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Biology I Chemistry

Building blocks of matter

• Atom - the smallest unit of an element that maintains the chemical identity of that element

• Element - a substance that cannot be separated into simpler substances.

• Compound - contains two or more elements in a fixed proportion.

Changes in Matter

• Physical change - changes the appearance but not the identity of the substance.

• Chemical change - changes the identity of the substance

• Law of Conservation of Matter:

• Matter is neither created nor destroyed in any process.

Classification of Matter • Matter can be either a pure substance (element

or compound) or a mixture.

• Mixture - a blend of two or more pure substances

• Heterogeneous mixture - a mixture that has visibly different parts. Ex: Chocolate Chip Cookie

• Homogeneous mixture - a mixture that does not have visibly different parts. Ex: Sugar Cookie

H H H

O

H H

O

Na

Cl

2

Notebook #1 1.  What is an atom? 

2.  What is the relationship between an element and a compound? 

3.   What is the difference between a physical change and a chemical change? 

4.  What is the law of conservation of matter? 

5.  What is the difference between a pure substance and a mixture? 

6.  What is the difference between a heterogeneous mixture and a homogeneous mixture? 

The Periodic Table •  The elements are organized into groups based on similar

chemical properties. This organization is known as the periodic table.

•  Group - vertical column

•  Period - horizontal rows

•  Metal - good conductor of electricity and heat.

•  Nonmetal - poor conductor of heat and electricity.

•  Metalloid - some characteristics of metals and some of nonmetals.

•  Noble Gases - last group of the periodic table, highly stable and unreactive.

The Scientific Method •  The scientific method is a logical approach to solving

problems by observing and collecting data, formulating hypotheses, testing hypotheses, and formulating theories that are supported by data.

•  Qualitative - descriptive data

•  Quantitative - numerical data

•  Hypothesis - “if..then” statement (an educated guess) : If water is at a high elevation over sea level, then it will boil more quickly, because the atmospheric pressure is lower.

•  Accept or Reject a hypothesis

The Scientific Method

• Variable - the factor being tested

• Control - responds in a predictable way

• Theory - a broad generalization that explains a body of facts or phenomena.

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Scientific Theory and  Scientific Law 

•  A scientific law is a description of an observed phenomenon. Kepler's Laws of Planetary Motion are a good examples. Those laws describe the motions of planets. But they do not explain why they are that way. If all scientists ever did was to formulate scientific laws, then the universe would be very well‐described, but still unexplained and very mysterious. 

A theory is a scientific explanation of an observed phenomenon. Unlike laws, theories actually explain why things are the way they are. Theories are what science is for. If, then, a theory is a scientific explanation of a natural phenomena, ask yourself this: "What part of that definition excludes a theory from being a fact?" The answer is nothing! There is no reason a theory cannot be an actual fact as well. 

Notebook #2 

1. What is the difference between a group and a period on the periodic table?

2. What is the scientific method? 3. What is the difference between

qualitative and quanitative data? 4. Why is a hypothesis used in an

experiment? 5. Why must all science experiments have a

control?

The Metric System • SI Base Units - Standard system of measurement.

• Mass = kilogram (kg)

• Length = meter (m)

• Volume = Liter (L)

• Time = second (s)

• Temperature = Kelvin (K)

• Amount = mole (mol)

Metric prefixes 

Check your work  Converting Units:

1. Write down the word “Given” followed by any information (numbers) given in the problem.

2. Write down a “?” followed by the units to be solved for.

3. Write down the conversion factor.

4. Start with the given and place over 1.

5. Multiply by the conversion factor:

•  The unit in the given is placed in the denominator of the next fraction and the conversion factor is arranged appropriately.

6. Cancel out any units that cancel.

7. Solve the problem with the new units in the answer.

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Notebook #3 - Converting Units: •  How many feet are in 648 inches?

•  Given: 648 inches

•  ? : _____ feet

•  12 inches = 1.0 feet

=

or

x

Notebook #4 Problems: Convert

1.  How many seconds are there in 5.29 min.?

2.  How many quarters are there in 75.0 dollars?

3.  Convert 9.73g to centigrams

4.  Determine how many minutes there are in 3.76 hours.

5.  Calculate the number of centimeters in 0.19 km.

6.  How many kg are in 37 mg.

7.  *How many seconds are there in one year? 1.  317.4 s 2. 300. quarters 3. 973 cg 4. 225.6 min 5. 19000 cm 6. 0.000037 kg 7. 31536000 s

Rules for determining significant figures involving zeros

1. All nonzero digits are significant.

Ex: 38g = 2 sig figs

2. All zeros between two nonzero digits are significant. Ex: 206g = 3 sig figs

3. Zeros at the end of a number without a decimal point present are not significant. Ex: 5210g = 3 sig figs

•  [I.e.: if there is a decimal point then they are significant!]

