1. Topics Physical vs chemical Extensive vs Intensive Units of measure
Dimensional analysis and significant figures
Chapters 1-3 Lesson 6

2. Problems & 2.116
Classify each of the following as a compound, a homogeneous mixture, or a heterogeneous mixture
Distilled water orange juice
Gasoline vegetable soup
Beach sand cement
Wine calcium sulfate
Air tea
Chapters 1-3 Lesson 6

3. Problems 2.115 & 2.116 homogeneous mixture Gasoline Wine Air Tea
heterogeneous mixture
Beach sand orange juice
cement vegetable soup
compound
Distilled water calcium sulfate
Chapters 1-3 Lesson 6

4. 1-80
Carry out the following calculation, and report the answer with the correct number of significant figures.
(1.68) – 2.3
1.248 X 103
Chapters 1-3 Lesson 6

5. What is the price of 325 cm of wire if the wire costs $0.15/ft?
Chemical Problem Solving: A Systematic Approach to Solving Chemistry Problems
What is the price of 325 cm of wire if the wire costs $0.15/ft?
2.54 cm = 1.0 in
12.0 in = 1.0 ft
Chapters 1-3 Lesson 6

6. Price of 325 cm of wire @ $0.15/ft?
Chemical Problem Solving: A Systematic Approach to Solving Chemistry Problems
Price of 325 cm of $0.15/ft?
2.54 cm = 1.0 in & in = 1.0 ft
325 cm in ft $0.15
= $1.60
2.54 cm in 1.0 ft
Chapters 1-3 Lesson 6

7. Measurement in Scientific Study: Some Important SI Units in Chemistry
PROBLEM 1.3
If you submerge a steel cube 15.0 mm on each side in 31.8 mL of water in a graduated cylinder, what is the total volume (in L) of the cylinder contents?
31.8 mL
Chapters 1-3 Lesson 6

8. Measurement in Scientific Study: Some Important SI Units in Chemistry
PROBLEM 1.4
If a raindrop weighs 65 mg on average and 5.1 x 105 raindrops fall on a lawn every minute, what mass (in kg) of rain falls in 1.5 h?
Chapters 1-3 Lesson 6

9. Measurement in Scientific Study: Some Important SI Units in Chemistry
PROBLEM 1.5
The piece of galena in Sample Problem 1.3 has a volume of 4.6 cm3. If the density of galena is 7.5 g/cm3, what is the mass (in kg) of that piece of galena?
Chapters 1-3 Lesson 6

10. Uncertainty in Measurement: Significant Figures: Determining Which Digits Are Significant
PROBLEM 1.7
For each of the following quantities, underline the zeros that are significant figures and determine the number of significant figures (sf) in each quantity. For (d) to (f), express each in exponential notation first.
(a) mg (d) mL
(b) g (e) m
(c) 850. oC (f) L
Chapters 1-3 Lesson 6

11. Problem 2.18
Fluorite, a mineral of calcium, is a compound of the metal with fluorine. Analysis shows that a 2.76-g sample of fluorite contains 1.42-g of calcium. Calculate the (a) mass of fluorine in the sample; (b) mass fractions of calcium and fluorine in fluorite; (c) mass percents of calcium and fluorine in fluorite.
Chapters 1-3 Lesson 6

12. MTS 2
Write the notation for each atomic depiction.
47 p+
62 n0
47 e-
28 e-
28 p+
33 n0
Chapters 1-3 Lesson 6

13. MTS 3 Calculating an atomic mass from isotopic composition (SP2.3)
Magnesium has three naturally occurring isotopes, 24Mg (isotopic mass amu, abundance 78.99%), 25 Mg (isotopic mass amu, abundance 10.00%), and 26Mg (isotopic mass amu, abundance 11.01%). Calculate the atomic mass of magnesium. (EOT 2.46)
Chapters 1-3 Lesson 6

14. MTS 3 Calculating an atomic mass from isotopic composition (SP2.3)
Copper has two naturally occurring isotopes, 63Cu (isotopic mass amu) and 65Cu (isotopic mass amu). If copper as an atomic mass of amu, what is the percent abundance of each isotope? (EOT 2.48)
Chapters 1-3 Lesson 6

15. Problem 4
A flask has a mass of g when empty and g when
filled with water. When the same flask is filled with
concentrated sulfuric acid, H2SO4, its mass is g.
What is the density of concentrated sulfuric acid? The density
of water at 25 oC is g/cm3.
Mass H2O = g – g = g
Volume H2O = m/D = cm3
Mass H2SO4 = g – g = g
D H2SO4 = m/V = g/cm3 = g/cm3
Chapters 1-3 Lesson 6

16. Problem 6
Hoffmannium has three common isotopes: 336Hm,
338Hm, and 340Hm. If the abundance of 340Hm
is %, what are the abundances of 336Hm
and 338Hm? The mass of 336Hm is
amu, 338Hm is amu, and 340Hm is
amu. The mass of naturally occurring
hoffmannium is amu.
60.8% = 336Hm 34.2% = 338Hm
Chapters 1-3 Lesson 6

17. Problem 3 The average density of the Earth is
5.52 g/cm3. What is the density in
lb/ft3?
345 lb/ft3
Chapters 1-3 Lesson 6

18. Chemical Problem Solving: A Systematic Approach to Solving Chemistry Problems
A furniture factory needs 31.5 ft2 of fabric to upholster one chair. Its Dutch supplier sends the fabric in bolts of exactly 200 m2. What is the maximum number of chairs that can be upholstered by 3 bolts of fabric (1 m = ft)?
3 bolts x 200 m2/1 bolt x (3.281ftx3.281ft)/1m2 x 1chair/31.5 ft2 = 205 chairs
Chapters 1-3 Lesson 6

19. Measurement in Scientific Study: Some Important SI Units in Chemistry
PROBLEM 1.6
Mercury melts at 234 K, lower than any other pure metal. What is its melting point in oC and oF?
T (K) = T (oC)
T (oC) = T (K) –
T (oF) = 9/5 T (oC) + 32
= 1.8 T (oC) + 32
Chapters 1-3 Lesson 6