H Chemistry Fall Final

Unit 1:

Physical Properties:

• It is experienced with normal senses such as touch, sight, and hearing.

  • Taste isn't considered because it is such a basic test for our environment that even babies do it and is technically a chemical experiment.

  • Smell isn't based on the physical construction of a property.

• What temperature substance boils and melts

  • Example: water freezes at 32 degrees F/ 0 degrees C and water boils at 100 degrees C/ 212 degrees F.

  • Water is THE MOST IMPORTANT COMPOUND TO EXIST because it determines whether life can survive in certain places.

• Different substances have different freezing and boiling temperatures.

Chemical Properties:

• A substance's ability to form new substances when…

  • Heated

  • Exposed to other substances

• If nothing happens, that's a chemical property.

Physical Change:

• Change in the state of matter

  • Substance is same in composition but changes state of matter.

    • Substance doesn't change chemically but is physically altered.

  • Particles physically change location between them.

    • Solid:

    • Liquid:

    • Gas:

  • Substance composition is unchanged

  • ALWAYS reversible

Chemical Change:

• Change in components of a substance 

• Signs of Chemical Change:

  • Heat/temperature change

    • I.e. eating a slice of pizza --> turns to calories

  • Light production

  • Smell change/taste change

  • Color change

Mixture:

• Material of different ingredients

Alloy:

• Mixture of metals

  • Examples: steel (made up of iron, carbon, nickel, chromium depending on the usage of it), bronze (copper and tin), brass.

Pure substance:

• Same mixture composition of throughout

Homogenous mixture (has basically the same definition as a pure substance, but looks the same throughout):

• Examples: milk, air, tap water, gasoline, saltwater, and rubbing alcohol.

Solution: liquid or gas homogenous mixture (a lot of the examples from above)

Heterogenous mixture:

• Mixture with variable/changing composition

• Examples: trail mix, salad, sand, granite, Chipotle bowl, gravel, certain cereals, orange juice, seasonings, protein shake, and salad dressings.

Shorthand number format for very large or small values.

• Uses x 10 ^ n

• #.## x 10 ^ n

• 3210000.0 x 10 ^ 0 = 3.21 x 10 ^ 6

• 0.00000321 x 10 ^ 0 = 3.21 10 ^ -6

Kelvin to Celsius:

C = K - 273

F to C:

F = 9/5C + 32

Matter: physical "stuff" that makes up the universe

• Two criteria that all physical matter fulfills

  • It has mass (amount of material [measured in grams/kilograms])

  • It takes up volume (the space that the matter occupies [measured in liters])

Atoms: all matter is made of basic pieces called atoms

Atoms make up EVERYTHING!!

Compounds: substances made by bonding atoms together in specific ways

• Made from different elements bonded together

Molecules: atoms that are stuck together

• A broader categorization than compounds

Element: atoms of the same type (i.e. iodine, fluorine, potassium, iron, etc.)

• We know they are the same type because same elements have identical traits

  • Sometimes, these are bonded together

Solid: a rigid substance with a fixed shape and volume

• Examples:

  • Ice

  • Pencil

  • Table

Liquid: substance of definite volume but takes the shape of the container

• Examples:

  • Water

  • Apple Juice

Gas: Matter that has neither fixed volume nor fixed shapes

• Examples:

  • Helium

  • Steam

• Plasma: charged gas that is produced at extremely high temperatures

  • A subcategory of gas

Bose-Einsteinium condensate: weird fluid produced at really cold temperatures

• If you were to pour it in a cup, it flows vertically and climbs up the wall of the cup.

1. Zeros BEFORE nonzero digits are NOT significant

   1. 0.00025 has two significant figures, the 2 & 5

2. Zeros BETWEEN digits ARE significant

   1. 0.000205 has three significant figures

3. Zeros to the right WITH A DECIMAL are significant

   1. 0.000250 has three sigfigs

   2. 2500. has four sigfigs because of the decimal

   3. 2500 has two sigfigs because of no decimal

Unit 2:

Contributing mass = mass # of the element x percent abundance / 100

Elements are the basic building blocks of all matter.

Each element is unique from other elements.

Elements combine into compounds

Letters ---> words                                                 Elements ---> compounds

Elements use symbols to abbreviate for their names

• First letter of symbol is always capital

• Second letter is lower case

• Example: Ni for nickel. NOT NI

Some element symbols don't match current names because they're based off of older names.

• Example: lead was plumbum so its symbol is Pb

groups/families go up to down

periods go right to left

all semi-metals touch the thick black line on the right of the periodic table, except for aluminum, which is a metal

all non-metals are above/to the right of the thick black line, except for hydrogen (also a non-metal)

1A: Alkali metals

2A: Alkaline earth metals

7A: halogens

8A: noble gases

Diatomic elements can NOT be on their own

• H

• O

• F

• Br

• I

• N

• Cl

Proton: 1 amu (atomic mass unit) (positive)

Neutron: 1 amu (neutral)

Electron:  amu (practically 0 amu) (negative)

Orbit keeps moon from crashing into the planet

• Motion goes around fast enough so it slides 90 degrees around the planet.

