Chapter 1: Chemistry in Our Lives

Chemistry

The study of the composition, structure, properties, and reactions of matter

Industries that chem is used for

* Pharmaceutical Industry
* Food Science
* Forensic Sciences
* Medical Practitioner
* Construction + Automotive Industry

How often does chemistry occur

All the time! All around you

Matter

All the substances that make up our world

* Water, air, a glass

What does all matter have?

Mass and Volume

Mass

Amount of matter the substance has

Volume

Space that the matter occupies

Basic air make-up

80% Nitrogen

20% Oxygen

What is the simple N and O called?

Atomic nitrogen and oxygen

What does the N₂ and O₂ mean?

It means that 2 of that atom has bonded together

What is molecular nitrogen?

How nitrogen exists in nature

Is electricity matter?

Nope; the current are not matter

Is car exhaust matter?

Yes; it has many chemicals and stuff

Are atoms matter?

Yes; smallest unit of matter

Is wind matter?

No; it’s formed by interacting matter, but the energy of wind is not matter

Is democracy matter?

No; it doesn’t take up space, except in brains-

Are UV lights matter?

No; any type of visible light isn’t matter = energy

Chemicals

Substances w/ the same composition and properties wherever found

Examples of chemicals

* H₂O = Water
* Au = Gold

Which ones have chemicals?

* Sunlight
* Fruit
* Milk
* Breakfast Cereal

Fruit, Milk, and Breakfast Cereal

\
Sunlight = not matter

Scientific Method

A set of general principals that helps to describe how a scientist thinks

State and describe the steps of the scientific method

1. **Make Observations** about nature and ask questions about those observations
2. **Propose a Hypothesis:** a possible explanation of an observation or law
3. **Perform Experiments:** find relationships between hypothesis and observations
4. **Make a Conclusion** as to whether the hypothesis was true or false after experiments + analysis

What can be done if an observation is always true?

It may be stated as a law

What do you do if your hypothesis and experiment don’t match up?

Revise your hypothesis and try again

What can a conclusion lead to?

A theory

What is the place value of each: 2518.407

2 = thousands

5 = hundeds

1 = tens

8 = ones

4 = tenths

0 = hundredths

7 = thousandths

How do you write a negative number?

With a negative sign → -7

Solve:

3 + 5 =

3 + (-5) =

\-6 + (-8) =

5 - (-7) =

5 x (-4) =

\-7 x (-2) =

\-28/ -2 =

36/-6 =

3 + 5 = **8**

3 + (-5) = **-2**

\-6 + (-8) = **-14**

5 - (-7) = **12**

5 x (-4) = **-20**

\-7 x (-2) = **14**

\-28/ -2 = **14**

36/-6 = **-6**

Percentage Calculation Formula

part / whole(total) x 100 = % of part to the whole

There are 19 red posters, 5 yellow posters, and 8 purple posters. What is the percentage of purple posters?

19 + 5 + 8 = 32

8/32 = 0.25

0\.25 x 100 = 25

\
**25% purple posters**

Solve for x:

\
y = 4x + 7.8

y = 4x + 7.8 → subtract 7.8 y - 7.8 = 4x

y - 7.8 = 4x → divide by 4

\
**x = (y - 7.8)/4**

Solve for T₂:

\
V/T = V₂/T₂

Cross multiply → VT₂ = V₂T

\
divide by V to get T₂ alone

\
T₂ = V₂T/V

What are the parts of a graph

* x-axis = horizontal
* y-axis = vertical
* Title = description of graph
* Points = data values

What is it called when the x and y both increase on a graph?

Direct relationship

What is scientific notation used for?

To write very large and very small numbers

How do you set up scientific notation

co-efficient x power of 10

What does the co-efficient have to be?

Between 1 and 9.999999(repeating)

Write in scientific notation:

2400

0\.00086

569

2400 = 2.4 x 10³

0\.00086 = 8.6 x 10⁻⁴

569 = 5.69 x 10²

In *A Scandal in Bohemia*, Sherlock Holmes receives a mysterious note. He states, "I have no data yet. It is a capital mistake to theorize before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts." What do you think Holmes meant?

Holmes meant…

* Theories should be made to support fact; facts should not be re-written/worded to fit theories
* You cannot make any assumptions before having data/facts to support it

Classify each of the following as an observation, a hypothesis, an experiment, or a conclusion:

a. The bicycle tire is flat

b. If I add air to the bicycle tire, it will expand to the proper size

c . When I added air to the bicycle tire, it was still flat

d . The bicycle tire has a leak in it

a. observation

b. hypothesis

c. experiment

d. conclusion

How will each of the following increase your chance of success in chemistry?

a. self-testing

b. forming a study group

c. reading an assignment before class

a. Assessing yourself can help you locate flaws and areas that you need to study more. It can help with pacing if you plan to time yourself.

\
b. Forming a study group will let you get different perspectives on topics, and may also motivate you to study more. Studying with people can also be a great way to ask questions using the insight of others.

\
c. Reading an assignment before class can help refresh your memory and prepare you for whatever task you need to complete that day.

How will each of the following decrease your chance of success in chemistry?

a. studying only the night before an exam

b. not going to class

c. not practicing the problems in the text

a. Studying only the day before will not help you retain the information nor will it be able to assist you in the future.

\
b. Not going to class can mean you miss important information. You won’t learn anything if you don’t at least show up.

\
c. Not practicing may leave you with unresolved questions that you won’t know you have until you do the problems yourself.