- Made of two or more metals, or a metal and a nonmetal (must be solid at room temp) - Melt solid components and allow to mix/dissolve - To identify must know types of metal/solid used.

Chemistry FINAL!!!!! Flashcards by Alonna DePalma

Mulipying and dividing Sigfigs

Do not round until the end
Count number of sigfigs in each number
Find the number with the lowest amount of sigfigs.

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Sigfig rules

All non zero digits are significant.
Zeros between sigfigs are significant. EX (0.504)
Leading zeros are not significant
Trailing zeros after a decimal place are significant EX.(4.0)
97(2) and 97.00(4) are different
Trailing zeros can be significant, if a deciaml is shown.
Exact numbers have an infinite amount of sigfigs.
All digits that compromis “n” are significant Ex. (10^x is not significant).

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Adding and subtracting sigfigs

Do not round until the end
Find number with least amount of decimal places.

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Density equation

Density = Mass divided by volume

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Physical property

Characteristic of a substance that can be observed without changing it to something else.

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Chemical property

Characteristic of a substance that can only be observed if it is changing

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Extensive property

Change based on how much matter we have
Ex. Volume, shape, mass

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Intensive property

Stays the same no matter how much matter we have
Ex. Color,texture, boiling/freezing point, density

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Mixture

Made of two or more pure substances

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Element

Substances that cannot be seperated into simpler substances by chemical means

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Compound

A pure substance composed of two or more elements whose composition is constant

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Law of definite proportions

A pure substance will contain same elements in same proportions by mass

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Alloy

Made of two or more metals, or a metal and a nonmetal (must be solid at room temp)
Melt solid components and allow to mix/dissolve
To identify must know types of metal/solid used.

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Subscript

Say how many atoms of a certain element are present
If there are no subscripts then there is only 1 atom of that element.

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Coefficient

Determines how many is needed
_ c2h4 + 3 o2 –> 2co2 + 2h20

c = 2
h = 4
0 = 6

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Law of conservation of matter/mass

Matter cannot be created or destroyed
During chemical reactions, no matter is lost/gained
Elements you start with, you end with

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Physical changes

Type of matter that has not changed
* mas, shape, volume, state of matter
Change is often reversible
*phase change, shape

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Chemical changes

Type of matter that has changed into another matter
Change is often not reversible
* combustion
Generally, if the observalbe intensive properties have changed, then a chemical change has occured.

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Reactants

Chemicals you start with
* CH4 + 02 —->
[________]
Reactants

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Synthesis equation

A+B ——> AB

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Decomposition equation

AB —–> A + B

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Single replacement equation

AB + C ——> BC + A

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Double replacement equation

AB + CD —–> AD + CB

Combustion equation

C x Hy + o2 —-> CO2 + H2O

Synthesis identification

Count reactants and products, start with 2, end with 1

Decomposition identification

Count reactants and products, start with 1, end with 2

Single replacement identification

You will have a pure element on BOTH sides of the equation

Double replacement identification

Second element of each compound swap

Combustion identification

A hydrocarbon oxygen gas are always the reactants because h2O is always a product

Know how they drew the atom Jj thompson

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Know how they drew the atom Erwin shrodinger

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Know how they drew the atomLouis Debrogile

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Know how they drew the atom Bohr

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Know how they drew the atom John Dalton

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know how the drew the atom Democritus

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Robert milikan

Oil drop * discovered mass/ change of electron *change: 159 ^ 10-19 *Mass: 9.13 ^10-31 kg

Cathode tube ray experiment discovery

An electron is a subatomic particle that is found in all atoms, is negatively charged, and has extremely small mass (200 * lighter than a hydrogen atom).

Alpha particles

2 protons, 2 nuetrons Mass number: 4 amu Charge: +2

Beta particles

Electrons Mass number: 0 Charge: -1

Gamma radiation

High energy proton with short wavelengths Mass number: 0 Charge: 0

Alpha decay

233 -4 229 4 NP ---------> PA + He 93 -2 91 2

Beta decay

40 0 40 0 K -----> Ca e- 19 +1 20 -1

Valence electrons

-Found in the highest energy level of an atom - Responsible for bonding properties of an atom

Rule 1 for lewis dot structure

Write element symbol

Rule 2 for lewis dot structure

Figure out how many valence electrons you need

Rule 3 for lewis dot structure

Draw dots to represent electrons along the symbol Draw on "4 sides", order does not matter Every side needs 1 electron before pairs

Wavelength

Distance between 2 adjacent crests or troughs

Frequency

Number of waves that pass through a given point per second

Photoelcetric effect

WHen a metallic surface is exposed to radiation of a certain frequency, electrons can be emitted

Electron configuration

Shows an arrangement of electrons in an atoms and shows how electrons are distributed in orbital

Lavoisier

Made first list of 33 elements

J.W. Dobereiner

Arranged known elements into triads

John newlands

Arranged by increasing atomic mass

Mendeleev and Lothar meyer

- Ordered 63 elements by increasing atomic mass - Left space for unknown elements

Moseley

Organized by atomic number instead of mass