You may be thinking, why I am reviewing this concept? Well here are eight words that sum up why this is on the page: Chemistry is a mixture of Mathematics and Science. Scientific Notation is an amazing thing that is easy but can be challenging if you do not know where do place the decimals or just need a refresher.

Example:

Turn 2,700,000,000 into scientific notation.

First Step: I recommend putting a decimal at the end of the number because it will be a place maker for what we need in order to convert this whole number into scientific notation.

2,700,000,000.00

Second Step: Move the decimal to where there is not zero. As a result, move the decimal nine places to the left. This may be confusing because there 2 and 7. You want the decimal to be in between 2 and 7 because the zeros will transform into our ten to the power.

2.7

You may be wondering where are the zeros; this brings me to my next set.

Third Step: Turn those zeros into the ten to the power (i.e 10^2). The number of decimal places we moved will be our power. We moved nine decimal places in order to reach 2.7 which will be our power. This just means that the decimals places will now turn into 10^9. This is a great skill to know because in stoichiometry, Avagrado's number is in this form. Also, putting your numbers in this form will make your life ten times easier when utilizing a calculator.

Final Answer: 2.7*10^9

Practice Problems: If you need more help please contact me. My contact information is at the bottom!

1.) Turn 2,841,000,000 into scientific notation.

2.) Turn 0.0000000193 into scientific notation. (Remember the power will be negative) (Example: 10^-3)

Answer for number 1:

2.841*10^9

Answer number 2:

1.93*10^-8

Challenge if you are not struggling as much!

Turn 2.3*10^6 into a whole number!

Answer for challenge:

2,300,000

This is another important topic that you should familiarize yourself with because this rounding method will come in handy when you are being tested for finals in high school or college.

This is a simple definition for significant figures (Trust me, this will be one of your best friends in chemistry): You must count everything EXCEPT for the zeros that are at the beginning of a number and zeroes at the end of a whole number.

What does that mean? I am glad that you asked. Here are some examples with explanations that elaborate on this definitions.

Example 1:

How many sig. figs does the number 205 have? It has three because there are no zeros at the beginning or end of this whole number. Therefore, the middle zero counts. Do not be fooled! Always count the zero if it is in between numbers from 1-9.

Example 2:

How many sig. figs does 10005 have? You guess it! It has five sig. figs because the same principal applies. It is a whole number with exceptions. Remember these zeros are not at the beginning or end of a whole number.

Example 3:

Here is a more difficult problem. How many sig. figs does 0.00250 have? It only has three sig figs. We never count zeros that are at the beginning. However, you may be thinking why does the last zero count? It counts because this is not a whole number; this number is a decimal.

Example 4:

You do not believe me. Here is another example. How many sig. figs does 1000 have? This number only has 1 sig. fig because this is a whole number. As a result, we do not count anything after 1 because it has three zeros that do not count.

Example 5: Another tricky example

How many sig. figs does 9000.0 have? It has five sig. figs because of the decimal. With a decimal being added, this is not a whole number anyone more. Therefore, we count the zeros after.

More practice:

1.) How many sig. figs does 0.005 have?

2.) How many sig. figs does 3,000,005,000 have?

Answers/Explanations:

Answer 1: This number only has 1 sig. fig because anything in front of a whole number or decimal does not count if it is a zero. This rule causes the three zeros to not count.

Answer 2: This number has 7 sig. figs. We must cancel the last three sig figs because those are the last zeros of our number, resulting in the canceling of the last three zeros.

Metric systems are crucial in science but you may need a refresher. I will be providing you with some examples with some explanations.

The Best Way To Remember Metric Systems:

King Henry Drank Milk During Class On Monday

K=Kilo

H=Hecto

D=Deca

M=Meter

D=Deci

C=Centi

M=Mili

You can use this acronym as a number line to convert any measurements of unit within the saying!

Examples:

1.) Convert 2.8 hm into dm.

2.) Convert 25.96 dm to km.

3.) Convert 0.003 dam to mm.

4.) Convert 6852 to dm.

5.) Convert 1.39 km into mm.

Answers:

1.) 2800 dm

2.) 0.002596 km

3.) 30 mm

4.) 68.52

5.) 1,390,000

I know you learned this in middle school but it is beneficial that you review you this section because this is discussed in chemistry!

Matter: It is anything that takes up space and has mass.

Examples: Particles of matter are always moving! They are bouncing, speeding, etc!