• Hence, electron goes so fast it never crashes into speed of nucleus

Atomic Mass = protons + neutrons (contain mass of atom)

Atomic Number = protons: identifies an element

Isotopes: Same elements with different atomic masses

• Sodium-22               : 11 protons & 11 neutrons

• Sodium-23               : 11 protons & 12 neutrons

Ion: an atom w/ charge

• Charge = proton - electron

• Occurs when electrons are gained or lost

Atomic number = number of protons

Atomic Mass = proton + neutron

Charge = protons - electrons

Ions are atoms that gain or lose electrons

• Ions are NOT produced from a change in protons

Cations: positive ions due to losing electrons

Anions: negative ions due to gaining electrons

Ions of opposite charges are attracted to each other

Ions of same charges repel each other

Ions will attract opposite charges until the sum of all charges equal zero

• Example: Ca⁺² will attract 2 F^-

• Ca⁺² + 2 F^- ----> CaF2

Ionic bond: force holding ions together when oppositely charged ions are attracted to each other.

Ionic compound: a compound that is formed ionically

Practice: Form all compound combinations

Cation is named first and uses the whole name

Anion is named last

• Use only the first "syllable"

  • Cut off before the 2nd vowel

  • Ends w/ -ide

  • I.e. chlorine ---> chloride, so NaCl = sodium chloride

  • AlO = aluminum oxide

  • Phosphorus ---> phosphide

  • Lithium fluoride ---> LiF

A category of reactive substances

Has "H" in front of its formula

Binary Acid (HX)

• Hydro-x-ic acid

• HCl:

  • Hydrochloric acid

• HF:

  • Hydrofluoric acid

Oxyacids (HXO_n):

• -ite

  • X-ous acid

  • HClO₂ <--- chlorite

    • Chlorous acid

• -ate

  • X-ic acid

  • HClO₃ <--- chlorate

    • Chloric acid

• H₂SO₃:

  • Sulfurous acid

• Phosphoric acid:

  • H₃PO₄

• However negative the anion is, that’s how many ions you attach to it.

Percent composition:

• % of individual element mass in whole compound

• H₂O has a molar mass of 1 g/mol

• % composition = ([mass of element]/[total molar mass]) x 100

Simplest ratio of elements in a compound

Finding Empirical Formula:

1. Mass of each element

2. Convert mass into moles of each element (divide by atomic mass)

3. Select smallest mole count

4. Divide ALL element mole counts by smallest mole count found in step 3

Molecular formula is the actual composition of elements in a compound.

• Multiples of empirical formula

• Empirical mass: mass of empirical formula

• Molecular mass

• Molar mass

• Molecular weight

• Molar mass/empirical mass = formula multiplier

Unit 3:

Signs of Chemical Reaction:

• Changes in color

• Light production

• Change in state of matter

• Heat exchanged (heat released or absorbed)

Chemical equations: a representation of what happens during a chemical change

Chemical change: a rearrangement of the elements present

• No atoms are lost or gained

Chemical Equation: represents the parts of a reaction

• Reactants -> products

• Food -> poop

Law of Conservation of Matter

"Matter cannot be created or destroyed, only rearranged."

Elements can't be added or removed, BUT you can change their RATIOS

_C₂H₆ + _O₂ ----------->  _CO₂ + _H₂O = COMBUSTION REACTION

H2O ALWAYS NEEDS TO HAVE AN EVEN NUMBER BEFORE IT

Dissolving Ionic Compounds in water: Water breaks apart Ionic Compounds into its ions (water is the universal solvent)

Precipitate: A solid that forms from new ionic compound that is INSOLUBLE

• CAN also be other states of matter

Spectator Ions: Ions that do not create precipitate/solids

      They are not part of the reaction

Net Ionic Equation: Removes spectator ions from the equation altogether.

Electrolytes: an aqueous solution of dissolved ions

• Because ions are dissolved, they are freed to move

  • Because the ions are freed to move, they can conduct electricity.

  • Is a CONDUCTIVE SOLUTION

• Sweat is ion solution coming out of your pores, which reduces your ability to conduct electricity and results in muscle spasms (can either be muscle cramps or heart attack).

Acid dissociation:

• HX _(aq)---> H⁺_(aq) + X^-_(aq)

• H₂SO_{4 (aq)}---> 2H⁺_(aq) + SO₄^-_(aq)

Base: are solutions that contain the hydroxide ion

Acid-base neutralization:

Acid + Base ---> salt + water

HX + YOH ---> YX + H₂O (H-OH)

Synthesis: two different elements combined into one to make a compound

A+B —> AB

Decomposition: tearing apart

 AB —> A + B

Single replacement: a single thing is being swapped out

 AB + C —> AC + B

Double replacement: two things are being swapped out

AB + CD —> AC + BD

Combustion: burning; not always an explosion

 _C₂H₆ + _O₂ ----------->  _CO₂ + _H₂O

H2O ALWAYS NEEDS TO HAVE AN EVEN NUMBER BEFORE IT

Chemical reactions take place PROPORTIONALLY by number of particles.

Because changes in substances are proportional, we can predict amount of change or how much product is made.

Reactants: What is used in the reaction

Products: What is made in the reaction

Chemical Reaction: a simple equation representing the ratios of substances in a chemical reaction

Reactants --> Products

Mole Ratio: the ratio that shows the proportional change between compounds

• Uses the COEFFICIENTS in a balanced equation

Eg. 4 mol CO₂/ 6 mol O₂

Mole ratio is used in stoichiometry to convert between substances

Amount of product made is dependent on whichever reactant gets used up first

2 slices of bread + 1 slice of turkey --> 1 sandwich

Your fridge holds 7 slices of bread and 10 slices of turkey. Which is the limiting reactant? How can you tell?

You compare how much product each reactant can make. Whichever makes less is the limiting reactant.

Actual: amount of product obtained from experiment

Theoretical: amount predicted from calculation of starting amounts

% yield = (actual yield / theoretical yield) x 100