Rules for determining significant figures involving zeros

4. Zeros at the beginning of a decimal number are not significant.

Ex: .079g = 2 sig figs

5. All zeros to the left of a decimal point are never significant. Ex: 0.22g = 2 sig figs

6. All zeros at the very end of a decimal number are significant.

Ex: 62.0000g = 6 sig figs

Notebook #5 How many significant figures are contained

in each of the following measurements? 1. 37.4 g

2. 6070. Dm

3. 0.00903 km

4. 0.0540 cm

5. 605.03 g

6. 0.8030 L

7. 0.00603 mL

8. 20.00 cm

9. 450 m

10. 0.000070 kg

11. 300. Dm

12. 350.0 K

Rules for Rounding If the digit immediately to the right of the last significant digit you want to keep is:

Greater than 5 → increase by 1

Ex: 43.76 → 43.8 (Round all to 3 digits)

Less than 5 → stay the same

Ex: 43.73 → 43.7

5 followed by a nonzero digit → increase by 1

Ex: 43.751 → 43.8

5 and preceded by odd digit → increase by 1

Ex: 43.75 → 43.8

5 and preceded by even digit → stay the same

Ex: 43.65 → 43.6

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Notebook #6 - Round off each of the following

measurements to the indicated number of significant digits: 1.  35.27 g to 3 sig figs

2.  0.414 kL to 2 sig figs

3.  87.257 dm to 3 sig figs

4.  1.35 K to 2 sig figs

5.  6250 cm to 2 sig figs

6.  6.42 g to 2 sig figs

7.  7.535 mL to 3 sig figs

8.  4.681 cm to 2 sig figs

9.  56.45 kg to 3 sig figs

Interest Grabber Notebook #7

Round off 279.55 m to the indicated number of sig figs

1.  2

2.  3

3.  4

4.  1

Rules for adding/subtracting with sig figs

• When adding and subtracting numbers, the answer must have the same number of decimal places as the original number with the fewest decimal places.

• Example:

•  430.62 m

•  16.1 m

• + 0.5300 m

* least decimal place - ends in the tenth position

447.2500 m = 447.2 m

Rules for multiplying/dividing with sig figs

• When multiplying and dividing, the answer should have the same number of significant digits as the number in the original problem with the least amount of significant digits.

• Example:

750 cm

x 24.32 cm

* least sig figs (2)

18420.00 cm2 = 18000 cm2 (replace the 4 & 2 w/0)

Perform the indicated operation and give the

correct number of sig figs in answer 1.  804.00 g / 20 cm3

2.  9.40 cm x 2.6 cm

3.  4.07 g + 1.863 g

4.  3127.55 cm - 784.2 cm

5.  1.50 g/ 2 cm3

6.  8.08 dm x 5.3200 dm

7.  0.067 mL + 1.01 mL + 2.5 mL

8.  0.08421 g / 0.640 mL

9.  (4.00 m)(0.020 m)(1.57 m)

10.  36.427 m + 12.5 m + 6.33 m

Notebook #8 •  Answer the following questions. Circle final answer!

1.  23.5 m + 1.4643 m + 202.45 m

2.  20.25 g/1.80 mL

3.  Round 54.75 K to the tenths position.

4.  (2.15 m)(0.042 m)

5.  12.7 cm - 0.35 cm

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Answers #1

1.  227.4143m = 227.4 m

2.  11.25g/mL = 11.2 g/mL

3.  54.75K = 54.8 K

4.  0.0903m2 = 0.090 m2

5.  12.35cm = 12.4 cm

Scientific Notation:

1.  Always place the decimal between the 1st and 2nd significant digits.

2.  Drop zeros that are insignificant (only zeros)

3.  Multiply the new number by 10 raised to the exponent, which is the number of times the decimal was moved.

4.  When a decimal is moved to the left the exponent is positive.

•  When a decimal is moved to the right the exponent is negative.

Scientific Notation:

•  Addition/Subtraction with scientific notation must be the same base.

•  Multiplying with scientific notation- add the exponents.

•  Ex: (6.7x103)(4.5x106) = 3.0x1010

•  Dividing with scientific notation – subtract the exponents.

•  Ex: (4.2x108)/(2.1x103) = 2.0x105

•  Problem #5 page 57