We have four important states of matter!

Solids:

• They have very low kinetic energy because the particles in a solid are compressed heavily. They do not move around as much!

• Solids are in a fixed shaped meaning that they do not move around as much!

• Also, solids have a fixed volume!

Liquids

• As I mentioned before, liquids have low kinetic because they move around but do set around together.

• Moreover, liquids have a variable shape in their particles.

• In addition, liquids have a fixed volume.

Gases

• Gases have high kinetic energy because the particles are moving around rapidly. They spread out in order to fill the space they are in,

• Gases have a variable shape.

• Furthermore, gases have a variable volume.

Plasma

• Plasma has very high kinetic energy because the particles are colliding with enough energy to break into charged particles.

• It is gas-like!

• Moreover it has a variable shape and volume!

Pure Substances!

Elements:

• They are composed identical atoms. They are in the periodic table!

• Examples: Copper (Cu), Aluminum (Al), Hydrogen gas (H2), Oxygen gas (O2)

Compounds

• Compounds are two or more elements in a fixed ratio. The properties differentiate from those of the individuals elements on the periodic table. They are not singular and are attached to something else.

• Examples: Table salts (NaCl), Water (H20), Sulphuric Acid (H2SO4), Ammonia (NH3)

Mixtures:

1. In mixtures there are two or more substances that are utilized when classifying them.

2. Homogenous: They are solutions, very small/tiny particles, and these particles generally do not settle.

3. Heterogenous: They are solutions that collide, are medium sized particles, and their particles never settle.

Examples of Homogenous mixtures: rubbing alcohol, steel, air, rain, and much more.

Example of Heterogenous mixtures: milk, ice in a beverage, soil, and much more.

Suspension:

Suspension is heterogenous, has large particles, and the particles settle.

Examples of Suspension: Oil in sand, water, etc. Fresh squeeze lemonade.

Density is important to know because it will appear in your first unit of chemistry!

Density, in a nutshell, determines how much matter an object has which allows us to determine if an object will float or sink.

Some useful equations to note:

1. Density=Mass/Volume

2. Mass=Density*Volume

3. Volume=Mass/Density

If the density of an object is greater than one it will sink.

If the density of an object is less than one it will float.

Volume: cm^3 or ml (1 ml= 1cm^3)

Mass: grams in this version

l*w*h=cm^3

Examples using each equation:

If an object has the mass of 2.0 grams and a volume of 20 millimeters, what is the density?

Remember plug and chug!

Mass= 2.0 grams

Volume= 20 millimeters

Density=?

Density= 2 grams/20 millimeters

Density= 0.1 g/ml

If an object has a density of 1.06 g/cm^3 and a volume of 0.3 cm^3, what is the mass of the object?

Remember plug and chug!

Mass=?

Volume= 0.3 cm^3

Density+ 1.06 g/cm^3

Mass=1.06g/cm^3*0.3 cm^3

Mass=0.318

If an object has a density of 0.463 g/ml and a mass of 12.33 grams, what is the volume?

Mass= 12.33 grams

Volume=?

Density= 0.463 g/ml

Volume=12.33g/0.463g/ml

Volume= 26.63 ml

The equation needed to find percent error:

accepted-experimental/accepted*100= percent error

A student measured the temperature of boiling water (H2O) to be 97.5 C. What is the percent error?

100-97.5C/100*100=2.5%

A student estimates a mass of a pig to be 325 grams but the mass of the pig is actually 342 grams. What is the percent error?

342-325/342*100= 4.97%

Additional Examples:

Actual: 6.25 grams Experimental: 6.00

6.25-6.00/6.25*100= 4.00%

Actual: 2.16 Experimental: 2.04

2.16-2.04/2.16*100= 5.60%

Actual: 92 Experimental: 87

92-87/92*100= 5.4%

Ionic Bonds---> one atom donates an electron to another! (Held together by electrostatic attraction)

Covalent Bonds-----> atoms share an electrons

NaCl-----> Sodium Chloride

BaO------> Barium Oxide

Ag3N-----> Silver (I) Nitride

Al2S3-----> Aluminum Sulfide

BaI2-------> Barium Iodide

K3P-------> Potassium Phosphide

LiCl--------> Lithium Chloride

Ca3N2-----> Calcium Chloride

Transition Elements:

Lead (IV) Chloride

PbCl4

Iron (II) Chloride

FeCl2

Copper Iodide

CuI2

Polyatomic Ions: (Examples) *Note: I would remember these because you will be tested a lot on this!:)*

Nh4+= Ammonium

H3O+= Hydronium

ClO4-Perchlorate

ClO3-Cholorate

ClO2-Chlorite

ClO-Hypochlorite

NaClO3----> Sodium Chlorate

NaClo2-----> Sodium Chlorite

NaCl--------> Sodium Chloride

I will post a sheet regarding key polyatomic ions!:)

These are just a few that I would recommend skimming before you start the unit!

