Period A 2010 Editor:James Payne

1.1 Chemistry

What Is Chemistry? page 7(Shannon Lamy)

• Chemistry is the study of the composition of matter and the changes that matter undergoes.
• Because living and nonliving things are made of matter, chemistry affects all aspects of life and most natural events.

What is Matter?

• Matter is anything that has mass or occupies space. Matter can be INVISIBLE.

Areas of Studypage 8(Shannon Lamy)

• There are 5 basic areas of study in Chemistry.
  1. ORGANIC CHEMISTRY is the study of all chemicals containing carbon. Carbon is contained in most chemicals found in living organisms.

  The chemicals in inhalers are created by organic chemists.

  
  2. INORGANIC CHEMISTRY is the study of chemicals that do not contain carbon. This often includes nonliving things.

*Ex. rock.

3.
BIOCHEMISTRY
is the study of processes that take place in organisms.
*Ex. muscle contraction and digestion

4.
ANALYTICAL CHEMISTRY
focuses on the composition of matter.
*Ex. measuring the level of lead in drinking water.

5.
PHYSICAL CHEMISTRY
deals with mechanism, the rate, and the energy transfer that occurs when matter undergoes a change.

Though these are all individual areas of chemistry, they ofter do overlap in study.

Pure and Applied Chemistry

page 9 (Brandon Boisclair)

• Pure Chemistry is the pursuit of chemical knowledge for its own sake.

- Chemists do these experiments/research on fundamental aspects of chemistry (just for your own personal use)

• Applied Chemistry is research that is designed to answer a specific question

- Most chemists do research that is designed to answer a specific question.

Pure and Applied Chemistry can lead directly to an application, but an application can exist before research is done to explain how it works.

TECHNOLOGY

• Technology is the means by which a society provides its members with those things needed and desired.
• It allows humans to do some things more quickly or with less effort.
• It allows people to do things that would be impossible to humans.

Why Study Chemistry?

page 10 (Brandon Boisclair)

• Chemistry can be useful in explaining the natural world, preparing people for career opportunities, and producing informed citizens.

Explaining the Natural World

• Chemistry can help us satisfy our natural desire to understand how things work.

- EX. It can explain why apples turn brown upon exposure to air.

SECTION 1.1 ASSESSMENT
1. Explain why chemistry affects all aspects of life and most natural events.

2. Name the five traditional areas into which chemistry can be divided. _

3. Describe the relationship between pure chemistry and applied chemistry.

4. List 3 reasons for studying chemistry. _

1.2: Chemistry Far and Wide

• Materials (page 12 Andrea Luongo)

  • Chemists design materials to fit specific needs
  • There are two different ways to view things in the world: 
    1. MACROSCOPIC- large enough to see with your eye Ex. A dog.
    2. MICROSCOPIC- so small that you need to use a type of magnifier to see it Ex. Bacteria.

• Tools and materials in society are designed to make our daily activities quicker and easier

• Energy (page 13 Andrea Luongo)

  • Energy is the capacity for doing work or producing heat
  • It is necessary for all of society and is used in technology, transportation, and industrialization
  • Chemists help regulate the production, conservation, and storing of energy

• Production of Energy
• Fossil fuels are formed from the remains of plants and animals to produce energy
  • Scientists are limited to fossil fuels so they are looking for other ways to produce these sources of energy

• Conservation of Energy
  • Insulation is the easiest way to store energy
  • Insulation acts as a barrier for heat flow from houses and the environment
  • One type of insulation is called SEAgel, which is a lightweight foam made from seaweed

The pink in this picture is the insulation.

• Storing Energy
  • Batteries use chemicals to store energy that are released as an electrant current when they are used.
  • Batteries vary in size, shape, and the amount of energy that they can hold
  • Batteries were first developed for NASA

•  Medicine and Biotechnology (page 14 Andrea Luongo)

  • Chemistry is the main supplier of medicine, materials, and technology that doctors use to treat patients
  • Biochemists work with medicine, study the structure of matter found in the human body, and they study chemical changes that occur in cells

• Medicine
  • Over 2,000 prescription drugs have been designed to treat infections, blood pressure levels, and emotions like depression
  • Sucessful drugs interact with the chemicals in cells (these drugs are a structure-fits-function design from the drug to the cells)

• Materials
  • Chemistry can supply the proper materials to repair or replace body parts
    • Ex. A damaged artery can be replaced with a plastic tude and artificial hips and knees can replace hips and knees with worn-out joints
  • Certain chemicals can keep our bodies working by replacing the non-working areas in our bodies

