Percent Composition/ Empirical and Molecular Formulas

What is Percent Composition?

• The percent by mass of each element present in a compound
• The simplest integer ratio of atoms in a compound
• It is to show the number of atoms in one molecule 

How do you determine the percent composition?

• By knowing the empirical formula
• By knowing the molecular formula
• By knowing the mass of the element and the molar mass of the compound.

What is the the empirical formula?

• To show the number of atoms in one molecule of a compound.
• It is the simplest integer ratio of atoms in a compound.
• It is the percent by mass of each element present in a compound. 

What are the steps to finding the empirical formula?

• 1. Convert grams to moles 2.divide by the least number of moles. 3. change percentage to grams 4. multiply until whole.
• 1. divide by the least number of moles. 2.multiply until whole. 3.change percentage to grams 4. convert grams to moles.
• 1. change percentage to grams 2. convert grams to moles. 3. divide by the least number of moles. 4. multiply until whole
• 1. multiply until whole 2. divide by the least number of moles 3. convert gram to mole. 4. change percentage to grams

What is the purpose of the molecular formula? 

• It is to show the number of atoms in one molecule of a compound.
• to find the percent by mass of each element present in a compound
• it is to find the simplest integer ratio of atoms in a compound.

What is the purpose of the molecular formula? 

• It is to show the number of atoms in one molecule of a compound.
• to find the percent by mass of each element present in a compound
• it is to find the simplest integer ratio of atoms in a compound.

What is the molecular formula?

• E= hv
• 14= pH+pOH
• molecular-formula mass/ simplest- formula mass    = X
• PV= nRT

Whats the empirical formula of a molecule containing 18.7% of Lithium, 16.3% of Carbon and 65.0% of oxygen?

• CO2Li3
• Li2CO3
• Li3CO2
• LiCO5

What is the molecular formula of a compound with an empirical formula of C2OH4 and a molar mass of 88 grams per mole?

• C2O4H8
• C8O2H4
• C4O2H8
• C4O8H2

Tags

NGSS.HS-PS1-7

Find the percent composition of N2S2.

• N: 69.6 S: 30.4
• N:36 S: 75.6
• N: 96.6 S: 3.4
• N: 30.4 S: 69.6

Tags

NGSS.HS-PS1-2