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BELL RINGER. What is a Bell Ringer?. BELL RINGER. What is a Bell Ringer?. -a question that is answered in the beginning of every class. - these NEED to be written in your notebook EVERY day. BELL RINGER. 9/6 What is a Bell Ringer?

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slide1

BELL RINGER

What is a Bell Ringer?

slide2

BELL RINGER

What is a Bell Ringer?

-a question that is answered in the beginning of every class

- these NEED to be written in your notebook EVERY day

slide3

BELL RINGER

9/6

What is a Bell Ringer?

A bell ringer is a question that is answered at the beginning of every class. It must done every day at the beginning of class.

slide4

BELL RINGER

List one thing you learned in school yesterday.

slide5

3 Truths and a Lie about me...

  • I am employed as a beer tester
  • I am a certified cytogeneticist
  • I have coached an NBA player
  • I live in a house with 3 females!
slide7

3 Truths and a Lie about me...

  • I am employed as a beer tester
  • I am a certified cytogeneticist
  • I have coached an NBA player
  • I live in a house with 3 females!
slide9

3 Truths and a Lie about me...

  • I am employed as a beer tester
  • I am a certified cytogeneticist
  • I have coached an NBA player
  • I live in a house with 3 females!
slide12

3 Truths and a Lie about me...

  • I am employed as a beer tester
  • I am a certified cytogeneticist
  • I have coached an NBA player
  • I live in a house with 3 females!
slide14

BELL RINGER

What is Chemistry?

slide15

What is

Chemistry?

slide16

Chemistry:

Two key Questions:

  • Why do materials behave as they do?
    • Overall properties and reactivity
  • How can we take advantage of these properties to something useful?
    • New materials or improve existing materials
    • Pharmaceuticals, fuels, foodstuffs…
slide17

What is Science?

Science is a tool.

Medicine: “I have high cholesterol, what should I do?”

  • Eat Cheerios
  • Consult your best friend.
  • Pray to the god Baa and sacrifice a goat.
  • Take cholesterol lowering medication.
  • Adjust your diet
slide18

Why do you have to

take the core classes?

Math

English

History

Science

making gak
Making Gak

PROBLEM:

How do you make GAK, efficiently?

HYPOTHESIS:

= your recipe (amounts of ingredients)

EXPERIMENT:

= order of mixing, and how it was mixed

CONCLUSION:

Explain your results

slide21

BELL RINGER

What is the scientific method?

slide23

Gak Lab

Finish

goals
Goals

The Last Lecture

slide26

BELL RINGER

What are these?

slide27

model

test

The Scientific Method

  • Observe an event.
  • Develop a model (or hypothesis) which makes a prediction.
  • Test the prediction.
  • Observe the result.
  • Make your conclusion
  • Revise the hypothesis.
  • Repeat as needed.
  • A successful hypothesis becomes a ScientificTheory.
medical science
Medical Science

Patient has high cholesterol

Certain chemicals may dissolve cholesterol deposits.

Give 100 patients these chemicals, give 100 patients placebo.

Same number lower their cholesterol as placebo patients.

Try different combo of chemicals.

Re-run medical test. Observe results.

Lipitor reduces cholesterol.

everyday science
Everyday Science

Engine won’t turn over.

Predict battery is dead.

Replace battery.

Engine now turns over.

Not needed.

Not needed.

Cars won’t work without a fully charged battery.

everyday science1
Everyday Science

Try a tomato sauce.

Heat pot of tomato sauce.

Taste the sauce - bland.

Use tomato sauce and garlic!

Add garlic, taste - not so bland.

The Final Recipe.

making gak1
Making Gak

PROBLEM:

How do you make GAK, efficiently?

HYPOTHESIS:

= your recipe (amounts of ingredients)

EXPERIMENT:

= order of mixing, and how it was mixed

CONCLUSION:

Explain your results

slide32

BELL RINGER

List, in order, the steps of the scientific method.

slide33

You have $7.25 in your pocket in quarters. How many quarters do you have?

1 dollar

7.25 dollars

4 quarters

X

=

1

= 29 quarters

slide35

Chemistry In Action

On 9/23/99, $125,000,000 Mars Climate Orbiter entered Mar’s atmosphere 100 km lower than planned and was destroyed by heat.

1 lb = 1 N

1 lb = 4.45 N

“This is going to be the cautionary tale that will be embedded into introduction to the metric system in elementary school, high school, and college science courses till the end of time.”

slide36

BELL RINGER

  • Perform the following conversions -
  • 1.76 kg = ____________ dg
  • 0.0036 mm = _________ m
  • 5.2 x 10-2L = _________ cL
slide37

Observation:

Inference Lab

counting significant figures
Counting Significant Figures

RULE 1. All non-zero digits in a measured number are significant. Only a zero could indicate that rounding occurred.

Number of Significant Figures

38.15 cm 4

5.6 ft 2

65.6 lb ___

122.55 m___

zeros in front
Zeros in Front

RULE 2. Leading zeros in decimal numbers are NOT significant.

