Lesson 7

Density, Temperature, and Fronts

Air masses - form over different regions of land and ocean; have consistent temperatures and moisture density

Cold Fronts

• More dense because the colder it is the more compact
• Cold air masses overtake warm air masses
• Clouds along with rain form right where the differing fronts meet
• Cold air sinks below the warm air mass because it is more dense

Warm Fronts

• Less dense because warmer means expanding
• Warm air mass overtakes the cold air mass
• Clouds form below the warm air where the cold air mass is
• Rain can occur inside the cold air mass
• Warm air rises above the cold front forcing it down because it is less dense

Practice Problems

1. Hot air rises because the warmer the gas particles are the faster they move and expand so they become less dense. This means the warm air isn't as heavy so it rises.

4. Rainy cloudy and cold

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Lesson 6

Sorry Charlie

Charles' Law

Volume is proportional to the temperature, T, in the Kelvin scale

Formula:

k is the proportional constant that indicates how much the volume of gas changes per degree of Kelvin.

This means that you can find a change in volume that comes with a change in temperature

ex: a balloon contains 300 mL of air at 285 degrees Kelvin so at 300 degrees, what will be the volume? To find this we first need to find the constant k. Using the formula, take the volume 300 divided by temperature 285 to get about 1.05 so k=1.05 mL/K. Next we have to figure out the volume of the ballon at 300 degrees. Now using the formula, multiply the constant 1.05 by the temperature 300 to equal 315. The answer is V=315 mL.

Since we learned that when gas is heated up the particles inside move fast and gain more momentum causing expansion, this results in a change of volume. The volume increases meaning the density decreases, which is why hot air rises.

Practice Problems

2. If you have the proportionality constant k then you can multiply it by the temperature to find the volume.
5. 261 degrees Kelvin

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Lesson 4 & 5

Thermometers & Absolute Zero

There are a few different ways to scale something's temperature. Many thermometers contain a type of liquid like alcohol or mercury.

Differences in temperature cause changes in volume


There are particles that make up substances for example liquids, and these particles are moving around in random but determined paths in the liquid. They move at steady paces bumping off of each other and the container, but the speed of the particles can change causing the changes in volume.

• Gases that are heated expand

- the particles are heated and start moving faster and faster with more energy causing the expansion

• Gases that are cooled contract

- the particles are cooled down and they move slower with less energy in the liquid causing it to contract

Temperature of gas is the measure of the average energy of motion of gas particles.

Making a Scale to Measure Temperature

Find:

• Melting point or melting temperature - point where the substance melts or freezes. At this point a solid could melt or the liquid would freeze

ex: block of ice could melt at waters melting point or liquid water could freeze into a solid block of ice.

• Boiling point or boiling temperature - point where a substance boils or condenses. Boiling allows liquid to evaporate into gas but at the same temperature, gas can condense into liquid.

Degree - increment of temperature corresponding to one unit on a thermometer. The size of the degree depends on the temperature scale

- Fahrenheit or Celsius

Convert using the formula F=9/5(C)+32

Converting to Kelvin - K=C+273 or C=K-273

Absolute Zero - temperature 0 degrees Kelvin(K) where the volume of gas is theoretically zero

Practice Problems

3(on lesson 4). Celsius temperature scale is made around zero being freezing and 100 being boiling so it is easier to remember. Celsius can also be converted to Kelvin.

4(on lesson 5). Fahrenheit- 32degrees and 212degrees Celsius- 0degrees and 100degrees Kelvin- -273.15degrees Celsius and 373.15degrres Celsius

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Lesson 3

Having a Meltdown

Density of Liquids and Solids

The formula to determine the density of an object is D= m/v. That's Density equals Mass divided by Volume. It can also be switched around to find mass as long as you know the density and volume and can help find volume as long as you know density and mass.

 

These three things all have a proportional relationship.

The volume of water in 1 liter of rain is more than in 1 liter of snow because snow is less dense therefore can't fit as much actual water in the same amount of volume as rain.

This carries into every phase. Every time something changes phases i.e. liquid to gas or solid or vice versa, there is a change in density.

