moles  # of particles moles  mass MOLE (4.4) Calculations Involving the

Molar Mass (M) Avogadro’s number (N A ) Mole (n)

By the end of the lesson you will be able to....  convert mass to moles and vice versa  convert moles to number of particles and vice versa  convert mass to number of particles and vice versa

dimensional analysis is utilized in many subjects. to measure distances, we convert between meters and kilometers to follow recipes, we convert between cups and tablespoons the conversion factors utilized in chemistry are specific to the language of chemistry

when substances react, they do so in simple ratios of moles. However, in the lab, balances give readings in grams this is one of the many reasons why we need to understand how to convert grams to moles and moles to grams

Aluminum is often used for the structure of light-weight bicycle frames. How many grams of Al are in 3.00 moles of Al? 3.00 moles Al ? g Al ( to convert between mass and moles or vice versa, you need the molar mass)

1. Molar mass of Al1 mole Al = 27.0 g Al 2. Conversion factors for Al 27.0g Al or 1 mol Al 1 mol Al 27.0 g Al 3. Setupm = 3.00 moles Al x 27.0 g Al 1 mole Al Answer m = 81.0 g Al

The artificial sweetener aspartame (Nutra-Sweet), formula C 14 H 18 N 2 O 5, is used to sweeten diet foods, coffee and soft drinks. How many moles of aspartame are present in 225 g of aspartame? 1. Molar mass of aspartame M = (14)(12.01g/mol) + (18)(1.01g/mol) + (2) (14.01g/mol) + (5)(16.00g/mol) =294.34g/mol 2. Conversion factors for aspartame g aspartame or 1 mol aspartame 1 mol aspartame g aspartame

The artificial sweetener aspartame (Nutra-Sweet), formula C 14 H 18 N 2 O 5, is used to sweeten diet foods, coffee and soft drinks. How many moles of aspartame are present in 225 g of aspartame? 3. Setup n = 225 g aspartame x 1 mol aspartame g aspartame Answer n = mol aspartame

moles (n) = mass (m) molar mass (M) mass(m) = moles(n) x molar mass (M)

How many molecules are in 3.50 mol of table sugar, sucrose? 1. Avogadro’s #N A = 6.02 X molecules/mol 2. Conversion factors 6.02 X molecules or 1 mol 1 mol 6.02 X molecules 3. SetupN = 3.50 mol sugar x 6.02 X molecules 1 mol sugar Answer N = 2.11 X molecules of sugar

How many molecules are present in 2.0 mol of carbon dioxide? How many atoms are present? N = 2.0 mol X 6.02 X molecules mol = 1.2 X molecules CO 2 # of atoms = # of molecules X # of atoms molecule = 1.2 X molecules CO 2 X 3 atoms 1 molecule CO 2 = 3.6 X atoms

How many moles are in 2.40 X formula units of table salt, NaCl? 1. Avogadro’s #N A = 6.02 X formula units/mol 2. Conversion factors 6.02 X formula units or 1 mol 1 mol 6.02 X formula units 3. Setup n = 2.40 X form. units x 1 mol 6.02 X form. units Answer n = mol NaCl

moles (n) = # of particles (N) Avogadro’s # (N A ) # of particles (N) = moles(n) x Avogadro’s # (N A )

What is the mass (in grams) of 1.20 X molecules of glucose (C 6 H 12 O 6 )? 1. Calculate the moles n = 1.20 X molecules X 1 mol 6.02 X molecules = 1.99 mol 2. Calculate the molar mass of glucose M = (6)(12.01) + (12)(1.01) + (6)(16.00) g/mol = g/mol

What is the mass (in grams) of 1.20 X molecules of glucose (C 6 H 12 O 6 )? 3. Calculate the mass of glucose m = 1.99 mol X g 1 mol = 3.59 X 10 2 g

molar mass Avogadro’s number mass (g) moles (mol) # particles Everything must go through Moles!!! A Summary

NOW IT’S YOUR TURN!! TRY SOME PROBLEMS USING THE STEPS SHOWN HERE. THE MORE YOU DO THE EASIER THEY GET!!!!