Physical & chemical changes

Physical & chemical changes

Time to change and rearrange the changes of change

2 categories of change…

• Physical change: any change that does NOT change the property of matter– Nothing new is made…

• Chemical change: a change where something new is made– Chemical property: how a substances

changes/reacts into something new• yarp

Physical or chemical change???• Ripping paper• Burning paper• freezing water• Frying an egg• Melting iron• Dissolving sugar into water• Reacting acid with metal to make dangerous

gas• Yarp

Tricky reminders…

• Phase changes = physical changes– Solid liquid gas– Ice, water, steam all water

• Dissolving =physical change– Sugar dissolved in water… still sugar and water

• yarp

So much… never too much!!!

• So much we could do an assignment• Yes…• To work…

Matter…

Layers of matter is good

• Element = simplest matter• Atom = smallest unit of an element• Elements are the building blocks of all matter• Over 100 of them. On the periodic table.• We use chemical symbols to represent them.• C = carbon• O = oxygen• Co = cobalt• Yrp = yarp

Woa!!!! Capital letters first, then lower case.

Co = cobalt… CO = carbon monoxide

(carbon and oxygen)

• H = hydrogen He = helium Li = lithium • C = carbon N = nitrogenO = oxygen • F = fluorine Ne = neon Na = sodium • Mg = magnesium Al = aluminum Si =silicon • P = phosphorous S = sulfur Cl = chlorine • K = potassium Ca = calcium Fe = iron • Cu = copper Ag = silver Sn = tin• I = iodine Au = gold Ni = nickel • Hg = mercury Pt = platinum Co = cobalt• Zn = zinc Br = brominePb = lead• As = arsenic U = Uranium Mn= manganese• Ba = barium Fr = francium Yp = yarpium• • You should be able to give me the FULL NAMES or the

CHEMICAL SYMBOLS for these elements!

Expect quizes…

• Yes… practice time on the goodies of elements… sweetness

compounds

Putting elements together

• Compound: 2 or more different elements chemically combined

• Can be broken down into simpler substances• examples– Water = hydrogen and oxygen– Table salt = sodium and chloride– Sugar = carbon, oxygen, and hydrogen– Caffeine = carbon, oxygen, hydrogen, and nitrogen

• Molecule: smallest a compound can get…• yarp

• Chemical formulas = shorthand way of writing compounds

• Rules• 1. write down chemical symbol• 2. give a symbol a subscript in the lower right

hand side for the # of atoms• 3. parenthesis: multiple atoms inside the

(parenthesis) by the subscript on the outside of the parenthesis

• yarp

examples

• 1 carbon, 4 hydrogen

• CO2

• H3PO4

• 3 carbon, 8 hydrogen, 3 oxygen

• Mg(NO3)2

• Elemental molecules = diatomic molecules– 2 atom molecules

• 2 of the same atoms bonded together• How they are found in nature– Nitrogen = N2

– Oxygen = O2 – Fluorine = F2 – Chlorine = Cl2 – Bromine = Br2 – Iodine = I2 – Hydrogen = H2

• yarp

• Finally• Pure substance: a substance made of only

one type of material.– Can NOT be separated by physical means

• Two types– Elements– compounds

• So everything up to this point are pure substances…

• Yarp that

Mixtures….

Putting it together… taking them apart…

• Mixture: 2 or more substances physically mixed together– NOT chemically combined…– Any physical change can separate a mixture.

• In mixtures substances keep their unique properties– Taste, how they react, etc…

• yarp

• Mixtures can be separated physically• Density/let it sit: let more dense things settle• Phase changes.– Boil salt water… water evaporates, salt remains

• Magnetic properties• Filtering– Like coffee

• Chromatography: dissolving separation• Physically separate• yarp

categories of mixtures

• 1. heterogeneous mixture: not evenly mixed– Cereal, skittles– Any salad dressing/juice you mix before using• Because things settled

• 2. homogeneous mixture: evenly mixed– Two types

• A. Colloid: evenly mixed where the mixed particles do NOT dissolve.– The particles do not settle out either… cloudy

usually• yarp

Homogeneous mixtures continued

• Types of colloids• milk = solid and liquid mixed• Gelatin = solid and liquid mixed• Whipped cream = gas and liquid mixed• Smoke = solid and gas mixed• Fog = liquid and gas mixed• Yarp

All done for now!!!!

• Practice time… time to practice..• Sugar lab time… time to use da sugar…• Sweet!!!!!

Solutions…The other type of evenly mixed mixture…

So popular we give it it’s own day

• We learned about before…• A. Colloids…• Now…• B. Solutions: one substance dissolves into

another.– Seems to “disappear”

• Dissolve = the ability to go into solution– Something is physically broken down to the

smallest pieces possible (atoms/molecules)• yarp

Show em how you remember…• Solvent = what things dissolve into• Solute = what gets dissolved into the solvent• Yarp

Identify the solute and solventDealy Solute SolventLemonade

Ocean

14 K gold ring

Human plasma

• Human plasma vs. human whole blood

Dealy Plasma Whole bloodMixture Homogeneous HeterogeneousGet paid??? $$$ DonateHow done Take out and re-

inject blood cells

Keep it all

How used? keep human fluids up

Keep fluids up and give person the cells they need

Types of solutions

Dealy Solute SolventAir Gas (Oxygen) Gas (nitrogen)Carbonated wawa Gas (carbon dioxide) Liquid (wawa)Antifreeze Liquid (ethylene

glycol)Liquid (water)

Ocean Solid (salt) Liquid (wa wa)Jewelry/brass Solid (zinc) Solid (copper)

Water is considered the universal solvent because so many things dissolve into it…

• Soluble = will go into solution/dissolve• Insoluble = will NOT go into solution/dissolve• Solubility = how well things dissolve• What affects solubility????• Yea… what makes things dissolve faster and

slower???• Yarp????

Affect rate/speed of solubility• 1. temperature– ↑ temp = ↑ solubility– ↓ temp = ↓ solubility

• 2. surface area– ↑ surface area = ↑ solubility– ↓ surface area = ↓ solubility

• 3. physical energy (stirring)– ↑ stirring = ↑ solubility– ↓ stirring = ↓ solubility

• yarp

Woa…

• We be done… yet another unit… a woo hoo man!!!

• Hard core review…• Hard core mixtures and pure substances• To the extreme!