moles —> mass
moles->particles
mass->particles
percent composition
empirical & molecular formulas
100

What is molar mass?

The amount of substance of any sample of a compound 

100

What is a particle?

Ions, atoms, & molecules 

100

How many molecules are in 450 grams of Na2SO4

1.91x10^24 molecules

100

Chemical formulas are the most direct way to represent the ___ ____ of a compound

Elemental makeup

100

What does an empirical formula show?

The proportions of elements present in a compound, but not the number arrangements of the atoms in the compound

200

How do you convert mass to moles?

By multiplying the atomic mass number with the given mole number

200

What is the number of particles in a mole called?

Avogadro’s number

200

How many molecules are in 24 grams of FeF3?

1.28x10^23 molecules

200

A 31.25 g sample of a gaseous compound containing only carbon and hydrogen was analyzed to show that it contained 23.44 g of carbon and 7.81 g of hydrogen. What is the percent composition of this compound?

75% Carbon; 25% Hydrogen

200

What is the empirical formula ratio?

1:2

300

Convert 15 grams of H2SO4 to moles

0.15 moles

300

How many moles are in 1.00 moles of He?

6.02x10^23

300

How many grams are there in 2.3x10^24 atoms of silver?

421 grams of silver

300
What is an alternate way to calculate the mass percent composition of a compound from its ___ ___

Molar Mass

300

A compound is composed of 52.14% Carbon, 13.13% Hydrogen, & 34.73% Oxygen by mass. What is the empirical formula?

C2H6O1

400

How many moles are in 15g of lithium?

2.2 moles of Li

400

How many atoms are in 1.50 moles of Hg?

9.03x10^23

400

How many grams are in 7.4x10^23 molecules of AgNO3?

208.98 grams

400

What is the molar mass of NaCl?

58.44 g/mol

400

What are the steps to convert from molecular to empirical formula?

1. Calculate the empirical formula mass

2. Divide the molecular mass by the empirical formula mass?

3. Multiply each subscript in the empirical formula mass

500

How many atoms are present in 2.5 moles of Silicon?

1.5 x 10^24 atoms

500

How many moles are in 2.91x10^22 atoms of He?

4.83x10^-2

500

How do you convert from mass to particle?

Use Avogadro’s number and set up an equation

500

What is the percent composition of sodium bromide?

Na 22.3%; Br 77.7%

500
What are the steps to calculating empirical formula?

1. Change % to grams

2. Convert g—>mol

3. Divide by smallest number of moles

4. Multiply to get a whole number

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