Practice Problems

3. Snow is not as dense as ice and so ice contains a greater volume of water.

4. Liquid water will take up more volume than ice because it is not as dense as ice.

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Lesson 2

Raindrops Keep Falling

Measuring Liquids

We measure rainfall by inches because volume is dependent on what container you measure it. Volume increases at a steady and predictable way in relation to the height of the beaker.


Proportional - 2 variables are directly proportional when you can multiply the value of one by a constant to obtain the value of the other.

Proportionality constant - number that relates two variables that are proportional to each other, represented by a lowercase k.

Ex: y=5x - the y and x are proportional to each other because one is being multiplied by the constant k(5).

Graphs of one variable is proportionate to another if the line of the two variables pass through the origin of the graph or point (0,0).

Practice Problems

4. Same volume different height.

5. No because some would overflow because they aren't as big and some like the tub would hold more water.

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Unit 3 Lesson 1

Weather

Weather or Not

Weather - state of the atmosphere in a region over a short period of time. The result of interaction between the Earth, the atmosphere, water, and the sun.

Meteorologists look at all things like cloud cover, winds, temperature, air pressure, precipitation and the patterns and connections between them to predict the weather.

Jet stream - high level winds in the upper atmosphere

Fronts - warm: warm air moving in

cold: cold air moving in

Connections

• Precipitation correlates with low air pressure and all kinds of fronts
• Jet stream currents follow the curves and paths of temperature
• Low air pressure around warm and cold fronts
• Jet stream moves from west to east (in the US)
• Rain where there are clouds but clouds don't mean rain

Practice Problems

1. A planet needs an atmosphere, water and the sun to have weather.

3. A physical change is an alteration in the form of a substance like volume, temperature, shape, size, and pressure.

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Unit 1 Review

This first unit was all about elements on the periodic table. What they are made up of like protons, neutrons, and electrons; how they are arranged both on groups with similar properties and by electron shells; and what they make when they combine and bond in different ways. Every element is different and makes up everything in the universe from the least complex like Hydrogen to the most reactive elements.

3. a) lithium- Li, 3, group 1, 3 protons and electrons

    b) bromine- Br, 35, group 7, 35 protons and electrons

    c) zinc- Zn, 30, transition metals, 30 protons and electrons

    d) sulfur- S, 16, group 6, 16 protons and electrons

    e) barium- Ba, 56, group 2, 56 protons and electrons

    f) carbon- C, 6, group 4, 6 protons and electrons

5. An isotope is an atom of an element with the same number of protons but different numbers of neutrons giving it a different atomic mass. The most common isotope is the one with the closest mass to the average atomic mass of that element.

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Lesson 26

Electron Glue

Bonding

Chemical Bond - an attraction between atoms that holds them together in space

• Different electron locations give different properties to substances

Ionic Bonding - type of chemical bond that is the result of transferring of electrons from one atom to another

IONIC

Properties of ionic substances:

Dissolve in water

Conduct electricity when dissolved

Tend to be brittle solids

Made of metal and nonmetal atoms combined

In ionic bonding, the valence electrons are transferred from one atom to another. Metal atoms transfer their valence electrons to nonmetal atoms.

Covalent Bonding - type of chemical bond where one or more pairs of valence electrons are shared between the atoms

MOLECULAR COVALENT

Properties of molecular covalent substances:

Some dissolve in water, some do not

Do not conduct electricity

Some are liquids or gases

Made entirely of nonmetal atoms

In molecular covalent bonding, the valence electrons are shared between pairs or groups of atoms. This creates small stable units, called molecules, within the substance.

NETWORK COVALENT

Properties of network covalent substances:

Do not dissolve in water

Do not conduct electricity

Extremely hard solids

Made entirely of nonmetal atoms

Network covalent bonding is similar to molecular covalent bonding, but the valence electrons are shared throughout the entire substance.

Metallic Bond - bond between metal atoms where the valence electrons are free to move throughout the substance

METALLIC

Properties of metallic substances:

Do not dissolve in water

Conduct electricity

Bendable, malleable solids

Made entirely of metal atoms

In metallic bonding, the valence electrons are free to move about the substance.

