N2K (08/30/17) The mass of a lump of gummy bears is 313.6g. If each gummy bear weighs 3.2g, how many gummy bears are in the lump? The mass of a copper cylinder is 49.71 grams. If the mass of one copper atom is 1.06 x 10-22 g, how many copper atoms are there in the cylinder?

Moles!!! August 30, 2017 Today’s Agenda: N2K/Word Wall Isotopes and Atomic Mass Exit Ticket 17. fallacy: an incorrect idea or belief.

N2K Solutions (08/30/17) The mass of a lump of gummy bears is 313.6g. If each gummy bear weighs 3.2g, how many gummy bears are in the lump? # 𝒐𝒇 𝒈𝒖𝒎𝒎𝒚 𝒃𝒆𝒂𝒓𝒔= 𝟑𝟏𝟑.𝟔 𝒈 𝟑.𝟐 𝒈 =𝟗𝟖 The mass of a copper cylinder is 49.71 grams. If the mass of one copper atom is 1.06 x 10-22 g, how many copper atoms are there in the cylinder? # 𝒐𝒇 𝑪𝒐𝒑𝒑𝒆𝒓 𝒂𝒕𝒐𝒎𝒔= 𝟒𝟗.𝟕𝟏𝒈 𝟏.𝟎𝟔 𝒙 𝟏𝟎 −𝟐𝟐 𝒈 =𝟒.𝟔𝟗 𝒙 𝟏𝟎 𝟐𝟑

Counting Atoms and the Mole The Moley Mole!!!

Counting Atoms SI unit for an amount of substance is called mole. A mole measures the number of particles within a substance. A mole refers to a specific number of particles. (Counting Unit) How many eggs are in a dozen?

1 mole = 6.02 x 1023 particles (a particle can be anything) 6.02 x 1023 is also known as Avogadro’s Number 1 mole magnesium = 6.02 x 1023 Mg atoms 1 mole zinc = 6.02 x 1023 Zn atoms 1 mole lead = 6.02 x 1023 Pb atoms 1 mole of Au = ? 1 mole of tacos = ? 1 mole of dollars = ?

Molar Mass Although 1 mole always contains the same number of particles, the mass of one mole varies depending on the substance. Molar Mass – mass of one mole of a substance. Mass of one mole of an element is equal to its ATOMIC MASS expressed in grams. 1 mole of magnesium = 24.31 grams 1 mole of zinc = 65.39 grams 1 mole of lead = 207.2 grams 1 mole of lead = 65.39 grams

O Periodic Table Oxygen 8 Average Atomic Mass: Molar Mass: Tells us BOTH the average mass of all isotopes(AMU) AND Mass of 1 mole of the substance (g/mole) 15.999

Molar Mass What is the molar mass of oxygen? 15.999 g/mol or 16.0 g/mol Rounding to the tenths place is the best practice. What is the molar mass of sodium? 22.990 g/mol or 23.0 g/mol What is the molar mass of Chlorine? 35.453 g/mol or 35.5 g/mol

Molar Mass What is the molar mass of CO (Carbon Monoxide)? (I’ll help with this one. Look to the board and the answer shall appear!). What is the molar mass of H2O? Now it’s your turn. We’ll check it together.

Mole Conversions Many times in chemistry, you will need to express a measurement in a unit different from the one given or measured initially. Conversion factor = ratio of equivalent measurements used to convert from one unit to another. (take form of a fraction) 12 in = 1 ft  and Write the conversion factor for the number of seconds in one minute

Quick Example Example: How many inches are in 2 feet? If the same unit is on the top and bottom of a fraction, they cancel each other out Example: How many inches are in 2 feet? 𝟐 𝒇𝒕 𝒙 𝟏𝟐 𝒊𝒏 𝟏 𝒇𝒕 = 𝟐 𝒇𝒕 𝒙 𝟏𝟐 𝒊𝒏 𝟏 𝒇𝒕 =𝟐𝟒 𝒊𝒏

Don’t forget units: Unit you want Unit you’ve got How to convert: Write the # you are given and its UNIT! Write a x ------------- (fraction bar) Write the unit you started with on the BOTTOM Write the unit you want on the TOP. Write the number that goes with each of your UNITS next to the correct unit. Multiply the top and press enter. Then divide by the bottom.

Example: How many kilometers are in 84 miles? (1 km = 0.6 mi) How to convert: Write the # you are given and its UNIT! Write a x ------------- (fraction bar) Write the unit you started with on the BOTTOM Write the unit you want on the TOP. Write the number that goes with each of your UNITS next to the correct unit.\ Multiply the top and press enter. Then divide by the bottom. Example: How many kilometers are in 84 miles? (1 km = 0.6 mi) 84 mi x 1 km = 140 km 0.6 mi

Number Used in Conversion Factor Molar Mass (Atomic Mass) Mole Conversions Many times in chemistry, you will need to express a measurement in a unit different from the one given or measured initially. Conversion factor = ratio of equivalent measurements used to convert from one unit to another. (take form of a fraction) 1mole = 6.02x1023 = molar mass (from PT) Label Number Used in Conversion Factor Mole 1 Atoms 6.02 x 1023 Mass (grams) Molar Mass (Atomic Mass)

Mole Conversion Problems A chemist produced 78.2 g of potassium. How many moles of potassium were produced? How many nitrogen atoms are contained in 0.550 mol N? Calculate the mass, in grams, of 2.07 x 1024 atoms of bromine.

Mole Conversion Practice Key Carefully read the problem Write what you are told to start with. Make a “x” and “_____” to put the conversion factor in. Write the unit from the top on the bottom and desired unit on top. Fill in correct numbers. Do math. Profit.

Mole Conversion Practice Remember: 1 mole X = An atoms X = # grams X 0.1395 mol F 3.93 x 10^24 atoms Cl 8.12g Co 14.10 mol O 3.37g Ar 3.93 x 10^23 atoms Al 163.53g S 3.913 x 10^23 atoms Ag 0.463 mol Mg Instructions If you are given mol, find # of atoms and grams If you are given # of atoms, find mol and grams If you are given grams, find mol and # of atoms