CHEM115 General Chemistry I. Dr. Myton Class meets MTWR at 11:00 am. CHEM115 General Chemistry I. David M. Myton, Ph.D. (Dr. Myton) CRW327 dmyton@lssu.edu Pronto: dmyton Professor of Chemistry. Introductions. This class is not a direct competition
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David M. Myton, Ph.D. (Dr. Myton)
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Credit given for participation and accuracy
Bring to EVERY class
A
1
Yes
True
Strongly Agree
B
2
No
False
Agree
C
3


Neutral
D
4


Disagree
E
5


Strongly Disagree
Learning Objectives
"Scientific knowledge is a body of statements of varying degrees of certainty  some most unsure, some nearly sure, but none absolutely certain ... Now, we scientists are used to this, and we take it for granted that it is perfectly consistent to be unsure, that it is possible to live and not know." Richard Feynman (19181988) Nobel Prize in Physics, 1965
Brady & Senese 5th Ed
01m11vd1.mov
Macroscopic
Symbolic
2 H2(g) + O2 (g) 2 H2O(g)
Particulate (Molecular)
1.1. Chemistry is important for anyone studying the sciences
1.2. The scientific method helps us build models of nature
1.2. The scientific method helps us build models of nature
Aristotle (384 BC  322 BC)
Which statement is a hypothesis?
a: Objects on Earth are attracted by gravity.
b: When pushed off the table, my chemistry book will fall to the floor.
c: Opposite charges repel each other.
d: Mass can be converted into energy.
1.2. The scientific method helps us build models of nature
Which of the following is not a hypothesis for the observed plant growth?
1.2. The scientific method helps us build models of nature
A chicken egg is buried, left in the sun, and watered. A second egg is left above the soil, watered and left in the sun. Would this prove that soil is necessary to growth?
1.2. The scientific method helps us build models of nature
A theory isanexplanation (based on welltested, internally consistent experimental results) about why the phenomenon may occur
1.2. The scientific method helps us build models of nature
1.2. The scientific method helps us build models of nature
Which describes a tested explanation of behavior of nature?
a: a scientific law
b: a theory
c: a hypothesis
d: empirical facts
1.2. The scientific method helps us build models of nature
1.2. The scientific method helps us build models of nature
1.3. Matter is Composed of Elements, Compounds, and Mixtures
What properties change when a substance undergoes a chemical reaction?
a: physical properties
b: chemical properties
c: both chemical and physical properties
d: neither chemical nor physical properties
1.3. Matter is Composed of Elements, Compounds, and Mixtures
Which of the following is not a chemical change?
1.3. Matter is Composed of Elements, Compounds, and Mixtures
(Molecule or
Formula unit)
(Atom)
Name a thought without accepting it.
Symbol
Sodium
Copper
Cl
Nitrogen
K
Elements1.3. Matter is Composed of Elements, Compounds, and Mixtures
1.3. Matter is Composed of Elements, Compounds, and Mixtures
MOLECULAR FORMULA
C8H10N4O2  caffeine
H2O
01m06an1.mov
1.3. Matter is Composed of Elements, Compounds, and Mixtures
1.3. Matter is Composed of Elements, Compounds, and Mixtures
Classification by state is based on packing, motion, and shape
1.4. Properties of matter can be classified in different ways
1.4. Properties of matter can be classified in different ways
Which of the following is a chemical property?
1.4. Properties of matter can be classified in different ways
Intensive properties are Independent of the quantity of material present
Which is an extensive physical property?
a: mass
b: melting point
c: reactivity with water
d: temperature
1.5 Measurements are essential to describe properties
Which of the following is a quantitative observation?
1.5 Measurements are essential to describe properties
1.5 Measurements are essential to describe properties
Which types of numbers are considered “exact?” Below are the general rules.
1. Conversions between units within the English System are exact.
e.g. 12 in = 1 ft or 12 in/1 ft (In this conversion, 12 and 1 are both exact.)
2. Conversions between units within the Metric System are exact.
e.g. 1 m = 100 cm or 1 m/100 cm (In this conversion, 1 and 100 are both exact.)
3. Conversions between English and Metric system are generally NOT exact. Exceptions will be pointed out to you.
e.g. 1 in = 2.54 cm exactly (1 and 2.54 are both exact.)
e.g. 454 g = 1 lb or 454 g/1 lb (454 has 3 sig. fig., but 1 is exact.)
4. “Per” means out of exactly one.
e.g. 45 miles per hour means 45 mi = 1 hr or 45 mi/1 hr. (45 has 2 sig. fig. but 1 is exactly one.)
5. “Percent” means out of exactly one hundred.
e.g. 25.9% means 25.9 out of exactly 100 or 25.9/100 (25.9 has 3 sig. fig., but 100 is exact.)
6. Counting numbers are exact. Sometimes it is hard to decide whether a number is a “counting number” or not. In most cases it would be obvious. Ask when in doubt.
e.g. There are 5 students in the room. (5 would be an exact number because you cannot have a fraction of a student in the room.)
1.5 Measurements are essential to describe properties
USCS: oz (avdp.), lb, T
Metric: g
SI: kg
1.5 Measurements are essential to describe properties
USCS: in, ft, yd, mi
Metric: L, cm3
SI: m
1.5 Measurements are essential to describe properties
