Page 12- Physical Property- A property that can be observed with the senses, without altering or destroying the object
Observed by taste, sight, sound, touch, smell
The substance is not chemically changed to a new substance when you observe a physical property
PHYSICAL PROPERTIES Color
Luster – shiny, dull Odor – describes the smell State of Matter – solid, liquid, gas
aka: Phase of Matter Texture – rough, smooth
Mass – describes how much material is in an objectTool: triple-beam balance
Volume – describes how much space the object takes upTools: ruler or graduated cylinder (water displacement)
Density – describes how much mass is in the objects’ volumeFormula: Density = mass ÷ volume
PHYSICAL PROPERTIES
Buoyancy – describes if the material will float in water Sinks = not buoyantFloats = buoyant Magnetic – if the
material attracts other metalsParamagnetic- attraction to magnets transition metals, rare earth
metals, actinides
Diamagnetic- repulsion to magnets
PHYSICAL PROPERTIES
Task: Determine whether King Hiero's goldsmith was replacing gold with a cheaper metal during the manufacture of a gold wreath crown.
First Idea: Melt the irregularly shaped crown and crush it into a cube shape, calculate the volume, compare to the mass; find density!
Problem: King does not approve—“Solve the problem without damaging the crown!”
Baffl ed, Archimedes took a bath and observed the rise of water—he thought he could calculate the volume of the gold crown by water displacement!
Archimedes Principle An object immersed in a fluid
experiences a buoyant force equal to the weight of the fluid it displaces
Determines the volume of an object with an irregular shape
ARCHIMEDES
Malleable – if the material can be pounded, rolled, or bent into a new shape Ductile – if
the material can be pulled or stretched into a rope or wire
PHYSICAL PROPERTIES
Freezing Point- (phase transition) temperature a substance goes from liquid to solid
Melting Point- (phase transition) temperature a substance goes from solid to liquid; Freezing point = melting point
Boiling Point- (phase transition) temperature a substance goes from liquid to gas
PHYSICAL PROPERTIES- PG 12
Conductivity- ability to transmit heat, electricity, or sound
PHYSICAL PROPERTIES
Solubility- ability to dissolve or be dissolved
Chemical property- one that indicates how a substance reacts with something else
The substance is chemically changed to a new substance when you observe a chemical property
ADD MORE EXAMPLES:oxidation (able to react with oxygen)apple slices to turn brown iron rusts
heat of combustion reactivity with waterpHflammability (able to catch fire)
toxicity (able to be poisonous)
radioactivity (spontaneously emitting energy)
sensitivity to lightcauses newspaper to turn yellow)
When elements are arranged in
order of increasing
atomic number, their physical and chemical
properties show a periodic pattern.
HOMEWORK: PKT 9 PAGE 12 -- ELEMENT INVENTORY: ELEMENTS &
COMPOUNDS USED IN EVERYDAY LIVINGFind examples of at
least 4 different elements and compounds listed in the ingredients list on foods, cleaners, household items, etc.
There are many names which you will not recognize—look for element names within the name of the chemicals—do not just choose “Iron”
Common Name
Chemical NameElement Name
Symbol
Red Powerade
Magnesium chloride
Magnesium Mg
Red Powerade
Magnesium chloride
Chlorine Cl
Red Powerade
Potassium citrate Potassium K
Red Powerade
Calcium chloride Calcium Ca
Red Powerade
Potassium phosphate
Phosphorus P
Experiment with describing physical properties of various elements
Diff erent element at each table
4 minutes per rotation- counterclockwise
Put all objects (elements, magnet, calculator, rulers) back in tray before leaving
Take ALL personal belongings with you to next stationTable available for extra items you don’t want to carry!
Color- not “copper” colored
Classification- use PT
Volume- use ruler cm3
Density = m/vBuoyancy- take
element to water trays in back
Magnetic- do not break magnet in half!
Malleable- do not destroy my elements, if they bend, they are malleable!
PHYSICAL PROPERTIES LAB- PAGE 13
FINISH LAB STATIONS: PAGE 13CONCLUSION QUESTIONS: PAGE 14ACC: CALCULATING % ERROR …FOR
DENSITY…
Element Accepted Value for Density (g/cm3)
Nitrogen 0.001145 g/cm3
Aluminum
2.70 g/cm3
Zinc 7.14 g/cm3
Tin 7.265 g/cm3
Iron 7.87 g/cm3
Nickel 8.90 g/cm3
Copper 8.96 g/cm3
Lead 11.3 g/cm3
|calculated value – accepted value|
accepted value
x 100 = % error
1. What do vinegar, lemons, and green apples have in common?
2. What do soaps, shampoo, and detergents have in common?
1. Vinegar, lemons, and green apples have a sour taste and they are acidic
2. You may have accidentally tasted soapy water, shampoo, or detergents and noted that all of these cleaning agents have a bitter taste and are basic.
BELLWORK: THURSDAY
3/15/12 IT…
Ion– an atom that carries a charge because it has lost or gained an electronAtom with more electrons than protons – the atom becomes more negatively charged
An atom with more protons than electrons – the atom becomes more positively charged
The more electrons an atom gains or loses, the more negative or positive it becomes.