• Biotechnology
  • Genes in DNA store information that controls the changes that occurs in cells
    • There are over 30,000 human genes
  • Biotechnology applies science to the production of biological products or processes
  • Altering DNA depends on the transfer of genes from one organism to another
  • In the future, gene therapy can treat some diseases (non-working genes may be replaced with working genes)

DNA:

• Agriculture (page 15 Andrea Luongo)

  • Chemists help developed more productive crops and safer, more effective ways for crop protection
  • Productivity measures the amount of edible food that is grown on a unit of land
    • Factors that decrease productivity:
      1. Poor soil quality
      2. Lack of water
      3. Weeds
      4. Plant Diseases
      5. Pests
  • Chemists test soil for the correct chemicals for plant growth
  • Chemists use biotechnology to create plants more likely to survive droughts and insects attack
  • To conserve water, ceratin jellyfish genes are used to cause plants to glow when they need water (These plants are removed before harvest)

• Crop Protection
  • Chemists created chemicals that can help prevent pests from killing plants
  • They even use insect chemicals to fight insect pests so that fewer pests are produced

• The Environment (page 16 Haley Conatser)

-A pollutant is a material found in air, water, or soil that is harmful to humans or other organisms
- Chemists help to identify pollutants and prevent pollution
- An example of a pollutant is Lead


Identify Pollutants
- Lead was the most common pollutant throughout our history and still is very common today
- Too much lead can could brain damage but not enough lead can also cause permanent damage to the nervous system

Prevent Pollution
- Use of lead paint in houses was banned in 1978 and using lead in gasoline and in public water supply systems was banned in 1986
- 39 million homes built before 1978 still contain lead paint and still harms children today
- The strategies used to prevent lead poisoning include testing children's blood, regulation of home sales to families with young children and public awareness
campaigns with posters

• The Universe (page 17 Haley Conatser)

- To study the universe, chemists gather data from afar and analyze amtter that is brough back to Earth
- In the early 1800's scientists began to study the composition of stars by analyzing the light they transmitted to Earth
- In 1895, William Ramsay discovered helium on Earth
- Scientists depend on matter brough back to Earth by astronauts or on probs that can analyze matter in space
- Based on the data the robot ( pictured below ) collected, a large amount of water once existed on the surface of Mars

• Nature's Pharmacy

- About 40 precent of all modern medicines come from chemicals produced by plants or animals
- Chemists must first identiy the effective, or active ingredient.
- Then they must purify the chemical and show that it is safe for human use
- Chemists often modify a chemical to make it more effective or less toxic
Examples:
1. Foxglove - It causes heart muscle cells to contract with more power, which increatses the ability of the hear to pump blood

2. Willow Bark - People used to make a tea out of willow bark which helped treat headaches and other ailments. It is now used in aspirin


3. Cone Snail- This toxins are being studied as possible treatments for chronic pain and nervous system disorders


- Chemicals from natural sources are not always effective or harmless
- the herb Ephedra, contains the chemical ephedrine, whcih is associated with increased blood pressure, abnormal heart rates, a higher risk of stroke, and even death

Thinking Like a Scientist (20-27)

Christian Cooke (co-editor) and Nate Lynch

1928- Alexander Fleming discovered Penicillin which can kill a wide range of harmful bacteria.

Alchemy

-chemistry comes from alchemy
-Alchemists studied matter
-practiced in China and India in about 400 BC
-8th century Arabs brought alchemy to Spain
-it then spread to most of Europe
Practical Alchemy- works w/ metal, glass, and dyes
Mystical Alchemy- concepts of Perfection

Alchemist developed the tools and techniques fro working with chemicals

An Experimental Approach to Science

Lavosier help to transform chemistry from science of observation to science of movement

Scientific Method- a logical systematic approach to the solution of a scientific problem

-Steps-

1. observe
2. hypothesis
3.experiment
4. analyze
5. conclusion

Developing Theories
· Hypothesis becomes a theory after it meets the test of repeated experimentation and is raised to a higher level of ideas
· Theory is a well tested explanation for a broad set of observations
· When scientists say theories can’t be proven, they aren’t saying it’s unreliable