Proton:

Mass=1 amu

Positive charge

Neutron:

Mass= 1 amu

No charge (Neutral)

Electron:

Mass= insignificant

Negative charge

Mass of an atom= Mass of all protons and neutrons

Rows that go across: Periods

Groups/Families: Columns (Those go up and down)

Mass number= Mass of protons and neutrons

# of Neutrons= Mass of #- Atomic #

Examples:

Element Group # Period Atomic#

Titanium 4/4 B 4 22

Carbon 14/4 A 2 6

Sulfur 16/6 A 3 16

Helium 18/8 A 1 2

What is the mass number of titanium? Protons? Neutrons? Electrons?

Mass= 48

Protons= 22

Neutrons= 26

Electrons= 22

What is the mass number of carbon? Protons? Neutrons? Electrons?

Mass= 12

Protons= 6

Electrons= 6

Neutrons= 6

What is the mass number sulfur? Protons? Neutrons? Electrons?

Mass= 32

Protons=16

Neutrons= 16

Electrons= 16

What is the mass number of helium? Protons? Neutrons? Electrons?

Mass= 4

Protons= 2

Neutrons= 2

Electrons= 2

Hi there! I know , memorizing 103 elements can be tedious but it will give you a great advantage when it comes your chemistry classes. You don't have to keep pulling out your periodic table and some teachers don't allow the use of it, so mine as well learn it!

Here are some of my best tips when it comes to memorizing the whole table!

1. Assign yourself at least 20 minutes of your day to memorize or practicing your periodic table.

2. Print or use a digital copy of a periodic table that has has color sections based on the element series, type of metal, and much more!

Here is a good one: https://ptable.com/print/periodic-table.pdf

3. Divide your periodic table into 9 rows! You want to memorize one row every 2 days or week. This will help you retain the information quickly!

4. First, memorize element symbol. (Example: H= Hydrogen) This is key because if you are thrown a problem and you do not know the symbol; you will be in big trouble.

5. After you memorize the symbols, start memorizing their masses. It is crucial that you understand the atomic mass of each element in order to solve stoichiometry, gas laws, etc. (This will be the hardest section but I recommend that you round it! If you know the rounding of the atomic mass than you will get closer to memorizing the exact value)

6. After you memorize the atomic mass, you will understand their placements on the table, you can begin practicing the grouping of each element. (Example: What metal or gas is Hydrogen? A) Alkali Metal B)Alkaline Earth Metal C) Transition Metal D.) Basic Metal E) Halogen

7. All of this memorization should be done after you know what columns, families, and much more. Once you know these things, this will serve you greatly on remembering the entire periodic table. TRUST ME! It is a process but you will remember it.:)

The mole is an important in chemistry! If anyone ever asks you for your number, just give them this number: 6.02*10^23 (trust, it works every time). This is Avogadro's number and crucial when it comes to converting grams to moles to atoms and vice versa.

Examples of when Avogadro's number is utilizes:

How many moles does Iron have if it has 3.54*10^26 atoms?

1 mol

3.54*10^26 atoms ----------------- = 588 moles

6.02 *10^23

How many molecules does carbon have if it weighs 29.4 grams?

1 mols 6.02*10^23 molecules

29.4 grams ----------------- ----------------------------- = 1/47*10^24 molecules of Carbon

12 grams 1 mole

These are examples but you get the point! This is a significant number and knowing this number will help your chemistry class!

Let's get to learn the basics!

• Temperature is a big benefactor. Vibration and Particle Movement depends on temperature. Temperature is independent!

• KE average and Temperature are direct proportions. If one increases, the other must increase as well!

• Kelvin will be a unit you will use for gas laws! You will have to convert Celsius to Kelvins when doing so! Conversion for this: Temperature (K)=Temperature (C) +273.15!

• Absolute Zero= -273 degrees Celsius. This is where particle movement "stops"

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