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Counting Atoms. Co CO CO 2 C 6 H 12 O 6 Mg(NO 3 ) 2 How many atoms are there in 5 molecules of Mg(NO 3 ) 2 ? …5 molecules of C 6 H 12 O 6 ?. Bring: Calculator Periodic table EVERY DAY. Masses of atoms. Atoms are so tiny; how do we give their masses?
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Counting Atoms • Co • CO • CO2 • C6H12O6 • Mg(NO3)2 • How many atoms are there in 5 molecules of Mg(NO3)2? • …5 molecules of C6H12O6?
Bring: • Calculator • Periodic table • EVERY DAY
Masses of atoms • Atoms are so tiny; how do we give their masses? • Relative to (compared with) the mass of 6.02 x 1023 atoms of carbon-12 (which have a mass of 12 grams).
The mole • Mole: The SI unit for amount of substance (n) • Contains as many particles as there are atoms in 12 grams of carbon-12 • There are 6.02x1023 atoms in 12 grams of carbon-12 • Avogadro’s Constant = 6.02x1023
Molar Mass • The mole: 6.02 x 1023 particles of any substance • Ex: one mole of H2O is 6.022 x 1023 H2O molecules • Atomic mass is the mass in grams of one mole of an element(units: g/mol)
Find the atomic mass of… • Oxygen • Phosphorus • Sodium • Gold • Copper
Molar mass is a weighted average of all the isotopes of an element • Isotopes: atoms of the same element (same number of protons) with different numbers of neutrons. • mass number differs • how to calculate molar mass - later
Convert Between Moles and Number of Atoms Same two fractions for ANY element or compound!!
Scientific Notation on a calculator • 5.6 x 10-12 • Be sure to include any scientific notation from the calculator in your answer!! 5 6 . E 1 2 +/-
Convert 3.01 x 1023 atoms of silver to moles. • Convert 1.50 x 1012 atoms of lead to moles. • Convert 2500 molecules of water to moles. • Convert 2.05 x 1015 atoms of carbon dioxide to moles. • How many atoms of carbon are in 3.2 moles of carbon? • How many molecules of calcium chloride are in 1.0 mole of calcium chloride? • How many atoms of beryllium are in 2.1x1014 moles of beryllium? • How many molecules of ethene are in 6.11 moles of ethene?
How many molecules are there in 4.5 moles of H2O? • How many atoms are there in 4.5 moles of H2O?
Practice Moles to Number of Atoms Conversions • How many moles of vanadium are in 4.5 x 102 atoms of V? • How many moles of oxygen gas are in 45,000 molecules of O2? • How many moles of neon are in 1.2 x 103 atoms of Ne? • How many moles of chromium are in 7.90 x 1021 atoms of Cr?
Atoms to Moles • How many atoms of sodium are in 0.5 moles of sodium? • How many atoms of oxygen are in 1.5 moles of oxygen? • How many atoms of fluorine are in 0.075 moles of fluorine? • How many atoms of argon are in 3.45 moles of argon?
Converting between mass (g) and moles (mol) 1 mol O 15.999 g O • Or 15.999 g O 1 mol O • Choose one depending on if you are given grams of oxygen or moles of oxygen.
Lithium (Li) • Calculate the mass of 3.0 moles of lithium. • How many atoms are there in 3.0 moles of lithium?
Chromium (Cr) • Calculate the number of moles of chromium if you had 3.25x1034 atoms of chromium. • Calculate the mass of 3.25x1034 atoms of chromium.
Zinc (Zn) • How many moles of zinc are there in 34.7 grams of zinc? • How many atoms of zinc in 34.7 grams?
Write both fractions. • Germanium (Ge) • Calculate the mass of 3.0 moles of germanium. • How many atoms is that?
Which Fraction? • How many moles of chlorine are in 6.4 grams of chlorine?
Which Fraction? • How many grams of krypton are in 8.9x1012 moles of krypton? • How many atoms is that?
Which Fraction? • How many grams of hydrogen are in 32.1 atoms of hydrogen? • How many moles is that?
Which Fraction? • How many moles of aluminum are in 6.5 grams of aluminum?
Which Fraction? • What is the mass of 5.6x103 moles of mercury? • How many atoms is that?
Write both fractions. • How many moles are equal to 2.58x1067 atoms of Xenon (Xe)? • Calculate the mass.
Which Fraction? • How many moles of Xe are in 9.0 grams of Xe? • How many atoms is that?
Molar Mass Practice • What is the mass in grams of 3.50 mol of copper (Cu)? • What is the mass in grams of 2.25 mol of iron (Fe)? • What is the mass in grams of 0.375 mol of potassium (K)? • What is the mass in grams of 0.0135 mol of sodium (Na)? • What is the mass in grams of 16.3 mol of nickel (Ni)?
How many moles of Aluminum are in 11.9 grams of Aluminum? • How many moles of calcium (Ca) are in 5.00 grams of calcium? • How many moles of copper (Cu) are in 13.3 grams of Copper? • How many moles of gold (Au) are in 3.60 x 10-10 grams of gold?
Mass to atoms • What is the mass in grams of 1.20 x 108 atoms of copper? • What is the mass in grams of 7.5 x 1015 atoms of nickel? • How many atoms of sulfur are in 4.00 grams of sulfur? • How many atoms of carbon are in 1500 grams of carbon?