Molar mass - skylinecpchemistry

Transcript Molar mass - skylinecpchemistry

1 mole =

6.02 X 10

things This is called Avogadro’s number

Molar mass

Molar mass is the mass of a mole of that thing The molar mass of pennies is the mass of 6.02X10

23 pennies (about 2X10 24 grams) 2 million million million tons of pennies The molar mass of carbon is the mass of 6.02X10

23 carbon atoms (which happens to be exactly 12 grams)

Molar mass

The molar mass of: Ca = 40.08 grams MgCl 2 = 95.2 grams H 2 O = 18 grams (using the periodic table)

Moles

There are one mole of:

Atoms

in 40.08 grams of Ca (element)

Formula units

in 95.2 grams of MgCl 2 (ionic)

Molecules

in 18 grams of H 2 O (molecular) Remember that representative particles refer to the types of substances we are measuring

Moles

1 mole of atoms in 40.08 grams of Ca 3 moles of atoms in 95.2 grams of MgCl 2 3 moles of atoms in 18 grams of H 2 O This will come in handy when we study chemical reactions.

Moles

Gram atomic mass (GAM) refers to the mass of one mole of atoms of an element Gram molecular mass (GMM) refers to the mass of one mole of molecules of a compound Gram formula mass (GFM) refers to the mass of one mole of formula units of an ionic compound 6.02 X 10 23 remember this number

Name Strontium Formula Representative particle Element 1 Element 2 Element 3 Gram atomic mass (GAM) Sr atom Sr 87.6 g Iron Cobalt Silicon Aluminum

Name Formula Representative particle Element 1 Element 2 Element 3 Gram formula mass (GFM) Magnesium sulfate MgSO 4 Formula unit Mg S 4 O 123.3 g Potassium iodide Calcium sulfite Lithium oxide Beryllium fluoride

Name Formula Representative particle Element 1 Element 2 Element 3 Gram molecular mass (GMM) Carbon tetrachloride CCl 4 molecule C Cl 153.8 g Carbon monoxide Silicon dioxide Nitrogen Dihydrogen sulfide

How many moles in 26.8 grams of iron?

We are given on the left grams of iron, so that goes We want the right moles, so that must end up on Make conversion factors do that

How many moles in 26.8 grams of iron?

26.8 g Fe mole Fe 55.85 g Fe given Conversion factor

How many moles in 26.8 grams of iron?

26.8 g Fe mole Fe 55.85 g Fe Cancel units in numerator and denominator

How many moles in 26.8 grams of iron?

26.8 g Fe mole Fe 55.85 g Fe .48 mole Fe

We will need to be able to figure out how many grams are in a certain number of moles.

We use the same conversion factor as we just did, only inverted.

How many grams in .48 moles of iron?

.48 mol Fe 55.85 g Fe mol Fe given Conversion factor

How many grams in .48 moles of iron?

.48 mol Fe 55.85 g Fe Mol Fe Cancel units in numerator and denominator

How many grams in .48 moles of iron?

.48 mol Fe 55.85 g Fe mol Fe 26.8 g Fe

Conversion factors: 12 in / 1 ft 1 ft / 12 in 5280 ft / 1 mi 1 mi = 1.61 km 1 mi / 5280 ft 1.61 km / 1 mi

Conversion factors for calculating moles and grams:

12 g C / mol C Mol C / 12 g C 153.8 g CCl 4 / mol CCl 4 Mol CCl 4 / 153.8 g CCl 4 123.3 g MgSO 4 / mol MgSO 4 Mol MgSO 4 / 123.3 g MgSO 4

Things we’ll need to be able to do:

• Write chemical formulas from chemical names – Magnesium sulfate is MgSO 4 • Calculate molar mass from chemical formulas – 123.3 g MgSO 4 is one mole MgSO 4 • Use conversion factors to calculate moles from mass, and mass from moles – 123.3 g MgSO 4 / mol MgSO 4 – mol MgSO 4 / 123.3 g MgSO 4

How many grams in .06 mole potassium nitrate?

• Formula?

How many grams in .06 mole potassium nitrate?

• Formula?

• Molar mass?

How many grams in .06 mole potassium nitrate?

• Formula?

• Molar mass?

• Conversion factor?

How many grams in .06 mole potassium nitrate?

.06 mol KNO 3 101 g KNO 3 mol KNO 3 6.06 g KNO 3 given conversion factor

How many moles in 486 grams aluminum sulfate?

How many moles in 486 grams aluminum sulfite?

• Formula?

How many moles in 486 grams aluminum sulfite?

• Formula?

• Molar mass?

How many moles in 486 grams aluminum sulfite?

• Formula?

• Molar mass?

• Conversion factor?

How many moles in 486 grams aluminum sulfite?

486 g Al 2 (SO 3 ) 3 mol Al 2 (SO 3 ) 3 294 g Al 2 (SO 3 ) 3 1.65 mol Al 2 (SO 3 ) 3 given conversion factor

6.02 X 10 23 atoms of that element 1 mole of any element 1 molar mass of that element

How many molecules in 287 grams carbon dioxide?

• Formula?

How many molecules in 287 grams carbon dioxide?

• Formula?

• Molar mass?

How many molecules in 287 grams carbon dioxide?

• Formula?

• Molar mass?

• Conversion factor?

How many molecules in 287 grams carbon dioxide?

287 g CO 2 6.02 X 10 23 molecules CO 2 44 g CO 2 3.93 X10 24 molecules CO 2 given conversion factor

1. How many grams are in 2.73 moles of sodium chloride?

2. How many moles are in 682 grams of strontium nitrate?

3. How many representative particles are in .187 grams of copper(II) sulfate?

4. How many atoms are in 87.1 grams of magnesium chloride?

5. 239 grams of carbon tetrachloride is how many moles of molecules?