Sorting “stuff” Classifying matter

What’s the matter? Everything that you can see, touch, taste, or smell is matter. Matter may be hard, soft, cold, wet, dry, sharp, or even invisible! Matter may be organized as solid, liquid and gas

Other than its state, what key difference would you use to classify these into two groups? sugar cake mix water gold coca-cola concrete ?

A different way to organize matter Matter can be further organized into mixtures and pure substances. Aha!

Definitions Matter is anything that has mass and takes up space. example: coin, cat, monkey, gold non-example: energy Pure substances are made up of only one type of matter. They cannot be separated into different substances. example: sugar, water, alcohol. non-example: coffee, salt water Mixtures are made up of different substances. They can be separated into different substances. example: sand, coffee, milk non-example: gold, water, salt

Mechanical (heterogeneous) mixtures are mixtures in which the individual substances can be seen. example: sand, cookie dough, milk. non-example: coffee, salt water Suspensions are mixtures in which droplets of one substance are held in another substance. Undisturbed, its parts will usually separate. example: oil and vinegar dressing, o.j., blood non-example: milk, sand. Colloids are also mixtures in which droplets of one substance are held in another substance except the “drops” are so small the mixture will not usually separate easily. It looks like one substance to the naked eye. example: fog, milk, non-example: tomato juice, salt water.

Solutions (homogeneous mixtures) are mixtures of two or more substances in which the individual substances cannot be seen. Solutions look like pure substance, even under the microscope. example: coffee, vinegar, brass, air. non-example: mercury, alcohol, wood

Review

Pure Substance or Solution? Pg. 21 – Fill out chart Check and Reflect for section 2.1, pg. 23 #1-3

A real problem You are given a black liquid in a test tube. It looks like only one substance. How can you tell if it is a pure substance or a solution? This is a real problem!

We must do a scientific test on the liquid! One such test that we could do is called paper chromatography.

Paper chromatography is a test in which a piece of paper is placed inside the fluid to be tested. If the fluid is a solution (i.e. not pure), the different materials will move up to different levels.

QuickLab You will be given a test tube, 2 markers, and a piece of chromatography paper. Set up the chromatography test as shown. 1 ink spot ~ 1cm from bottom water ~0.5cm from bottom Write a hypothesis: Is your ink a pure substance? Do questions # 8-10 on p. 22

Assignment Check and reflect p.23

Unused

possible questions