Number of Significant Figures

0.008 mm 1

0.0156 oz 3

0.0042 lb ____

0.000262 mL ____

sandwiched zeros
Sandwiched Zeros

RULE 3. Zeros between nonzero numbers are significant. (They can not be rounded unless they are on an end of a number.)

Number of Significant Figures

50.8 mm 3

2001 min 4

0.702 lb ____

0.00405 m ____

trailing zeros
Trailing Zeros

RULE 4. Trailing zeros in numbers without decimals are NOT significant. They are only serving as place holders.

Number of Significant Figures

25,000 in 2

200. yr 3

48,600 gal ____

25,005,000 g ____

slide43

BELL RINGER

What are the volumes in the cylinders on the right?

Remember Sig Fig’s

A

B

C

significant figures
Significant Figures
  • The numbers reported in a measurement are limited by the measuring tool
  • Significant figures in a measurement include the known digits plus one estimated digit
significant numbers in calculations
Significant Numbers in Calculations
  • A calculated answer cannot be more precise than the measuring tool.
  • A calculated answer must be rounded to match the least precise measurement.
adding and subtracting
Adding and Subtracting

Only concerned with numbers AFTER the decimal point. Round to the least precise measurement.

25.2one decimal place

+ 1.34two decimal places

26.54

answer 26.5one decimal place

learning check
Learning Check

In each calculation, round the answer to the correct number of significant figures.

A. 235.05 + 19.6 + 2.1 =

1) 256.75 2) 256.8 3) 257

B. 58.925 - 18.2 =

1) 40.725 2) 40.73 3) 40.7

multiplying and dividing
Multiplying and Dividing

Round (or add zeros) to the calculated answer until you have the same number of significant figures as the measurement with the fewest significant figures.

learning check1
Learning Check

A. 2.19 X 4.2 =

1) 9 2) 9.2 3) 9.198

B. 4.311 ÷ 0.07 =

1)61.582) 62 3) 60

C. 2.54 X 0.0028 =

0.0105 X 0.060

1) 11.3 2) 11 3) 0.041

slide50

Theory: A Unifying Principle that explains Facts and Laws

    • Theories are not hypothesis
    • Continuously revised as new data obtained
    • Theory of Evolution

Scientific Laws and Theories

  • Law: Repeatedly tested hypothesis that has not been contradicted
    • Law of Gravity
slide51

Qualitative

    • Red
    • Far from Earth
    • Microscopic
    • Hot
  • Quantitative
    • 700nm wavelength
    • 300 million light yr
    • Smaller than 1 μm
    • 350 °C

Important terms/considerations

for describing matter

  • Quantitative vs. Qualitative descriptions
  • Qualitative
    • Subjective
    • Interpretations
    • “Brittany is fast”
  • Quantitative
    • Objective
    • Measurable
    • “Brittany’s 100m time is 9.8 sec
slide52

Important terms/considerations

for describing matter

  • Precision vs. Accuracy
  • Precise
    • Repeatability of a measurement
    • Does not take into account the real or true value
  • Accurate
    • Agreement between the measurement and the true or correct value
    • ‘Correct’
slide53

Can you hit the bull's-eye?

Three targets with three arrows each to shoot.

How do they compare?

Both accurate and precise

Precise but not accurate

Neither accurate nor precise

Can you define accuracy and precision?

slide54

Precision vs Accuracy

Not accurate,

Not precise

Not accurate,

Precise

Accurate,

Precise

slide55

Avg.

1.01 g

2.601265g

1.01326g

1.00 g

Precision vs Accuracy

Mass of a paperclip = 1.0003 g

Group 4

1. Which group(s) are most accurate?

2. Which group(s) are most precise?

3. Which group is the most accurate and precise?

Group 3

Group 3

slide56

Precision vs Accuracy

Which ruler can be most precise?

Accurate?

Ruler A

Ruler B

Ruler C

slide57

Precision vs Accuracy

Which clock can be most precise?

measurement

For example, at one time the standard for length was the king’s foot. What are some problems with this standard?

Measurement

What is our system of measurement based upon?

slide59

1

=

1902 km

BELL RINGER

The distance between Los Angeles and Denver is 1182 miles. How many kilometers is this?

1km = 3281 ft

1182 miles

1 km

5280 ft

x

x

1 mile

3281 ft

=

6240960 km

3281

stating a measurement
Stating a Measurement

In every measurement there is a

  • Number followed by a
  • Unit from a measuring device

The number should also be as precise as the measurement!