ACIDS & BASES- PAGE 15
Cation- “Paws”itively charged ion; lost electrons
The letter t in cation looks like a positive plus sign +: ca+ion
Ex: Hydrogen (H) can be a cation because it easily loses its one valence electron to become H+
Ex. Element X as a cation: X+
Anion- A Negative ION; gained electronsEx: Chlorine (Cl) can be an anion because it easily gains an electron to become stable as Cl-
Ex. Element X as an anion: X-
A substance which when added to water produces hydrogen ions [H+]The strength of an acid is based on the concentration of H+ ions in the solution. The more H+ the stronger the acid.
Characteristics of Acids:Taste sourReact strongly with metals (Zn + HCl)Strong acids are dangerous and can burn your skin
Examples of Acids:Vinegar Stomach Acid (Hydrochloric Acid- HCl) Citrus Fruits
ACID
A substance which when added to water produces hydroxide ions [OH-]The greater the concentration of Hydroxide ions [OH-] the stronger the base. Ex. NaOH (Sodium Hydroxide-a strong base) in water
Basic solutions are called alkalineCharacteristics of Bases:
Taste bitterFeel slipperyStrong bases are very dangerous and can burn your skin
Examples: lye (Sodium Hydroxide- NaOH)Ammonia
BASE
When acids and bases are combined, a process called neutralization occurs
The acids and bases chemically react to create water (a neutrally charged substance) and a salt
WHAT DO YOU THINK HAPPENS WHEN YOU ADD AN ACID TO A BASE?
+
HCl + NaOH H2O + NaCl
pH Scale- “Potential for Hydrogen” Scale; measures acids and bases 0 = pure acid 7 = neutral substance 14 = pure base
Litmus paper- indicator paper that changes colors to tell whether a substance is an acid or a base Acids - turn the paper a shade of red/orange Bases - turn the paper a shade of blue/green
HOW CAN YOU TELL THE
DIFFERENCE BETWEEN AN ACID
AND A BASE?
Bases are materials with a lesser concentration of H+ ions, and a greater concentration of OH - ions
They are measured from 7.1-14 on the pH scale
ACIDS VS. BASES (PH SCALE)
Acids are materials that have a higher concentration of H+ ions
They are measured from 0-6.9 on the pH scale
PERIODIC TABLE CROSSWORD PUZZLES-
PACKET 9, PAGES 18-19
Finish fi lling in the crossword puzzles at the end of the packet!
Do your best from what you know, and use the periodic table and process of elimination to figure out the rest!
Due when you turn in your PACKET 9 next TUESDAY! (3/20)
1. What is the charge of an electron?
2. If an atom gains an electron, what happens to the charge of that atom?
What is it called? Write Chlorine (Cl)
after gaining an e’3. If an atom loses an
electron, what happens to the charge of that atom?
What is it called? Write Sodium (Na)
after losing an e’4. What would you call a
substance with the same amount of H+ and OH- ions?
1. Negative2. More negative charge-
makes the atom negative Negative Ion = Anion Cl-
3. Lose negative charge- makes the atom positive
Positive Ion = Cation Na+
4. Neutral!
BELLWORK: FRIDAY 3/16/2012
1. Why is it important to keep your goggles and lab apron on at all times?
2. Why is it important to use lots and lots of water if you accidentally spill an acid or a base on your skin/in your eyes?
1. They will protect from any chemicals splashing up into your eyes or on your body.
2. Water is usually neutral (pH 7). Adding lots of water to the acid or base will neutralize any of the corrosive material that has gotten on your skin, and will dilute the strength of the acid or base so that it will not burn or irritate you.
ACIDS & BASES LAB
Goals/Objectives Steps through Lab NOW: Make
Predictions on Data Table
Completing the data collection chart
Conclusion Questions Extension Questions
Work in pairs 14 stations
NaOH and HCl with Mrs. Cole
1 ½ minutes at each station
Stay at your station Take tray with you to
each station Only 1 drop/substance Record pH values of
the substances
Time’s up? Move quickly and quietly to the next station
Stay on chair-less side of table
Change aprons at halfway point
ACIDS AND BASES LAB- PAGE 16
1. Why do you think you were asked to include HCl and NaOH in a test of household products?
2. Lemons and oranges have nearly the same acidity and pH. Why might it be easier to eat an orange than a lemon?
3. What did you notice about the pH of distilled (purified) water vs. tap (sink) water? Why is there a difference?
4. Why do you suppose that most body fluids (i.e. saliva, blood, tears) have a pH that is neutral/almost neutral?
ACIDS AND BASES CONCLUSION QUESTIONS
Take home 1 strip of litmus paper and, paying close attention to the safety warnings on each substance, test the pH of liquid substances in your cupboards and cabinets. Fill in the chart and tape or glue your litmus strips in the appropriate column, when they are dry. Tear the strip into 6 pieces Do tests for 6 items
ACC ONLY: Design an experiment similar to the
one completed in class to determine the pH values for solid household substances, such as: antacid tablets, uncoated aspirin tablets, salt, sugar, dishwashing detergent, etc. Write the procedure for how you would conduct this experiment.
EXTENSION QUESTION- DUE TUESDAY 3/20
Name of Substance
Tested
What is the substance used for?
Results: pHResults:
acid/neutral/ base
Litmus Paper
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