CHEMISTRY 110 LECTURE



Chamras

CHEMISTRY 110 LECTURE NOTES

EXAM 2 Materials: Chp’s. 5 (in part), 6, 7, 8

The Universe:

The Sciences:

Definition for Energy:

Types of Energy:

Definition for Matter:

Types of Matter: Later…

Scientific Method: (Scientific laws, theories, hypotheses, experiments, measurements, etc.…)

Math Tools for Chemistry

a. Scientific Notation

Scientific notation is used for expressing very large or very small numbers

Decimal Notation Scientific Notation

153,000,000,000,000 m ---------- 1.53 x 1014 m

0.0000000005 g ---------- 5 x 10–10 g

What is the use of scientific notation?

Template for Scientific Notation: # x 10exp. Condition on #: 1 < # < 10

Example 1:

Decimal Notation Scientific Notation

453442

0.00034200024

*Common Numeric Notations:

Decimal:

Exponential:

Scientific:

b. Measurements:

Importance:

Properties:

a) Units:

b) Accuracy:

c) Significant Figures (Sig. fig.) in Measurements:

To read, record all of the certain digits and one uncertain digit.

Example 1: Measuring temperature:

oT = 25oC or oT = 25.45 oC

40oC 27oC

30oC 26oC

20oC 25oC

Example 2: Measuring mass:

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The number of Sig. Fig.’s: In measured numbers will show the degree of uncertainty/certainty of the measuring device.

d) Determining the Number of Significant Figures In A Measured Value:

|# |Digit Type |Example |Significant? Y/N |Total # of Sig. Fig’s. |

|1 |Non-zero Digits | | | |

|2 |Leading Zeros | | | |

|3 |Captive Zeros | | | |

|4 |Trailing Zeros | | | |

| | | | | |

Example: How many significant figures do the following numbers contain?

5.07 m2

0.0000876 m.s–1

998.9877000 km

0.0000009830000 mL

e) Rounding-Off Numbers:

1. If the first digit to be dropped is < 5 ( eliminate the number [Round-down]

2. If the first digit to be dropped is ≥ 5 ( [Round-up]

Example: Round the following numbers to contain 3 significant figures.

12.4567 m2 : 1324.099 km :

2.5389 x 1012 g: 0.00497923 mg:

f) Significant Figures In Calculations:

1. Multiplication-Division Rule: Answer contains the same number of significant figures as the measurement with the fewest number of significant figures.

Example:

2. Addition-Subtraction Rule: Answer contains the same number of decimal digits as the measurement with the fewest number of decimal digits.

Example:

* What if we have combined calculations? …& How about the units?

Example 1: (4.04 + 143) x (3.550 + 5.4090) =

Example 2: (9.10 x 104cm) x (181.88 x 10–3cm2) =

(22.13 s – 19.8 s) x (32cm + 64.22cm)

* Exact numbers:

Example:

g) Measurement Systems:

1. The International System (SI): The SI is the scientific system of units of measurement

METRIC BASE UNITS

LENGTH MASS VOLUME TIME

Base Unit: meter gram liter second

Symbol: m g L s

SI Prefixes:

*Why are SI prefixes needed?

0.00000000050m = ? nm

***Must Learn ASAP***

Prefix Symbol Exponential form Decimal form Meaning

Terra T 1012 1,000,000,000,000 Trillion

Giga G 109 1,000,000,000 Billion

Mega- M 106 1,000,000 Million

Kilo- k 103 1,000 Thousand

Deca- da 101 10 Ten

Deci- d 10–1 0.1 Tenth

centi- c 10–2 0.01 Hundredth

milli- m 10–3 0.001 Thousandth

micro- µ 10–6 0.000001 Millionth

nano- n 10–9 0.000000001 Billionth

pico- p 10–12 0.000000000001 Trillionth

2. The English System:

*Pros and Cons for SI and English Systems of Measurements:

1. Intuitive?

2. Systematic? / Scientific?

h) Dimensional Analysis Method: A system used for converting from one unit into another.