Molecule - a group of atoms covalently bonded together

    Metal Atoms      Nonmetal Atoms      Metal & Nonmetal

|                     |              |                          |

|                     |              |                          |

\/                    \/            \/                         \/

Metallic       Network  Molecular            Ionic

Practice Problems

3. a) metallic
    b) molecular covalent
    c) ionic
8. Copper is used as wire because as a solid it conducts electricity but copper chloride as a solid does not conduct.

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Lesson 25

You Light Up My Life

Classifying Substances

Substances can be grouped into general categories: Solubility- the ability to dissolve, and Conductivity- describes how well a substance transmits electricity

Dissolve - to disperse evenly into another substance

We tested substances' solubility by dropping it into some water and seeing if it dissolved. Then to test conductivity we used a battery connected to wires and a lightbulb to see if putting both ends of the wire to the substance would light up the lightbulb.

Types of Substances

Substances that don't light up the lightbulb

                                 -made up of Carbon, Hydrogen, and Oxygen

                                 -entirely nonmetal atoms

                                 -combination of metals and nonmetals in solid forms

Substances that do light up the lightbulb

                                  -has at least one metal atom

                                  -compound of metals and nonmetals when they are dissolved

                                  -metal solids

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Lesson 24

Shell Game

Electron Configuration

electron configuration - a shorthand notation to keep track of the electrons in an atom

• Atoms of elements are arranged on the periodic table by shell numbers. Period one elements have one she'll and period two elements have two shells and so on. Up until period 4 and up all have only four shells.
• Now each shell of an atom has a certain number of subshells. Shell one is only one shell total. Shell two has two subshells for two total, shell three has three total subshells, and shell four has four total subshells.
• Shells are ordered by the 1st subshells are the s shells, 2nd subshells are the p subshells,3rd subshells are the d subshells, and 4th subshells are the f subshells.

            - s subshells are only able to hold a maximum of 2 electrons. Groups 1 & 2

            - p subshells can hold a maximum of 6 electrons. Groups 3-8

            - d subshells can hold a maximum of 10 electrons. Transition metals

            - f subshells can hold a maximum of 14 electrons. Two rows at the bottom

Ex: magnesium, Mg, is in period three so it has three shells, so its electron configuration is 1s2 because the first s subshell is full and can only have a maximum of two electrons, then 2s2 2p6 because all the second subshells are full and p subshells have a maximum of 6 electrons, then 3s2 and it ends there because magnesium is the second element in period 3.

Ex: phosphorous, P, 1s2 2s2 2p6 3s2 3p3

When writing electron configuration, the order of filling in subshells doesn't always go in numerical order. In the middle of the periodic table are the transition metals, the first row of which is in period 4. However The first row is 3d and in period 5 the row of transition metals is 4d. So, when naming elements after the transition elements the numerical order is messed up.

Ex: Germanium, Ge, 1s2 2s2 2p6 3s2 3p6 4s2 3d10 (3d comes after 4s because it is the first row of transition metals and transition metals can hold a maximum of 10 electrons) 4p2.

An even easier way to write the electron configuration is in Noble Gas Shorthand. This means you take the last noble gas before the element you are writing it for and then the regular configuration after that.

Ex: if you want to write the noble gas shorthand for Strontium, Sr, first find the noble gas that came before it which is Krypton, Kr. Put the noble gas in brackets like this - [Kr]. Then use regular configuration afterwards like this - [Kr] 5s2.

Practice problems
4) n-1 has 1 subshell, n-2 has 2 subshells, n-3 has 3 subshells, n-4 has 4 subshells.

5) 14 total subshells

7) 4p

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Lesson 22

Isn't It Ionic

Polyatomic Ions

Polyatomic ion - an ion composed of a group of atoms with an overall positive or negative charge; most are anions

Polyatomic ion      Name

      OH-1            Hydroxide

     NO3-1            Nitrate

     CO3-2          Carbonate

     SO4-2           Sulfate

    NH4+1        Ammonium

     PO4-3         Phosphate

A good way to realize something is a polyatomic ion is if the name of it ends with -ate. Obviously this isn't true of all of them but for most.