** Without a unit – your answer is _________!!!!!!!

NAKED

You have naked numbers??? Oh, the horror!

slide61

This ruler can measure to the 10th of a mm

mm. marks

A metric ruler

cm. marks

Measuring

Significant Figures

slide62

Estimating the last digit in a measurement

You might estimate the end of the cylinder to be half-way between the lines or 0.05 cm. This digit must be included in the measurement.

slide63

Estimating the last digit in a measurement

This measurement should be read as 4.95 cm. This measurement has 3 significant figures.

slide64

Reading a metric ruler correctly:

This point can be read as 1.65 cm. or 16.5 mm.

slide65

Reading a metric ruler correctly:

This point can be read as 6.70 cm. or 67.0 mm.

slide66

Read the cylinder correctly:

We know it is between 35 and 40

We know it is between 36 and 37

Should be read as:

36.4 ml

slide67

Read the cylinder correctly:

We know it is between 6 and 8

36

Should be read as:

6.62 ml

slide68

1

=

4.96 x 10-4 weeks

BELL RINGER

Convert 300. seconds to weeks.

300. sec

1 min

1 hour

1 day

x

x

x

60 sec

60 min

24 hrs.

1 week

x

7 days

what is scientific notation
What is Scientific Notation?
  • Scientific notation is a way of expressing really big numbers or really small numbers.
  • It is most often used in “scientific” calculations where the analysis must be very precise.
  • For very large and very small numbers, scientific notation is more concise.
scientific notation consists of two parts
Scientific notation consists of two parts:
  • A number between 1 and 9
  • A power of 10
  • N x 10x
to change standard form to scientific notation
To change standard form to scientific notation…
  • If you make the numbersmaller, then you have to make the exponent larger.
  • If you make the number larger, then you have to make the exponent smaller.
example
Example
  • Given: 289,800,000
  • Use: 2.898 (moved 8 places)
  • Answer:2.898 x 108
  • Given: 0.000567
  • Use: 5.67 (moved 4 places)
  • Answer:5.67 x 10-4
to change scientific notation to standard form
To change scientific notation to standard form…
  • Simply move the decimal point to the right for positive exponent 10.
  • Move the decimal point to the left for negative exponent 10.

(Use zeros to fill in places.)

example1
Example
  • Given: 5.093 x 106
  • Answer: 5,093,000 (moved 6 places to the right)
  • Given: 1.976 x 10-4
  • Answer: 0.0001976 (moved 4 places to the left)
practice

4.06 x 105

3.87 x 10-3

3.00 x 109

2.00 x 100

4.78 x 10-1

Practice

Express these numbers in Scientific Notation:

(Round to 3 significant digits)

405789

0.003872

3000000000

2

0.478260

temperature conversions
Temperature Conversions

A person with hypothermia has a body temperature of 29.1°C. What is the body temperature in K?

K = ˚C + 273

K = 29.1˚C + 273

K = 302.1

slide77

1

=

1.2 x 105 sec

BELL RINGER

How many seconds are in 1.4 days?

1.4 days

24 hours

60 min.

60 sec

x

x

x

1 day

1 hour

1 min.

120960 sec

=

1

bell ringer
Bell Ringer

How many feet in 0.50 kilometers? Remember Sig Figs

temperature scales

Anders Celsius

1701-1744

Lord Kelvin

(William Thomson)

1824-1907

Temperature Scales
  • Fahrenheit
  • Celsius
  • Kelvin
temperature scales1

212 ˚F

100 ˚C

373 K

100 K

180˚F

100˚C

32 ˚F

0 ˚C

273 K

Temperature Scales

Fahrenheit

Celsius

Kelvin

Boiling point of water

Freezing point of water

Notice that 1 kelvin = 1 degree Celsius

calculations using temperature
Calculations Using Temperature

Generally require temp’s in kelvins

K = ˚C + 273

Body temp =

37 ˚C + 273

= 310 K

Liquid nitrogen = -196 ˚C

+ 273 =

77 K

density an important and useful physical property

Platinum

Mercury

Aluminum

DENSITY - an important and useful physical property

D =

13.6 g/cm3

21.5 g/cm3

2.7 g/cm3

slide83
ProblemA piece of copper has a mass of 57.54 g. It is 9.36 cm long, 7.23 cm wide, and 0.95 mm thick. Calculate density (g/cm3).
slide84
Strategy

1. Get dimensions in common units.

2. Calculate volume in cubic centimeters.

3. Calculate the density.

slide85
SOLUTION

1. Get dimensions in common units.

2. Calculate volume in cubic centimeters.

3. Calculate the density.

(9.36 cm)(7.23 cm)(0.095 cm) = 6.4 cm3

Note only 2 significant figures in the answer!

bell ringer1
Bell Ringer

What is the length of the green line?

. l3. . . . I . . . . I4 . . . . I . . . . I5. . cm

you need to know for the exam
You need to know for the exam
  • Precision & Accuracy
  • Element Symbols 1-18
  • Significant Digits
  • Metric System
  • Scientific Method
  • Scientific notation
  • Conversions
  • What is Chemistry
  • Labs that we have done so far
bell ringer2
Bell Ringer

What is Chemistry?

How many yards in a mile?

slide90

BELL RINGER

BELL RINGER

What is the name of this flask?

slide91

1

=

1.31 x 10-5 sec

BELL RINGER

What is 7.9 seconds in weeks?

7.9 sec

1 min

1 hour

1 day

x

x

x

60 sec

60 min

24 hours

1 week

x

7 day