Type 1:

Example 1: Convert 67 centimeters into meters

Example 2: How many milligrams are there in 1.20 x 104grams?

Type 2:

Example 1: Convert 1.67 centiliters into kiloliters.

Example 2: How many nanoseconds are there in 12.02 x 102 centiseconds?

Type 3:

Example 1: Convert 25.4 into .

Example 2: How many centiliters per gram are there in 100.2 x 10-2 megaliters per decagram?

Type 4:

Example 1: Convert 1.67 cm2 into km2.

Example 2: How many cubic deciseconds are there in 132.6 x 104 cubic milliseconds?

Type 5:

Example 1: Convert 25.4 into .

Example 2: How many cubic meters per nanoseconds squared are there in 15 x 10–4 cubic kilometers per picoseconds squared?

i) Conversion Factors & Significant Figures:

1. SI into SI

English into English

2. SI into English

English into SI

More Sample Conversion Problems:

1. How many millimeters are there in 3.4 meters?

2. How many liters are there in 55 µL?

3. How many kilometers are there in 3.46 x 1013 mm?

4. How many milliliters are in 1.2 x 106 deciliters?

5. How many milligrams in 32 lbs?

6. How many km is a 100.0 yd football field?

7. What is 2.00 drams in gallons? (1 dram = 3.6967 x 10-3µL)

8. If gas is 66 cents per L, what is this in dollars per gallon?

9. If a faucet is dripping at 1.0 drop per sec, how many mL per week is this? (16 drops = 1.0 mL)

10. A piece of wood is 15 cm x 24 cm x 11 cm.

a) What is the volume of this wood?

b) What is the volume in cubic meters?

11. If a glass holds 4.600 x 10 4 mm3 of water, what will this volume be in cubic inches?

12. The estimated amount of recoverable oil from the field at Prudhoe Bay in Alaska is 9.6 x 109 barrels. What is the amount of oil in cubic meters? [12 barrel = 42 gal (exact)] [1 qt = 9.46 x 10-4 m3]

Volume:

Definition:

Two Volume Systems in SI:

Cubed-Based Volume Liter-Based Volume

Chemistry

a) Mass:

b) Weight:

c) Density:

1. Definition:

2. Equation:

3. Unit:

Density Problems:

Type 1.

Example: If 40.53 grams of gold has a volume of 2.10 cm3, what is its density?

Type 2.

Example: Calculate the mass of 251 mL of Al. (Density of Al = 2.7 g/cm3)

Type 3.

Example: What is the volume of 2.5 kg of gold?

d) Temperature:

Definition:

Units:

Conversions: 2 points to address when devising a conversion factor:

1. Starting point difference:

2. Gradient difference:

------------------ --------------- --------------

----------------- ---------------- -------------

Fahrenheit Celsius Kelvin

Scale Scale Scale

1. Degrees Celsius (( Degrees Fahrenheit

2. Degrees Celsius (( Kelvin

The Periodic Table of the Elements

Essential Vocabulary:

1. Periods:

2. Groups or families:

3. Metals:

4. Non-metals:

5. Metalloids or semi-metals:

6. Transition metals:

7. Diatomic elements:

8. Common Group Names:

Matter:

Definition:

States of Matter:

SOLID LIQUID GAS PLASMA

Cartoon:

Energy:

Density:

Shape:

Ability to flow:

State Changes:

Properties & Changes:

Physical Chemical

Properties

Examples

Changes

Examples

Classify the following changes as physical or chemical.

