Chemical Quantities: Introduction to the Mole Chapter 10

Essential Question: What is needed to complete problems using dimensional analysis? Please Place cell phones in cell phone caddy. Warm-Up: Pre-Lab Dimensional Analysis

Essential Question: What is a mole? Why is it used in chemistry? Please Place cell phones in cell phone caddy. Warm-Up: Chapter 10 Pre/Post Test

Why do we use moles? 1.Makes counting large numbers easier. 2.Helps us count the # of ions, atoms or molecules in a sample 3.Similar to using terms like: a dozen, a ream, a gross

What is meant by Avogadro’s Number? 1.The number of atoms of carbon in 12 grams of Carbon 12 2.In one mole of C 12 there are 6.02 X atoms X units/mole

How do we convert moles to particles? 1. You need the conversion factor: 1 mole = 6.02 X particles. 2. Begin with your given (circle it). 3. Use your conversion factor to change moles to particles by labeling all of your steps and crossing out units that cancel each other out. 4. Finish be ending with the unit you are being asked for (put a box around it).

5. How many ions are there in.187 moles of Na + ions?

6. How many atoms are there in 1.45 X moles of As?

How do we convert particles to moles? 1.You need the conversion factor: 6.02 X particles = 1 mole 2.Begin with your given (circle it). 3. Use your conversion factor to change particles to moles by labeling all of your steps and crossing out units that cancel each other out. 4. Finish be ending with the unit you are being asked for (put a box around it).

5. How many moles of Xenon do 5.66 X atoms equal?

2. How many moles of silver nitrate do 2.88 X 10 5 molecules equal?

Check-Out:  What is a mole?  Why is it used in chemistry?

Essential Question: How is the molar mass for an element and a compound determined? What is the relationship between molar mass and moles? Please Place cell phones in cell phone caddy. Warm-Up:

What is molar mass? 1.Molar mass is equal to the atomic mass or formula mass (if it is a compound) 2.Use g/mol 3.C= g/mol use the atomic mass from periodic table 4.CO 2 : C= 12 O = 16 x 2 or 32, therefore = 44 g/mol

How do we convert mass to moles to number of particles? 1. Calculate the molar mass of your atom or compound. 2. Begin with your given (circle it). 3. Use molar mass as your conversion factor to change mass to particles and don’t forget that 1 mole= 6.02 X particles 4. Label all your steps and cross out units that cancel each other out. 5. Finish be ending with the unit you are being asked for (put a box around it). * If you see grams in the problem you are going to need to calculate the molar mass.

6. How many moles are there in 237g Cu?

Check-Out:  How is the molar mass for an element and a compound determined?  What is the relationship between molar mass and moles?

Essential Question: What is STP? What is the relationship between moles and volume? Please Place cell phones in cell phone caddy. Warm-Up:

How do we calculate the volume of gas at STP? STP: Temp = 0 C or 273 KPressure= 1ATM or kPa Conversion Factor: 1 mole of a gas occupies 22.4 Liters at STP 1. What is the volume of 3.20 X mol of CO 2 at STP?

2. How many moles of H 2 in 6 liters?

Check-Out:  What is STP?  What is the relationship between moles and volume?

Essential Question: What is needed in order to determine percent composition? Please Place cell phones in cell phone caddy. Warm-Up:

How do you determine percent composition? 1.Percent composition is the percentage by mass of each element in the compound. 2.Molar mass is used to determine the simplest ratio or empirical formula

Check-Out:  What is needed in order to determine percent composition?

Essential Question: Are you test ready? Please Place cell phones in cell phone caddy. Warm-Up: Pre/Post Test

How do you use percent composition to determine the molecular formula? 1.Remember that the formula for an ionic compound is a ratio Ca 3 (PO 4 ) 2 3Ca: 2PO 4 2. For a molecular compound it is exact and the empirical formula is the molecular formula. 3. N (molar mass of empirical formula) = molar mass of a compound