Chapter 10 Chemical Quantities The MOLE

What is a mole? A) A blind furry animal. B) A brown mark on your body. C) An important Chemistry concept. D) All of these.

As you may have guessed, D is the correct answer!! Although a mole might be cute and fuzzy, we are going to focus on the Chemistry concept.

A mole is a counting unit. Just like: 12 eggs equals a dozen eggs 144 pencils equals one gross of pencils 60 seconds equals one minute 500 sheets of paper equals one ream

One mole equals x particles So one mole of eggs would be x eggs One mole of pencils would be x pencils And so on...

Where did the mole come from? The unit, called the mole (or mol), is defined as the number of atoms in exactly 12g of the carbon-12 isotope The number of particles in one mole, x 10 23, is known as Avogadro’s constant or number. This was named after Amedeo Avogadro ( ) whose ideas were crucial to the early development in Chemistry

Amadeo Avogadro

6.022 x is a very large number! If we did not use scientific notation to write out x 10 23, we would write out 6022 with 20 zeros after it.

602,200,000,000,000,00 0,000,000 Wow that is a BIG number!!

Imagine that we had a mole of gumballs. If all 6 billion people on Earth were to do nothing but count the gumballs in one mole at the rate of one gumball per second, it would take over 3 million years to count all the gumballs!! See pg. 316 for more

What is all of this used for? Avogadro’s constant can be used to convert an amount of moles into the equivalent number of atoms or grams.

Mole Problem Solving Strategy Example: How many eggs are in 8 dozen?

This strategy can also be used with the mole concept. How many atoms are in 3.5 moles of copper?

convert from atoms to moles How many moles are in 3.01 x atoms of Sodium?

1. How many atoms are present in 2.25 moles CO 2 ? 2. How many oxygen atoms are in 5.2 mol of water? 3. Find the molar mass of Cu(NO 3 ) 2 ? 4. What is the mass of 1.00 mol of Cu(NO 3 ) 2 ?

If you showed all the steps, the correct answers are: x atoms x atoms O g/mol g

some mole jokes! Who is Avogadro’s favorite actor? Mol Gibson…. Ha ha! Where did Avogadro go on Saturday? The shopping mole. What did Avogadro have on his pancakes? Molasses!! (I know you may think these jokes are remolting, but you will grow to love them!!)

One more joke Why did Avogadro look forward to the year 2000? It was the start of the new molennium!!!

Sec Homework: Q’s pg How many moles is 2.80 x atoms Si? 4. How many moles is 2.17 x representative particles Br?

Q’s pg How many atoms are in 1.14 mol SO 3 ? 6. How many carbon atoms are in 2.12 mol C 3 H 8 ? How many H atoms are in 2.12 mol C 3 H 8 ?

Q’s pg Find the molar mass of PCl 3 ? 8. What is the mass of 1.00 mol NaHCO 3 ?

Q’s pg. 315 Lesson check Calculate If a dozen apples has a mass of 2.0 kg and.20 bushel is 1 dz apples, how many bushels of apples are in 1.0 kg of apples? 13. How many moles is 1.50 x molecules of NH 3 ?

Pg. 315 continued 14. How many atoms are in 1.75 mol of CHCl 3 ? 15. What is the molar mass of CaSO 4 ?

Ch 10 section 2 : Mole – Mass relationships Find the number of moles in 25.6 g of Na 2 SO 4.

Calculate the mass in grams of 3.50 moles of iron(III) sulfate.

Mole-Volume relationship Avogadro’s hypothesis states that equal volumes of gases at the same temperature and pressure contain equal numbers of particles. Note: volume of a gas varies with a change in Temp. and pressure

Standard temperature and pressure (STP) means a temperature of 0 0 C and a pressure of 1 atmosphere (atm). For any gas: 1 mol = 22.4 L = 6.02 x 10 23

What is the volume of mol nitrogen gas?

How many moles are in L of Neon?

Molar mass and density The density of a gas is g/L at STP. What is the molar mass of the gas?

Ch 10 section 3 Percent Composition of a compound: Fe 2 (SO 4 ) 3

Calculate mass of element in a compound Calculate the mass of iron in 57.2 g Fe 2 (SO 4 ) 3. Hint: use % comp. from previous question.

Empirical Formulas Empirical Formula (simplest formula) – lowest whole number ratio of atoms in a compound. EX./ Given:71.72 % Cl, 16.16% O and % C. Calculate empirical formula.

Molecular Formulas Determine the molecular formula for a compound that is 94.1% O and 5.9 % H with a molar mass of 34 g/mol.