A poly atomic ion still needs electrons to fill its shells and so the poly atomic ion as a group of two elements still needs to combine with another element to become full. This means the zero charge rule still applies.

ex: Nitrate has 1 nitrogen atom and 3 oxygen atoms together. Since nitrogen has 5 valence electrons and oxygen has (6x3) 18, that means that the Oxygen atoms get the 5 electrons from the Nitrogen. 18 + 5 is still only 23 which means that the charge is -1 and Ned's to combine with a metal to gain another electron.

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Lesson 21

Salty Eights

Formulas for ionic compounds

All metals and nonmetals want to combine their valence electrons to have full valence shells. This means they want to be like noble gases which have eight valence electrons.

Metals on group 1 on the periodic table want to combine with nonmetals in group 7 to equal 8 and group 2 combines with group 6 and so on. ex: lithium and fluorine combine to form LiF or lithuim floride with a total of eight valence electrons.

3) a. Yes because Lithium has 1 electron and Chlorine has 7 b. No too may electrons c. No too many electrons d. Yes because both Chlorine atom gets one electron e. yes because all Chlorine atoms get one electron

7) a. Al and Br - AlBr3, aluminum bromide b. Al and S - Al2S3, aluminum sulfur c. Al and As - AlAs, aluminum arsenide d. Na and S - Na2S, sodium sulfide e. Ca and S - CaS, calcium sulfide f. Ga and S - Ga2S3, gallium sulfide

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Lesson 20

Getting Connected

Ionic Compounds

Metal elements combine with the nonmetal element chlorine to form compounds
Ionic compound - an ionic compound is a compound composed of positive & negative ions, formed when metal and nonmetal atoms combine
Rule for naming -         (+)           (-) 
                                   Metal    Nonmetal - ide
Li+1S2-                     Lithium    Sulfur - ide
Na+12O2-              Sodium   Oxygen - ide

Rule of zero charge - in ionic compounds, positive charges in cations and negative in anions sum to 0.

Practice Problems
3) Lithium nitride has the formula Li3N.
a. +1 but the three ions add up to +3
b. -3
c. Since the three lithium ions combine have a positive charge of three, when you add them to the nitrogen's negative charge of three it equals 0. (+3) + (-3) =0
d. each lithium atom has 0 valence electrons and the nitrogen atoms has 8 so it is full.

5) a. KBr - (+1) + (-1) =0 b. CaO - (+2) + (-2) =0 c. Li2O - 2(+1) + (-2)

d. CaCl2 - (+2) + 2(-1) =0 e. AlCl3 - (+3) + 3(-1) =0

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Lessons 18, 19

Life on the Edge

Valence and Core Electrons

Electron Shells - levels around nucleus where electrons can be found Atomic # - number of electrons

Period # - number of shells ex: period 1 has one shell, period two has to shells, etc...

Group # - number of valence electrons; this gives element in the same group some similarities

Valence Shell - outermost shell of atom

Valence electrons - electrons in the valence shell

Core electrons - all electrons not in valence shell

Noble Gas Envy

Ions

Ion - atom or group of atoms with a positive or negative charge because it lost or gained electrons

Metal atoms transfer electrons to nonmetal atoms when they form compounds.

• When the metal and nonmetal atoms combine they want to fill their valence shells to become like noble gases that have 8 in their valence shells
• They need to be balanced when they combine. This means that the total number of valence electrons of the two elements need to be a multiple of eight.

Ideally you want compound like elements from group 2 that have 2 valence electrons combining with an element from group 6 which have 6 valence electrons so their total valence electron count is 8. Or from group 1 combining with group 7. These all make it easier.

A lot of the time though The combinations can be with group 1 and group 6 which together only equal 7. However, if you add one more of the same element from group 1 that gives you 1 valence electron from each equalling 2 to add with the group 6 element, giving you 8 total.

