Chapter 7 Chemical quantities.notebook
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Chapter 7: Chemical QuantitiesCounting Units Counting terms are used to describe specific quantities. 1 dozen donuts = 12 donuts1 ream of paper = 500 sheets1 case = 24 cans
A Mole of Atoms A mole is a counting unit that contains6.02 x 1023 atoms of an element (Avogadro’s number).
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A Mole of Sulfur 1 mole of sulfur contains Avogadro’s number of atoms.
A Mole of a CompoundA mole • of a covalent compound has Avogadro’s number of molecules.
• of an ionic compound contains Avogadro’s number of formula units.
Chapter 7 Chemical quantities.notebook
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Number of Particles in One Mole
Avogadro’s Number as an EqualityAvogadro’s number (6.02 x 1023) can be written as an equality and two conversion factors.
Equality:
Conversion Factors:
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Using Avogadro’s Number in CalculationsHow many Cu atoms are in 0.50 mole of Cu? Step 1 State the given and needed quantities.
Analyze the Problem.
Step 2 Write a plan to convert moles to atoms or molecules.
moles of Cu atoms of Cu
Step 3 Use Avogadro’s number to write conversion factors.
Step 4 Set up the problem to calculate the number of particles.
Chapter 7 Chemical quantities.notebook
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Subscripts State Atoms and Moles
The subscripts in a formula give• the relationship of atoms in the formula and• the moles of each element in 1 mole of a compound.
Glucose
C6H12O6
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Calculating Moles of an ElementHow many O atoms are in 0.150 mole of aspirin, C9H8O4?
Step 1 State the given and needed quantities.
Analyze the Problem.
Step 2 Write a plan to convert moles of compound to moles and then atoms of an element
Moles of moles atoms
aspirin of O of O
Step 3 Write equalities and conversion factors using subscripts and Avogadro's number.
Step 4 Set up the problem to calculate atoms of O.
Mole Particles conversion
https://www.youtube.com/watch?v=hNjwTRN1SRc
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Molar MassMolar mass is • the mass of one mole of a
substance.• the number of grams that
equals the atomic mass of that element.
Molar mass is rounded to the tenths (0.1 g) place for use in this text.
Give the molar mass of the following elements.
1. K = ________
2. Sn = ________
3. Si = ________
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Molar Mass of CaCl2Analyze the Problem.
Step 1 Obtain the molar mass of each element.
Step 2 Multiply each molar mass by the number of moles (subscript) in the formula.
Step 3 Calculate the molar mass by adding the masses of the elements.
Molar Mass conversion
https://www.youtube.com/watch?v=guAbb_yBSfs
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OneMole Quantities
32.1 g 55.9 g 58.5 g 294.2 g 342.3 g
Conversion Factors from Molar MassMethane (CH4), known as natural gas, is used in gas stoves and gas heaters.
1 mole of CH4 = 16.0 g of CH4
The molar mass of methane can be written as conversion factors
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Converting Mass to MolesHow many moles are present in a 65.1 g sample of KCl?
Step 1 State the given and needed quantities.
Analyze the Problem.
Step 2 Write a plan to convert grams to moles.
grams of KCl moles of KCl
Step 3 Determine the molar mass and write conversion factors.
Step 4 Set up the problem to convert grams to moles.
Mole Mass conversion
https://www.youtube.com/watch?v=zWzA-T54pPI
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Converting Moles to MassCalcium carbonate, CaCO3 is found in antacid tablets. If we have a 0.320 mole sample of CaCO3, how many grams are present?
Step 1 State the given and needed quantities.
Analyze the Problem
Step 2 Write a plan to convert grams to moles.
moles of CaCO3 grams of CaCO3
Step 3 Determine the molar mass and write conversion factors.1 mole of CaCO3 = 100.1 g of CaCO3
Step 4 Set up the problem to convert moles to grams.
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Atoms, Molecules and Grams
How many atoms of Cu are present in 35.4 g of Cu?
35.4 g Cu 1 mol Cu 6.02 X 1023 atoms Cu 63.5 g Cu 1 mole Cu
= 3.4 X 1023 atoms Cu
1. How many atoms of K are present in 78.4 g of K?
2. What is the mass (in grams) of 1.20 X 1024 molecules of glucose (C6H12 O6 )?
Mole conversion
https://www.youtube.com/watch?v=FmxkOJXIODM
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How many atoms of O are present in 78.1 g of oxygen gas O2 ?
78.1 g O2 1 mol O2 6.02 X 1023 molecules O2 2 atoms O 32.0 g O2 1 mol O2 1 molecule O2
How many atoms of C are present in 90.1 g of of glucose (C6H12 O6 )?
How many atoms of H are present in 90.1 g of of glucose (C6H12 O6 )?
How many atoms of O are present in 90.1 g of of glucose (C6H12 O6 )?
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Percent Composition of Compounds • Percent composition consists of the mass percent of each element in a compound:
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Practice: The odor of pears is due to the organic compound called propyl acetate which has the formula C5H10O2. What is the mass percent composition of each element?
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Connections between Mass, Moles, and Particles
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