states that a given chemical compound always contains the same _ in the exact same _ by mass.

• elements, compounds

• elements, molecules

• elements, proportions

• proportions, elements

Tags

NGSS.HS-PS1-7

The percentage of copper and oxygen in samples of “CuO” obtained by different methods were found to be the same. This illustrates the law of:

• Definite proportions

• Conservation of mass

• Multiple proportions

• Reciprocal proportions

The percent by mass formula used in the law of proportions is _.

• %m_e = 100% x m_e / m_c

• %m_e = m_e / m_c / 100%

• %m_e = m_e / (m_c x 100%)

• %m_e = m_c / m_e x 100%

Carbon 's mass is _.

• 6

• 12.01

• +/- 4

• 2

Tags

NGSS.HS-PS1-7

Oxygen's mass is _.

• 8

• 16

• -2

• 2

Tags

NGSS.HS-PS1-1

The mass of the compound CO₂ is _.

• 16

• 28.01

• 44.01

• 56.02

Tags

NGSS.HS-PS1-7

The percent by mass of carbon to oxygen in CO2 is _.

• 100%

• 33.3%

• 72.7%

• 27.3%

Tags

NGSS.HS-PS1-7

The working formula to calculate the mass of an element from the percent by mass of an element and the compound mass is _.

• m_e = (%m_e / m_c) x 100%

• m_e = (%m_e x 100%) / m_c

• m_e = 100% / m_c x %m_e

• m_e = m_c x %m_e / 100%

Tags

NGSS.HS-PS1-7

The mass of an unknown element would be _ if the percentage of it in a 44.01 g compound was 27.29%.

• 1.613 g

• 12.01 g

• 62.01 g

• 72.71%

Tags

NGSS.HS-PS1-7

The working formula to find the mass of a compound from the element mass and the percentage of that element is _.

• m_c = m_e / (%m_e x 100%)

• m_c = 100% x m_e / %m_e

• m_c = 100% / m_e / %m_e

• m_c = 100% x %m_e / m_e

Tags

NGSS.HS-PS1-7