Scientific Laws is a concise statement that summarizes results of many observations/experiments
-doesn’t try to explain relationship it describes
-explanation requires a theory
Collaboration and Communication
-when scientists collaborate and communicate they increase the likelihood of a successful outcome
Collaboration
-choose to collaborate for different reasons
-each scientist typically brings different knowledge, different approach on a problem
-There may be practical reason: sharing of knowledge/ ideas
-Collaboration not always a smooth process
-conflicts over resources, amount of work, publishing, credit
Communication
-the way scientists communicate with each other and the public has changed over the years
Used to:
-exchange ideas thru letters
-also made societies to discuss their work
-Published journals to keep up with new discoveries
Today:
-work as a team
-communicate face to face
-also exchange ideas via e-mail, phone and international conferences
-still use scientific journals today… articles are first reviewed before publishing
-Internet
-major source, not always reliable
CHECK SOURCE

the scientific method song


1.4

Problem solving in Chemistry (PJ Hamill)
Pages 28-32
Key concepts:
· The general approach to solve a problem
· The three steps for solving a numeric problem
· 2 steps for solving conceptual problem
Skills used in solving problems:
· Trial and error
· Developing a plan and following through
Solving a Numeric Problems
· Analyze
o Identify what is known
o Identify the unknown
o The known may be a measurement or an equation that shows a relationship between measurements
o If you are expecting the answer ( the unknown) you should determine what units the answer should be in.
o Using tables or graphs may help
· Calculate
o Converting if needed
o Using formulas
· Evaluate
o After you calculate an answer you evaluate it
o While evaluating answer these questions
§ Is the answer reasonable?
§ Does it make sense?
§ Did you copy the information correctly?
§ Did you choose the correct equation?
o Check your calculations
o Make sure your answer is in the right unit
Solving Conceptual Problems
· Analyze
· Solve
Chapter 3.1: Measurements and Their Uncertainty
(Dakota Pimentel pg 63-72)
3.1 Measurements and Their Uncertainty
Using and Expressing Measurements
Measurement: A quantity that has both a number and unit, (ex. 111lbs. 65 mph 32
°
F …)

• Key concept: Measurements are fundamental to the experimental sciences. It is important to be able to make accurate measurements, and decide weather a measurement is correct
• SI most commonly used units in science (international system of measurements)
• Scientific notation is often used in science to express extremely large, or small measurements, and numbers in a simplified manner.

· Written as a number greater than or equal to one and les than ten (with two decimal places, hundredths place) multiplied by a coefficient, ten to the power of x. x being the number to make the statement a true approximation
Ex. 602,000,000,000 is written 6.02x1011

Accuracy, Precision, and Error
Accuracy: a measure of how close a measurement comes to the actual value of what is being measured.
Precision: How close a set of measurements are to one another (how they vary in result)
(see pg 64, figure 3.2 for illustrated representation of accuracy and precision)

• The “closeness” of the darts represents the degree of precision
• The distance from the bull’s eye represents the degree of accuracy in this example

Determining error
· There is a difference between the accepted value (widely accepted value) and the experimental value (the actual measured value one might record)
· Ex. Accepted value for the boiling point of purified water: 100c
But your thermometer may read 98.1c, this is the experimental value
· Error is the experimental value minus the accepted value
· The degree of error can be either positive or negative.
· The percent error is calculated by dividing the absolute value of the error by the accepted value, then multiplying that quotient by 100% (see diagram in book pg. 65 for accurate representation of equation.
· Not every measuring tool is accurate, and can be the factor causing the difference between the experimental and accepted value
Significant Figures in Measurements
· On non digital measuring tools it is possible to guess a more accurate number based on the reading as it relates to the calibration marks, for instance if something measured in between the 2.1lbs hash and the 2.2lbs mark it would be fair to estimate that that object weighed about 2.15lbs if it appeared to be directly centered.
· :: all of the known digits, plus the next estimated digit
Significant figures in calculations

• Calculated measurements must be expressed with the same nimber of digits as previously stated…
• Ex. 7.7x5.4=41.58 but must be expressed with two digits as 42

(Page 63: Zoey Killion)

Using and Expressing Measurements:

• Measurement: a quantity that has both a nymber and a unit
• Measurements are fundamental to the expirimental sceinces. For that reason, it is important to be able to make measurements and to decide whether a measurement is correct.
• Scientific Notation: a given number is written as the product of two numbers - a coefficient and 10 raised to a power
  • Example: the number 602,000,000,000,000,000,000,000 written in scientifc notation is 6.02 X 10 to the 23rd power

Accuracy, Precision, and Error

(Pages 64-65: Zoey Killion)