For example: say you want to find the chemical equation for combining sodium, Na and oxygen, O. Sodium is in group 1 with one valence electron and oxygen is in group 6 with 6 valence electrons. By adding one more sodium atom it gives you 2 electrons to give to the oxygen atom to fill its she'll, giving you Na2O.

Cation - positive charge (metal)

Anion - negative charge (nonmetal)

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Lesson 17

Flame Test

In class we did a flame test where we held a metal rod dipped in different solution over a flame to observe what colors appeared.

• A flame test is a test used in laboratory to look for the presence of certain metal atoms
• The metal element in each chemical formula appears to be responsible for the flame's colors
• Only certain elements produce colorful flames

The colors in the flames are caused by excited electrons

• Electrons move away from the nucleus
• When they move back they release light energy

        Red                     Yellow-orange            Blue-green                    Pink-lilac
   Lithium, Li               Sodium, Na            Copper, Cu                    Potassium, K
Lithium chloride        Sodium chloride          Copper chloride           Potassium chloride
        LiCl                             NaCl                           CuCl2                              KCl

 Practice Problems

1) How did the flame test provide evidence that specific atoms are present in compounds? The colored flames each had recurring elements.
6) What evidence do you have from flame tests that copper is responsible for producing a flame with a blue-green color? Each blue-green flame had copper in its compound.
10) If two chemical samples both produce an orange flame upon testing, which statement is true? C- the samples both contain calcium atoms

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Lesson 16

Old Gold

Formation of Elements

Nuclear reactions change the identity of an element

Nuclear Fusion

• joins nuclei together changing the identity of the element
• smaller, lighter elements to a bigger, heavier element
• happens in stars

Nuclear Fission

• spontaneous reaction in unstable nuclei
• releases enormous amounts of energy
• nuclear chain reaction as a result

Sample Problems

2) what is a nuclear chain reaction? A nuclear chain reaction is when a neutron emitted by nuclear fission hits surrounding nuclei causing them to split too.

3) Write the nuclear equation for the beta decay of cerium-141.

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Lessons 13 & 15

Subatomic Heavyweights

Isotopes

Isotopes - atoms of the same element that have the same number of protons and electrons but different numbers of neutrons

Isotopes associate with the atomic number and the mass number of an element

• The difference in neutrons but not protons in an atom of an element means that the element doesn't change into another element and the atomic number stays the same while the atomic mass number changes
• Isotopes are referred to by their atomic mass number
• The average atomic mass number of an element on the periodic table is the weighted average of all the naturally occurring isotopes

- the isotope with the mass closest to the average atomic mass is the most common isotope
How do you write an isotope?

Hyphenotation: symbol - mass #

Nuclear notation: mass # with the symbol to the right . atomic #

Practice Problems

4) How many protons, neutrons, and electrons are in each?

a. Fluorine-23: 9,14,9     b. 59                          c. Molybdenum-96: 42,54,42 
                                      27 Co: 27,32,27 

5) An isotope of iron, Fe, has 26 protons and 32 neutrons.

1. What is the approximate mass of this isotope? - 58 amu
2. How would you write the symbol for this isotope? Fe-58

Nuclear Quest

Nuclear Reactions

Nuclear Reaction - a process that involves changes to the nucleus of an atom

Radioactive Decay - a spontaneous process by which an atom emits radiation or a particle from its nucleus to become more stable

• Changes in the nucleus of an atom can change the identity of an element

Alpha Decay

Alpha Decay - emits an alpha particle, atomic # decreases by 2 and mass # decreases by 4

Alpha particle - a particle composed of two protons and two neutrons, or the nucleus of a helium atom

Beta Decay

Beta Decay - neutron changes into proton and electron and atomic number increases by one

Beta particles - an electron emitted from the nucleus of an atom during beta decay

Since during beta decay an electron from the original element leaves, that means the atomic mass goes down by one. However, that neutron then changes into a proton and electron. Therefore, the atomic mass goes back up by one because of the proton and the new proton also cause the atomic number to go up by one making it a whole new element.

