Presentation on theme: "Chapter 6 Chemical Reactions and Quantities"— Presentation transcript:
1 Chapter 6 Chemical Reactions and Quantities 6.5 Molar Mass
2 Molar Mass The molar mass is the mass of one mole of a substance the atomic mass of an element expressed in grams
3 Learning Check Give the molar mass to the nearest 0.1 g. A. K = ________B. Sn = ________
4 Solution Give the molar mass to the nearest 0.1 g. A. K = 39.1 g B. Sn = g
5 Molar Mass of CaCl2For a compound, the molar mass is the sum of the molar masses of the elements in the formula. We calculate the molar mass of CaCl2 to the nearest 0.1 g as follows.ElementNumber of MolesAtomic MassTotal MassCa140.1 g/mole40.1 gCl235.5 g/mole71.0 gCaCl2111.1 g
6 Molar Mass of K3PO4 Determine the molar mass of K3PO4 to 0.1 g. K 3 ElementNumber of MolesAtomic MassTotal Mass in K3PO4K339.1 g/mole117.3 gP131.0 g/mole31.0 gO416.0 g/mole64.0 gK3PO4212.3 g
9 Learning CheckCalculate the molar mass for Al(OH)3 to the nearest 0.1g.1) g/mole2) g/mole3) g/mole
10 SolutionSTEP 1 Obtain the molar mass of each element Al g/mole O g/moleH g/moleSTEP 2 Multiply each by the subscript in the formula.1 mole Al x g Al = g1 mole Al3 moles O x g O = g1 mole O3 moles H x 1.0 g H = g1 mole HSTEP 3 Total: 1 mole of Al(OH)3 = g (3)
11 Learning CheckProzac, C17H18F3NO, is an antidepressant that inhibits the uptake of serotonin by the brain. What is the molar mass of Prozac?1) g/mole2) 262 g/mole3) 309 g/mole
12 Solution3) 309 g/moleSTEP 1 Obtain the molar mass of each element C g/mole H 1.0 g/moleF g/mole N 14.0 g/mole O 16.0 g/moleSTEP 2 Multiply each by the subscript in the formula.17 moles C x g C = g1 mole C18 moles H x 1.0 g H = g1 mole H
13 Solution (continued) STEP 2 (continued) 3 moles F x 19.0 g F = 57.0 g 1 mole F1 mole N x g N = g1 mole N1 mole O x g O = g1 mole OSTEP 3 Total: 1 mole of C17H18F3NO = g
14 Conversion Factors from Molar Mass Methane (CH4), known as natural gas, is used in gas stoves and gas heaters.1 mole of CH4 = g of CH4The molar mass of methane can be written as conversion factors.16.0 g CH and mole CH41 mole CH g CH4
15 Learning Check Acetic acid, C2H4O2, gives the sour taste to vinegar. Write an equality and two molar mass conversion factors for acetic acid.
16 Solution Acetic acid, C2H4O2, gives the sour taste to vinegar. Write an equality and two molar mass conversion factors for acetic acid.Equality:1 mole of acetic acid = g of acetic acidMolar mass conversion factors:1 mole acetic acid and g acetic acid60.0 g acetic acid mole acetic acid
18 Calculating Grams from Moles Aluminum is often used for the structure of lightweight bicycle frames. How many grams of Al are in 3.00 moles of Al?3.00 moles Al x g Al = g of Al1 mole Almole factor for Al
19 Learning CheckThe artificial sweetener aspartame (NutraSweet), C14H18N2O5 , is used to sweeten diet foods, coffee, and soft drinks. How many moles of aspartame are present in 225 g of aspartame?
20 Solution STEP 1 Given: 225 g of aspartame, C14H18N2O5 STEP 2 Plan: g of aspartame moles of aspartameSTEP 3 Determine molar mass of aspartame:14(12.0) + 18(1.0) + 2(14.0) + 5(16.0)= 294 g/moleSTEP 4 Set up problem to calculate the moles of aspartame:225 g aspartame x 1 mole aspartame294 g aspartamemole factor (inverted)= mole of aspartame
Your consent to our cookies if you continue to use this website.