• Accuracy: a measure of how close a measurement comes to the actual or true value of whatever is measured
• Precision: a measure of how close a series of measurements are to one another
• To evaluate the accuracy of a measurement, the measured value must be compared to the correct value. To evaluate the precision of a measurement, you must compare the values of two or more repteated measurements.
• Accepted Value: the correct value based on reliable references
• Experimental Value: the value measured in the lab
• Error: the difference between the accepted value and the experimental value
  • ERROR = experimental value - accepted value
• Percent Error: the absolute value of the error divided by the accepted value, multiplied by 100%
  • PERCENT ERROR = ( absolute value of ) lerrorl / (divided by) accepted value X (multiplied by) 100%
    • Example: Suppose you use a thermometer to measure the boiling point of pure water at standart pressure. The thermometer reads 99.1 degrees Celcius. You probably know that the true or accepted value of the boiling point of pure water under these conditions is actually 100.0 degrees Celcius. There is a difference between the accepted value and the expirimental value. For the boiling-point measurement, the error is 99.1 - 100.0, or -.9 degrees Celcius. For the boiling-point measurement, the percent error is calcuated as follows:

Percent Error = (the absolute value) of 99.1 degrees Celcius - 100.0 degrees Celcius / (divided by) 100.0 degrees Celcius X (multiplied by) 100%
= .9 / 100.0 X 100%
= 0.009 X 100%
= .9%

In the diagram, it shows the difference between accuracy and prescision using a dartboard and darts on the board.

In the diagram, it shows the difference between accuracy and prescision using a dartboard and darts on the board.

Significant Figures in Measurements

• Significant Figures: in a measurement, includes all of the digits that are known, plus a last digit that is estimated
• Measurements must always be reported to the correct number of significant figures because calculated answers often depend on the number of significant figures in the values used in the calculation.

Rules for Determining whether a Digit in a Measured Value is Significant:

(Pages 66-67: Zoey Killion)

1. Every nonzero digit in a reported measurement is assumed to be significant.
2. Zeros appearing between nonzero digits are significant.
3. Leftmost zeros appearing in front of nonzero digits are not significant. They act as placeholders.
4. Zeros at the end of a number and to the right of a decimal point are always significant.
5. Zeros at the rightmost end of a measurement that lie to the left of an understood decimal point are not significant if they serve as placeholders to shwo the magnitude of the number.
6. There are two situations in which numbers have na unlimited number of significant figures. The first involves counting.

For more practice with the information in Chapter 3.1 - Measurements and Their Uncertaintiy, go to this website for a self-assesment:

http://www.phschool.com/webcodes10/index.cfm?fuseaction=home.gotoWebCode&wcprefix=cda&wcsuffix=1030

3.2 The International System of Units (page 73)

Measuring with SI Units (page 73, Alex Nunan)

• International System of Units- "SI", revised version of the metric system. Five basic SI units:
  • meter: "m", length
  • kilogram: "kg", mass
  • kelvin: "K", temperature
  • second: "s", time
  • mole: "mol", amount of substance

Units and Quantities (page 74, Alex Nunan)

*Different quantities require different units- know units corresponding to what you are measuring before you make a measurement

• Units of Length-
  • SI basic unit of length is the meter. All length measurements can be expressed in meters.
  • Some things might be more convenient to use a unit of length that has a prefix:
    • mega (m)- 1 million times larger than unit it precedes
    • kilo (k)- 1,000 times larger than unit it precedes
    • deci (d)- 10 times smaller than unit it precedes
    • centi (c)- 100 times smaller than unit it precedes
    • milli (m)- 1,000 times smaller than unit it precedes
    • micro (
    • nano (n)- 1,000 million times smaller than unit it precedes
    • pico (p)- 1 trillion times smaller than unit it precedes
  • The most common units are the centimeter, meter, and kilometer
• Units of Volume-
  • volume- space occupied by any sample of matter
    • calculate volume of a cube or solid rectangle by multiplying its length by its width by its height
    • most common metric units of volume: liter, milliliter, cubic centimeter and microliter
  • devices for measuring liquid volume include:
    • graduated cylinders
    • pipets
    • burets
    • volumetric flasks
    • syringes
  • volume of solids, liquids and gases change with temperature
    • therefore, accurate devices are used at a given temperature, usually around 20 degrees Celsius (room temp.)