Gamma ray - a form of high-energy electromagnetic radiation emitted during nuclear reactions

Practice problems
4) Explain why the mass of an atom changes when an alpha particle is emitted. When an atom emits an alpha particle it is getting rid of 2 protons and 2 neutrons and since protons and neutrons make up an atom's mass, the resulting atom has a mass of 4 less.

6) An alpha particle is not a neutral atom. It has a charge of +2. Why is this? An alpha particle is basically a helium nucleus thus doesn't have electrons meaning the 2 protons make the particle positively charged.

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Lesson 12

Atoms by Numbers

Atomic Number and Atomic Mass

Atomic Number - the number of protons in an atom of an element; elements on the periodic table are arranged in order by atomic number

A neutral atom is one where the number of electrons and protons are equal, therefore balanced.

• The mass of an atom is made up of the protons and the neutrons
• Changing the number of protons in an atom Changes the identity of the element

Practice Problems

3) If you have a sample of atoms and each atom has 12 protons in its nucleus, which element do you have? Magnesium, Mg.
5) Why does carbon, C, gave a larger atomic mass than boron,B, even though they both have 6 neutrons? Carbon has a larger atomic mass because even though the neutron numbers are the same, it has more protons than boron.

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Lessons 6,9, and 10

Lesson 6 - A New Language

Chemical Names and Symbols

All matter in the universe is and element or a combination of elements.

Element - a unique substance that cannot be broken down into simpler substances through any chemical process. ex: Na or Sodium is an element on the periodic table.

Compound - a pure substance that is a chemical combination of two or morelements in a fixed ratio. ex: H2O is water and since H2O is a compound then this means that water is made up of 2 Hydrogen atoms and 1 oxygen atom.

• Compound are represented by chemical formulas. 

Chemical Formula - combination of symbols and subscripts that indicates the number and types of elements in a compound.

• Substances come in different physical forms called phases.

Phase - physical form a substance is in like solid, liquid, or gas.

Aqueous - when a substance is dissolved in water.

Practice Problems
3) How many elements are included in the chemical formula for sodium nitrate, NaNO3? Name them.
Three elements; sodium,Na, nitrogen, N, and 3 oxygen atoms, O3. 
4) What is the difference between NaOH(s) and NaOH(aq)? The s after the compound indicates that it's physical form is solid while aq indicates liquid. 

Lesson 9 - Create a Table

Properties of the Elements

Atomic Mass - the mass of a single atom (or isotope) of an element.

Reactivity - property describing whether an element or compound will chemically combine with other substances as well as the speed of the reaction.

• The periodic table is organized based on the properties of elements with columns of elements on the table share similar properties, reactivity, and atomic mass.

Practices Problems

2) Do you expect carbon,C, to be more similar to nitrogen, N, oxygen, O, or silicon,Si? Why?

Carbon should be more similar to silicon because they are in the same group and elements in the same group share properties. 

5) Suppose you have equal amounts of calcium, Ca, in two beakers. You react the calcium in one beaker with oxygen, O, and the other with sulfur, S. The reaction between calcium and oxygen forms compound CaO. 

1. What do you predict is the chemical formula of the compound formed from the reaction between calcium and sulfur? CaS
2. Which compound has more mass? Explain? The calcium and sulfur compound because their combined mass is 36 not 28. 

Lesson 10 - Breaking the Code

The Periodic Table

Atomic number - the atomic number of an element is the same as the number of protons in the atom of that element. Can be identified as the whole number associated with the element on the periodic table.

Group - a vertical column in the periodic table elements in the group sharing similar properties

Period - Horizontal rows on the periodic table.

Metals - elements that are excelled conductors of heat and electricity, shiny and malleable

Nonmetals - elements that are poor conductors of heat and electricity, dull and brittle, and found to the right of the stair-step line.

Metalloids - elements between the metals and nonmetals,

Practice Problems
5) Which of these elements are solids? B-Titanium,Ti  C-Lead, Pb  E-Poyassium, K  F-Silicon,Si.
6) Which of these elements are nonmetals? A-Bromine, Br  B-Carbon, C  E-Phosphorus, P

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