Do Now Date: September 19, 2016 Objective: Complete separation of complex mixture and record observations. Read: During the lab: Place separated substances on a paper towel. No solids go in the sink. Smaller quantities of liquids evaporate faster!
Monday, September 19, 2016 Today: Lab: Separating a Mixture Work on Lab Write-Ups Unit Test Friday, Lab Due Friday
During the lab Record your observations! What did the substances look like? Where they pure? Difficulties you experienced. You can collect digital images during the lab (as well as video).
NB Nota Bene Note Well The LAST day to hand in missing labs is this Friday.
Do Now Date: September 20, 2016 Objective: Observe and record data on the Tyndall Effect for solutions, colloids, and suspensions. Copy the table below: Mixture Solution (e.g. salt water) Colloid (water + toothpaste) Suspension (muddy water) Particle Size Small Medium Large Light Tyndall Effect? Notes Passes through Spreads out Spreads out No Yes Yes Doesn t separate Doesn t separate Separates after a while
Tuesday, September 20, 2016 Today: W-Up, Tyndall Effect Demo, Practice Test HW: Google Form (see Breslyn.org) Study for Test on Friday
Tyndall Effect
Solutions, Suspensions, & Colloids Types of mixtures. We can classify them by the size of particle in the mixture.
Tyndall Effect Tyndall Effect colloids and suspensions scatter light in all directions.
Tyndall Effect Image from www.silver-lightning.com/ tyndall/
Tyndall Effect Image from www.silver-lightning.com/ tyndall/
Tyndall Effect Image from www.silver-lightning.com/ tyndall/
Tyndall Effect This effect is also seen when headlights shine into a fog and when sunlight shines through clouds.
Tyndall Effect A short-wavelength wave is stopped or reflected A long-wavelength wave is not affected Image from http://www.madsci.org/posts/archives/nov99/943908453.ch.r.html
Solutions, Suspensions, & Colloids Solutions smallest particles (less than 1 nm). Particles do not settle. Colloids smaller particles (greater than 100 nm) than suspensions (e.g. gelatin desserts, paint). -- Exhibits Tyndall Effect Suspensions mixtures where the particles (1 to 1000 nm) slowly settle (e.g. clay in water). -- Exhibits Tyndall Effect
Elements & Compounds Elements - single atoms for example Fe, Cl, Mg,. Compounds combination of elements H 2 O, NaCl, H 2 SO 4
Elements & Compounds KI HCl Ce U Compound Compound Element Element MnO 2 Compound
Pure Substances Pure substances: have a constant composition cannot be separated or broken down by ordinary physical means. Is water a pure substance?
Mixtures A combination of two or more different substances. Can be separated by physical means.
Mixtures and Compounds What is the difference between a mixture and a compound? Salt Compound (NaCl) Distilled (Pure) Water Compound (H 2 O) Gatorade Salt Water Mixture (H 2 O, electrolytes, sugar, ) Mixture (NaCl and H 2 O)
Homogenous Mixture Same composition throughout. Particles equally distributed. Example: salt dissolved in water. Also called a solution.
Heterogeneous Mixture Varying composition in sample. Example: a salad.
Physical Properties Salt -- Sand -- Paper -- Gravel -- Iron Filings -- Styrofoam --
Wednesday-September 21, 2016 Date: September 19, 2016 Objective: Complete formal write-up of separation of complex mixture and record observations. Read: Follow the rubric! This is how you will be assessed. Each person turns in their own type-written lab. Some part of your lab may be similar but the write-up should be your own work! For the conclusion see Breslyn.org for a possible template.
Thursday-September 22, 2016 Today: Review Practice Test, Study / Alloy Lab HW: Finish Practice Test Work on Final Draft of Separation Lab
Alloys Alloys are a mixture of two or more metals. The mixture has different properties than the individual metals. They could be stonger, conduct electricity better, absorb heat faster,.
Chemical or Physical Change? Chemical changes result in the formation of a new compound.
Evidence of a Chem. Change Changes in heat and light. Color changes. Formation of a precipitate. Formation of a gas (sometimes bubbles). Remember: the change is difficult to reverse.
Warm-Up: Determine the Density Mass of substance: 48 grams Volume of substance: 96 ml What is the density? When placed in water, will it float?
Will it float? A substance was determined to have a mass of 3.2 grams. It s volume was 3.0 ml. When placed in water, will it float?
Do Now Date: September 23, 2016 Objective: complete unit test. Use the time before class to quickly review for the test. Look especially at any information you don t know very well. When you get the test, look it over and try answer questions about this information first. Reminder: Final draft of Separation Lab due next Tuesday!
Friday, September 23, 2016 Today: Unit Test Note: Final typed separation lab is due on Tuesday.
Old Content
Do Now Date: September 18, 2014 Objective: Make an alloy (brass) and describe it s composition. Copy: An alloy is a mixture of two or more metals (and sometimes non-metals). Alloys have useful properties that differ from the original metals. Examples: brass (Zn + Cu), stainless steel (Fe + Cr + Ni)
Thursday, September 24, 2015 Today: Lab: Alloys HW: Study for Unit Test Tomorrow
W-Up
Tyndall Effect
Alloys BCR 1. Use the terms mixture, physical property, physical change, element, atom, heterogeneous, homogenous, and melting point to describe today s lab. 2. How is an alloy different than a compound? 3. We say that an alloy is a mixture of two or more metals. Draw a diagram of how the atoms of zinc and copper would appear if you could see them in a pre-1982 penny and your gold penny.
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Other Periodic Tables http://chemlab.pc.maricopa.edu/periodic/spiraltable.html
Other Periodic Tables http://chemlab.pc.maricopa.edu/periodic/spiraltable.html
Na(s) in H 2 O(l) http://www.theodoregray.com/periodi ctable/stories/011.2/videos/sodiumr esearch02.html
Do Now Date: September 20, 201- Objective: Develop strategy and prepare for unit test Friday. Log in and go to www.breslyn.org. On the paper provided copy and answer: What is your goal for the unit test? What do you need to study most?
What do you need to study? Know what is going to be tested. Focus on areas where you are weak. Study in several sessions.
Today 1. Take the practice test (link on Breslyn.org.) 2. Study the section(s) you did poorly on. 3. Retake the practice test. Show me your score.
Exit Ticket Two topics you still need to study: 1. 2.