% Composition and Formulas

Percent Composition

100

What is the percent composition of lithium in lithium oxide (Li₂O)?

Molar Mass of Li₂O= 29.8g/mol

Percent Composition:46.3%

200

Calculate the percent composition of carbon in carbon dioxide (CO₂). 

Percent Composition: 27.27%

300

Calculate the percent composition of phosphorus in magnesium phosphate Mg₃(PO₄)_2. 

Percent composition: 23.58%

400

Calculate the percent composition of oxygen in magnesium hydroxide. Mg(OH)2

Percent Composition: 54.89%

500

Calculate the percent composition of both carbon and hydrogen in acetamide (C₂H₅NO).

Percent composition for C: 40.668%

Percent composition for H: 8.533%

Empirical Formula

100

Given that a 95.2g sample contains 40.8g of carbon and 54.4g of Oxygen, determine the empirical formula.

Empirical Formula:

CO

200

Calculate the empirical formula of a compound that is 85.6% Carbon, and 14.4% Hydrogen.

Correct Answer:

CH₂

300

Determine the Empirical Formula for a lactic acid that is 40.0% Carbon, 6.71% hydrogen, and 53.3% Oxygen. 

Empirical Formula

CH₂O

400

Write the empirical for a compound that is 21.20% Nitrogen, 6.06% Hydrogen, 24.30% Sulfur, and 48.45% Oxygen.

Empirical Formula: 

N₂H₈SO₄

500

A compound has 40.68% carbon, 5.12% hydrogen, and 54.20% oxygen. Calculate the empirical formula 

Empirical Formula:

C₂H₃O₂

Molecular Formula

100

What is the molecular formula for a compound with an empirical formula of C₂OH₄ and a molar mass of 44 g/mol. 

Molecular Formula:

C₂OH₄

200

What is the molecular formula for a compound with an empirical formula of C₄H₄O and molar mass of 136 g/mol. 

Molecular Formula:

C₈H₈O₂

300

The empirical formula of a compound is CH₂, its molar mass is 56 g/mol. Given this, find the molecular formula for this compound. 

Molecular Formula:

C₄H₈

400

Find the molecular formula for a compound with an empirical formula of CFBrO and a molar mass of 254.7 g/mol.

Molecular Formula:

C₂F₂Br₂O₂

500

What is the molecular formula of a compound containing 65.5% carbon, 5.5% hydrogen, and 29.0% oxygen, and a molar mass of 110 grams/mole?

Molecular Formula: C₆H₆O₂

True or False

100

True or False

The molecular formula for a compound can be the same as or a multiple of the compound's empirical formula.

True!

200

True or False:

The multiplication factor for empirical to molecular is found by dividing the empirical formula mass by the experimental molar mass

False!

Experimental / empirical

300

True or False:

Ms. Corrothers was a substitute before becoming a teacher.

True!

400

The formula for finding percent composition is:

(m_{element /} m_{compound) x 100%}

True

500

True or False

The empirical formula will always be greater than the molecular formula. 

False😮

Random

100

When is the Unit 6 Exam?

Wednesday or Thursday next week

200

Your chemistry room number.

2222

300

What university did Ms. Corrothers attend?

Xavier University of LA

Mississippi University for Women

UTHealth

400

How many siblings does Ms. Corrothers have?

3

500

When is the last day of school?

May 31st