Empirical Formula
Molecular Formula
Percent Composition of Elements
Basic Concepts
Stoichiometry and EF/MF conversions
100

a chemical formula of a compound that gives the proportions of the elements present in the compound

What is the empirical formula?

100

It tells us which atoms and how many of each type of atom are present in a molecule.

What is the molecular formula?

100

Percent composition of oxygen in CO2

What is 72.7%?

100

Law of conservation of mass

Mass cannot be created or destroyed in a chemical reaction, only rearranged.

100

Molar Mass of BaI

What is 391.138 g/mol?

200

What does the Empirical Formula tell us?

This formula tells us the simplest or most reduced ratio of elements in a compound.

200

How do we find the percent composition of an element?

The equation for percent composition is (mass of element/molecular mass) x 100.

200

Percent composition of nitrogen in NH3

What is 82.4%?

200

Avogadro's number

6.022 x 10^23 particles per mole.

200

Molar mass of NO

What is 30.01 g/mol?

300

What do we need to do to know the Moles of an atom?

We need to divide the grams of the element by the molar mass.

300

TRUE OR FALSE 

Does a molecular formula give us structural information?

False molecular formulas do not show how the atoms of the elements are bonded together.

300

Percent composition of Na in NaNO₂

What is 33.33%?

300

Difference between an atom and a molecule?

Why is an atom is the smallest component of an element whereas a molecule is made up of two or more atoms?

300

Empirical formula of C6H12O6

What is CH2O?

400

What does an empirical formula not tell you?


 The empirical formula does not show the actual number of atoms.

400

The formula that shows the number and kind of atoms which a substance of a molecule contained, is known as.


Chemical Formula

400

Percent Composition of CO3 in H2CO3

What is 96.75%?

400

Where do we find the Atomic mass of an Element? 

We find it in our periodic table!

400

Amount of moles in 7630 grams of MgS

What are 135.34 moles of MgS?

500

What is the empirical formula of a compound containing 60.0% sulfur and 40.0% oxygen by mass?

S3O4

500

Caffeine has the following composition: 49.48% of carbon, 5.19% of hydrogen, 16.48% of oxygen, and 28.85% of nitrogen. The molecular weight is 194.19 g/mol. Find out the molecular and empirical formula.

C4H5N2O.


500

Percent Composition of NO3 in Mg(NO3)2

What is 83.53%?

500

Difference between empirical and molecular formulas?

What is the empirical formula gives the lowest whole-number ratio of the elements in the compound, while the molecular formula gives the actual numbers of atoms of each element in the compound? (closest answer wins)

500

The molecular formula of a compound that has the empirical formula C2H4O, and its formula mass is 88 g.  

What is C4H8O2?

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