REVIEW How many particles are present in one

REVIEW

How many particles are present in one mole of particles?

If each image represents one mole of the substance pictured, which contains the greatest amount of substance?

A water molecule contains one central oxygen atom and two hydrogen atoms. How many oxygen atoms in 2. 2 moles of water?

Copper wire consists of copper atoms connected through metallic bonds. Find the moles of copper in 1. 87 x 1024 copper atoms.

Mass and The Mole

Medium, Large, and Extra Large • The size of the egg does not affect how many come in a carton.

A mole always contains the same number of particles but moles of different substances have different masses

Molar mass • mass in grams of one mole of any pure substance

Element’s molar mass = its atomic mass • Measured in units g/mol Carbon has an atomic mass of 12. 011 so the molar mass of Carbon is 12. 011 g/mol and 1 mole of Carbon has a mass of 12. 011 g

What is the molar mass of… • He • W • Cu • Na. Cl • H₂O₂

Using Molar Mass • You are selling jelly beans by the dozen at a candy sale. It takes too long to count out each dozen, so you decide to measure the jelly beans by mass. 1 dozen jelly beans = 35 g What should the mass be for 5 dozen jelly beans?

Moles to Mass • In a chemistry lab, you need 3. 00 mol of Copper for a chemical reaction. How do you measure that amount?

Moles to Mass 1. Find the atomic mass for the substance 2. Atomic mass = molar mass in g/mol 3. Multiply the molar mass by number of mol needed

Moles to Mass 1. Copper’s atomic mass = 63. 546 2. Atomic mass = molar mass in g/mol so copper’s molar mass is 63. 546 g/mol 3. Need 3 mol so 3 x 63. 546 = 191 g

Practice • Determine the mass in grams of each: • 3. 57 mol Al 3. 57 x 26. 982 = 96. 3 g • 2. 45 mol Si 2. 45 x 28. 086 = 68. 8 g

Mass to Moles • How many moles of Calcium are in 525 g Ca?

Mass to Moles 1. Find the atomic mass for the substance 2. Atomic mass = molar mass in g/mol 3. Divide total mass by the molar mass

Mass to Moles 1. Calcium’s atomic mass = 40. 078 2. Atomic mass = molar mass in g/mol so calcium’s molar mass is 40. 078 g/mol 3. Have 525 grams so 525/40. 078 is 13. 1 mol Ca

Practice • Determine the number of moles in each: • 25. 5 g Ag 25. 5 / 107. 868 = 0. 236 mol Ag • 300 g S 300 / 32. 066 = 9. 36 mol S

Converting Mass to # of Particles

Mass to # of Particles • You have 550 g of jelly beans left unsold. Without counting, how do you figure out how many jelly beans that is? 35 g = 1 dozen = 12

Mass to # of Particles Two Steps: 1. Convert Mass to moles 2. Convert moles to # of particles

How many atoms are in a gold coin with a mass of 31. 1 g? • Mass to moles • Moles to # of particles

If a neon bulb contains 2. 69 x 10²² atoms, what is the mass in grams? • # of particles to Moles • Moles to Mass

Mass 2. 5 g Au Moles 0. 0127 mol # of Particles 7. 64 x 10²¹ 4. 95 mol Zn 3. 95 x 10²³ atoms C 12. 5 mol Cu 8. 75 x 10²¹ atoms Sc 49. 6 g Se