Units of Mass (page 76, Becky Hyatt)

• the mass of an object is measured in comparison to a standard mass of 1 kilogram (kg), which is the basic SI unit of mass
• a gram (g) is 1/1000 of a kilogram
• common metric units of mass include the kilogram, gram, milligram, and microgram
• you can use a platform balance to measure the mass of an object
• an analytical balance is used to measure objects of less than 100 g
• weight is a force that measures the pull on a given mass by gravity
• weight, a measure of force, is different from mass, which is a measure of the quantity of matter

Units of Temperature (page 77, Becky Hyatt)

• temperature is a measure of how hot or cold an object it
• when two objects at different temperatures are in contact, heat moves from the object at the higher temperature to the object at the lower temperature
• almost all substances expand with an increase in temperature and contract as the temperature decreases (exception of water)
• example- thermometers are used to measure temperature
• scientists commonly use two equivalent units of temperature, the degree Celsius and the kelvin
• the Celsius scale sets the freezing point of water at 0 degrees and the boiling point of water at 100 degrees Celsius
• on the Kelvin scale, the freezing point of water is 273.15 kelvins (K), and the boiling point is 373.15 K
• the zero point on the Kelvin scale, 0 K, or absolute zero, is equal to -273.15 degrees Celsius
• you add or subtract 273 to convert from one temperature to another
• K = degree Celsius + 273, degree Celsius = K - 273

Sample Problem 3.4 (page 78, Becky Hyatt)

• converting between temperature scales:
1. Analyze- list the known and the unknown
2. Calculate- solve for the unknown
3. Evaluate- Does the result make sense?

Units of Energy (page 79, Becky Hyatt)

• energy is the capacity to do work or to produce heat
• the joule and the calorie are common units of energy
• the joule (J) is the SI unit of energy
• one calorie (cal) is the quantity of heat that raises the temperature of 1 g of pure water by 1 degree Celsius
• 1 J = 0.2390 cal, 1 cal = 4.184 J

3.3 Conversion Problems (Pages 80-87)

Conversion Factors (Elizabeth Howard Pages 80-81)

• Conversion Factor: A ratio of equivalent measurements used to convert a quantity from one unit to another.

• The measurement in the numerator (on the top) is equal to the measurement in the denominator (on the bottom)

• When a measurement is multiplied by a conversion factor, the numerical value is generally changed, but the actual size of the quantity measured stays the same

• Conversion factors are useful in solving problems in which a given measurement must be expressed in some other unit of measure

Smaller Number à1mßLarger Unit
Larger Number à100 cm ßSmaller Unit


3.4 Density (Pages 89 - 93)Group Members: Caroline Rubino, Olivia Richardson, Mike Hanley
Determining Density (Pages 89-90, Mike Hanley)

• Density can be determined by using the mass and volume of an object
• Density is the ratio of the mass of an object to its volume
• The formula for density is shown below

.

• Density is an intensive property that depends only on the composition of a substance, not on the size of the sample
• With a mixture, density can vary because the composition of a mixture can vary
• If two liquids of different densities were put into the same glass, the one with the lower density would float to the top.

• If two different gasses of different densities are in the same space, the gas with the lower density would rise above the other
• Helium is less dense than air, therefore a helium balloon is able to float and rise in the air

Density and Temperature (Pages 91-92, Olivia Richardson)

• Density is the ratio of an object's mass to its volume, if volume changes with temperature, then the density must also change with it.
• The density of substances generally decreases as its temperature increases

Sample Problem for Calculating Density: A copper penny has a mass of 3.1 g and a volume of 0.35 cm. What is the density of copper?

1. Analyze: Knowns- mass=3.1 g and volume=.35 cm Unknown- Density=? g/cm Remember density=mass/volume
2. Calculate: Solve for the Unknown Density=mass/volume = 3.1g/.35 cm = 8.8571 which rounds to 8.9 g/cm
3. Evaluate: knowing that a piece of copper has a volme of .3 cm and mass of about 3 grams, we know that if a piece of copper has three times the amount of volume, it should also have three times the amount of mass which would be 9 grams. This agrees with the results gotten.

Here is a practice problem to try on your own: A bar of silver has a mass of 68 grams and a volume 6.48 cm. What is the density of silver? You can also use Density to calculate volume. Here is another problem you can try: What is the volume of a pure silver coin that has a mass of 14 g? The density of silver is 10.5 g/cm.

Analytical Chemistry (Caroline Rubino)

• Analytical chemists focus on making quantitative measurements
• Quantitative measurement- usines measurements to measure different objects and materials. It involves a numerical measurement.
• As an analytical chemist you would spend time makiing measurments and caculations to solve laboratory and math based research problems.
• As an analytical chemist you must be able to think creatively and devolpe new ways for finding solutions.