140 likes | 263 Views
Mole 10. A frustration, a concept, a unit. Why?. Look at the two recipes. What is the same? What is different?. Early Chemistry. If you were given a pile of this chemical and a pile of that chemical how do you know how much to put into were? This is the issue of the early chemist.
E N D
Mole 10 A frustration, a concept, a unit
Why? Look at the two recipes. What is the same? What is different?
Early Chemistry • If you were given a pile of this chemical and a pile of that chemical how do you know how much to put into were? • This is the issue of the early chemist. • Compounds react, but why and how? • On an atomic view • C + O2 CO2 • 2H2 + O2 2H2O
How do we scale that up? • How do we go from atoms to something we can touch and measure? • Avogadro expanded on the theories around him • It theorized that the number of particles in an atom will be similar regardless of which element. • Avogadro’s number is based on the number of atoms in 12 grams of carbon-12.
Converting between Moles and Particles • 6.02 x 1023 is the number of particles in one mole • One mole is the same as saying • One dozen • One ream • One pair • These are all numbers that are associated with the label. • One dozen= 12 • One ream= 500 • One pair= 2
If you have one mole of lithium how many atoms do you have? • 6.02x1023 • If you have 3 moles of Fluorine how many atoms are there? • 1.81x1024 The math
3.92x1024 molecules of carbon dioxide gas will be how many moles? • 6.5 moles • How many moles of carbon are there in that problem? • 6.5 moles • How many moles of of oxygen are there? • 13 moles Setting up the conversion
Moles to grams Something we can measure
The idea of a mole • Avogadro based the number of atoms on the number of atoms found in 12 grams of carbon-12. • One mole is equal to the atomic weight of the substance in grams. • How many grams are in on mole of Phosphorus? • 31 grams • What is the mass of one mole of silver? • 108 grams
How many grams in 3.75 moles of Carbon? • 45 grams C • 4.05 moles of Zirconium has how much mass? • 368 grams Zr • How many moles are in 200 grams of Vanadium? • 3.92 moles V • How many moles are in 8 grams of Helium? • 2 moles He Mass to mole and mole to mass
Molar mass is the weight of a substance with one mole of the substance. • When dealing with elements this is easy. • Carbon is 12g • Oxygen is 16g • Hydrogen is 1g • And so on. • When we start talking about compound and molecules then we change it up. • Carbon dioxide • CO2 • C (14) + O (16)*2 Molar Mass
Calcium Oxide • 56 grams • Magnesium Iodide • 278 grams • Sodium Nitrate • 85 grams • Sodium Nitrite • 69 grams What is the Molar mass for… Practicing molar mass
Volume • Avogadro’s principle • All gases at the same temperature and pressure contain equal volumes must contain equal numbers of particle • One mole contains 6.02x1023 particles • Avogadro’s principle explains that it should take up the same amount of space. • 1 mole of a gas = 22.4 L of that gas
3.72L of He is how many moles? • 0.166 moles Helium • How many L would you have if you had 1.6 moles of Chlorine? • 35.8 L of Cl How much space?