1. Changing a sample of matter from one physical state to another 6. Gasoline evaporates

2. Changing the size or shape of the substance 7. The statue of liberty turns green

3. Mixing or dissolving two or more substances 8. Tearing paper

4. Undergoing a chemical reaction 9. A tree stump rots

5. Paper burns to produce CO2 and H2O 10. Dissolving a package of jello in water

Types of Particles:

A. Atoms: The smallest units/particles that can exist that will still have the characteristics of the element.

Illustration:

Example:

B. Molecules: The smallest unit of two or more atoms bonded together.

Illustration:

Example:

C. Ions: Positively or negatively charged atom or group of atoms.

Illustration: After covering “Subatomic Particles” section.

Example:

Types of Matter

Chart:

Electrostatic Law of Attraction

Opposite charges attract each other

Same charges repel each other

Subatomic Particles

Modern Atomic Theory: A theory on structure of atoms.

| |Particles |Relative Mass |Charge |

|Electronic Cloud | | | |

|Nucleus | | | |

| | | | |

…Back to the Periodic Table of Elements:

Arrangements logic:

Atomic Number (Z):

The ID # for Elements

Atomic Mass (A):

Unit: amu

1 amu = 1.66053886 x 10–24g

45 Common Elements

|Symbol |Name | |Symbol |Name |

|Ag |silver | |K |potassium |

|Al |aluminum | |Kr |krypton |

|Ar |argon | |Li |lithium |

|Au |gold | |Mg |magnesium |

|B |boron | |Mn |manganese |

|Ba |barium | |N |nitrogen |

|Be |beryllium | |Na |sodium |

|Br |bromine | |Ne |neon |

|C |carbon | |Ni |nickel |

|Ca |calcium | |O |oxygen |

|Cd |cadmium | |P |phosphorus |

|Cl |chlorine | |Pb |lead |

|Co |cobalt | |Ra |radium |

|Cr |chromium | |Rb |rubidium |

|Cs |cesium | |Rn |radon |

|Cu |copper | |S |sulfur |

|F |fluorine | |Sb |antimony |

|Fe |iron | |Si |silicon |

|Fr |francium | |Sn |tin |

|H |hydrogen | |Sr |strontium |

|He |helium | |Xe |xenon |

|Hg |mercury | |Zn |zinc |

|I |iodine | | | |

This is the basic alphabet of Chemistry you need to know.

Isotopes

Definitions:

1.

2.

Examples of Isotopes:

Isotopes of carbon:

|Isotope |Protons (+) |Electrons (-) |Neutrons (0) |Atomic Number (Z) |Atomic |

| | | | | |Mass (A) |

| | | | | | |

| | | | | | |

| | | | | | |

Isotopes of Hydrogen:

|Isotope |Protons (+) |Electrons (-) |Neutrons (0) |Atomic Number (Z) |Atomic |

| | | | | |Mass (A) |

| | | | | | |

| | | | | | |

| | | | | | |

Sample Problems:

1. What is the elemental isotope with 8 protons, 8 electrons, and 10 neutrons?

2. What is the elemental isotope with 19 electrons, 24 neutrons and 19 protons?

Ions

Definition:

How do atoms turn into ions?

Types of ions:

1.

Example:

2.

Example:

Common Trends in Ionization

Isotope Problems with Ions:

1. What elemental isotope has 2 more neutrons, and 2 less protons than O-18?

2. What elemental isotope has 4 fewer neutrons, 1 fewer electron, and 2 fewer protons than Br-81?

Ionic Compounds

Remember: Compounds are neutral (they have a net charge of zero).

Formulas for Ionic Compounds:

*Principle of neutrality:

|Atom 1 |Atom 2 |Cation formula |Anion formula |Compound formula |

|lithium |sulfur | | | |

|calcium |fluorine | | | |

|aluminum |nitrogen | | | |

|chlorine |phosphorus | | | |

|sodium |oxygen | | | |

|rubidium |bromine | | | |

|magnesium |nitrogen | | | |

Exercises:

1. Write the formula for the ionic compound made with ions of:

a) Potassium and oxygen:

b) Calcium and bromine:

2. Complete the table below:

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