AP Chem Catalyst AP Chem Catalyst Catalyst Questions To Do & Homework

Conversion Factors To convert from one unit to another we use a conversion factor.

I. Conversion Factors Units You Want Units You Have Number with units given New number with New Units

Conversion Factors Example – Convert $15 to cents 100Cents 1 Dollars 15 Dollars 1500 ¢

Multi-Step Conversions We may need to take multiple steps to convert between units. We must set up a series of conversion factors so that all unnecessary units cancel one

Convert 3 hours to seconds 1 hour 3 hours 10,800 sec 60 min 1 min 60 sec

Table Talk How many days are there in 525,000 seconds? (Note – 1 day = 24 h, 1 h = 60 min, and 1 min = 60 s)

White Board Races

Question 1 Convert 500 minutes into seconds

Question 2 You have 5 dozen doughnuts, how many doughnuts do you have (12 doughnuts = 1 dozen)

Question 3 You have 14 cups of water, how many gallons of water do you have (1 gallon = 4 quarts; 1 quart = 4 cups)

Question 4 You have 32 cups of solution. How many gallons do you have? (1 gallon = 4 quarts; 1 quart = 4 cups)

Question 5 How many minutes are there in 1 year?

Question 6: 1.You have 42 dollars. You know the following conversions: 1 pound = $ pound = 1.25 Euro How many Euros do you have?

How High Can You Count? 602,200,000,000,000,000,00 0,000

Atoms, ions, and molecules are so small, that a grain of carbon may have over trillions of atoms/particles. to make counting large numbers easier, scientist use the mole.

What is the mole?

The Mole The mole is a unit that describes the amount of particles that a substance has. Just like 1 dozen = 12 eggs, 1 deck = 52 card: 1 mole = 6.02 x particles Avogadro’s Number

It’s a conversion factor! x particles mole

What does 1 mole look like?

He observed that The # of C atoms in exactly 12 grams of Carbon-12 had 6.02 x atoms, so he let 1 mole of any substance = 6.02 X particles/ions/atoms/compounds/ions How did Amedeo Avogadro come up with this conversion factor or relationship for counting particles?

Get it? 1 mole of C = 6.02 x C atoms 1 mole of H 2 O = 6.02 x H 2 O molecules 1 mole of Skittles = 6.02 x skittles 1 mole of electrons = 6.02 x electrons

What does 1 mole look like?

Example 1 How many atoms are there 2.66 moles of sulfur? Hint: You will be using avogadro’s number b/c you want # of particles (atoms).

Example 2 Find the # of molecules in 2.5 moles of sulfur dioxide (S0 2 )

What does all this mean? Don’t just do the math. 2.5 moles of SO 2 is like saying one dozen. 1 mole of any substance has X molecules 2.5 moles of SO 2 has 1.5 X molecules. Chemists can’t deal with 1.5 X molecules, it’s too large so we convert it into a smaller number.

Example 3 How many moles are in 2.54 X Fe 3+ cations?

You try these on line paper 4) How many ions are there in moles of Na+ cations? Answer: 1.13 X ions 5) How many atoms are there in 1.45 X moles of arsenic? Ans: 8.73 X 10 6 atoms 6) How many compounds in moles of acetic acid, C 2 H 4 O 2 ? Ans: 2.54 X acetic acid compounds 7) How many moles of xenon does 5.66 X atoms have? Ans: 0.94 moles of Xe 8) A sample of SO 2 has 3.01 X molecules, how many moles is this? Ans: 0.5 mol SO 2

Moles can be converted to mass

Molar Mass Molar mass is the mass, in grams, of 1 mole of substance. The molar mass is equal to the mass listed on the periodic table Units of Molar mass are g/mol Molar Mass Molar mass of carbon is 12 g / mol Means 1 mol of C has 12 grams

Example 9… What is the molar mass of Thorium? What does that mean?

Molar mass of Th = 232 g/ mol 1 mole of Th has 232 grams

You can find the mass from moles or # of particles Example 10: You have 2.44 X atoms of carbon whose molar mass is 12.01g/mol according to your PT. A)How many grams of carbon is that?

Example 11: Find the mass of each substance in grams: A)2.11 x atoms of copper

You try - Example 12: Find the mass of each substance in grams: 3.99 x molecules of methane, whose MM = 16 g/mol

Example 13: You find the molar mass of an element using the atomic mass but what if you have a compound like glycerol, C 3 H 8 O 3

You Try - Example 14: Use the answer from Ex 13 to find the amount of molecules in 47.5 g of glycerol.

Example 15: Find the molar mass of ZnCl 2

You try - Example 16: Find the molar mass of (NH 4 ) 2 SO 4

Exit Slip (10 min) A)Find the molar mass of toluene, C 6 H 5 CH 3. B)Find the # of moles in 7.51 g of toluene C)How many covalently bonded compounds are found in 5 grams of toluene?