measured directly, using equipment for volumetric measure are the general rules.
calculated using dimensional (length) information and appropriate formulas. 1 cm3= 1mL
USCS: fl. oz., pt., qt., gal
Metric: L, cm3
SI: m3
Volumebulk1.5 Measurements are essential to describe properties
1.5 Measurements are essential to describe properties
Which of the following is the lowest temperature?
1.5 Measurements are essential to describe properties
Question are the general rules.
1.6. Measurements always contain some uncertainty
1.6. Measurements always contain some uncertainty
1.6. Measurements always contain some uncertainty
1.6. Measurements always contain some uncertainty
1.6. Measurements always contain some uncertainty
Question Instrument Precision
Measurements with lots of scatter are probably considered: a: not accurate and not precise. b: not accurate, but precise. c: not precise, but accurate. d: precise and accurate.
Nonzero Instrument Precision digits in a measured number are always significant
Zeros must be considered more carefully:
200.0 Instrument Precision
12100
21000
1010
200.001
0.98700
0.000012
2.200002
125
1.25e2
1.250e3
125000
0.00125
6.2303e23
6 230 300 000 000
How many significant figures?3.247 3 decimal places
41.36 2 decimal places
+125.2 1 decimal place
169.8 answer rounded to 1 decimal place
Note: Remember that some numbers are exact. Numbers that come from definitions or direct counts have no uncertainty and can be assumed to contain an infinite number of significant figures.
Question from them
Question from them
What is the proper way to report the sum 1.150 m + 3.3 m? a: 4.45 m b: 4.4 m c: 4.5 m d: 4.450 m
1.7 Units can be converted using the factorlabel method
USCS to Metric Metric to USCS
Length 1 in. = 2.54 cm 1 m = 39.37 in
1 yd = 0.9144 m 1 km = 0.6215 mi
1 mi = 1.609 km
Mass 1 lb = 453.6 g1 kg = 2.205 lb
1 oz = 28.35 g
Volume 1 gal = 3.785 L 1 L = 1.0567 qt
1 qt = 946.4 mL
1 oz (fluid) = 29.6 mL
It is also useful to know that 1 mL = 1 cm3=1 cc
1.7 Units can be converted using the factorlabel method
1. Write the number to be converted as a fraction (with units)
2. Identify the target units
3. Are the starting units in the same system as the target?
1.7 Units can be converted using the factorlabel method
4. Use the form of the conversion factor that allows the units to cancelthey must be on opposite levels of the fraction to cancel.
5. Continue adding conversion factors until the units match the target units.
2nd Check are all units written on the page two times? If so, you have enough info to start the problem.
1.7 Units can be converted using the factorlabel method
Question from them
What conversion factors would be necessary to convert miles per gallon to km per liter? a: (1.6 km / 1 mi) and (1 gal / 3.79 L) b: (1 mi / 1.6 km) and (1 gal / 3.79 L) c: (1.6 km / 1 mi) and (3.79 L / 1 gal) d: (1 mi / 1.6 km) and (3.79 L / 1 gal)
Question from them
What is the volume of a box that measures 50 cm by 1.0 m by 2000 mm?a: 100,000 m3 b: 10,000 m3 c: 100 m3 d: 1.0 m3
e: 1 m3
Chalcopyrite, the principle ore of copper (Cu) contains 34.63 percent Cu by mass. How many grams of Cu can be obtained from 5.11e3 kg of the ore?
If a bracelet is made of silver and copper with a mass of 38.9 g contains 32.3 g of silver, what is the percentage of silver and of copper. How many grams of copper are in a 50 gram bracelet?
Density(g/cm 38.9 g contains 32.3 g of silver, what is the percentage of silver and of copper. How many grams of copper are in a 50 gram bracelet?3)
Water 1.00
Aluminum 2.70
Iron 7.86
Gold 19.3
Air 0.0012
Density(d)is an intensive property defined as the ratio of an objects mass (m) to volume (v), d = m/v
A student pipets 25.0 0mL of isopropyl alcohol into an empty flask weighing 35.182 g. She finds the mass of the flask + alcohol is 54.707 g. Calculate the density of the alcohol.
The density of a solution of sulfuric acid is 1.285 g/cm flask weighing 35.182 g. She finds the mass of the flask + alcohol is 54.707 g. Calculate the density of the alcohol.3, and it is 38.08% acid by mass. What volume of the acid solution in mL do you need to supply 125 g of sulfuric acid?
A solution of sugar in water has a density of 1.05 g/cm flask weighing 35.182 g. She finds the mass of the flask + alcohol is 54.707 g. Calculate the density of the alcohol.3. If you have 250. mL of the solution and if the solution is 8.1% by weight sugar, how many grams of sugar are in the solution.
Question flask weighing 35.182 g. She finds the mass of the flask + alcohol is 54.707 g. Calculate the density of the alcohol.
Air at room temperature has a density of about 0.0012 g/cm3. What is the mass of 1.0 L of air? a: 1.2 g b: 12 g c: 0.0012 g d: none of these
A crash sounds from the lab a large vial of mercury has fallen from a broken shelf. We call the hazardous materials team to report the spill, about 2.0 quarts of mercury. They ask for the mass what is it? (hint: d=13.69g/mL & 1 L = 1.0567 qt)
1.8. Density is a useful intensive property
Amethyst is a colored form of the mineral quartz in which the purple color comes from traces of the element manganese. To determine the density of amethyst, you take a stone having a mass of 15.25 g and place it in a 100. mL graduated cylinder containing 45.0 mL of water. On adding the stone the water surface rises to the 50.8 mL mark. What is the density of amethyst?