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The Particle Theory of Matter. Pure Substances vs. Mixtures. Outcomes. This slide show covers the following course outcomes (refer to your “Outcomes” handout for Unit 3): 3.1 3.2 3.3 3.4 3.5 . Pure Substances & Mixtures. Complete the KWL chart below about pure substances and mixtures.
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The Particle Theory of Matter Pure Substances vs. Mixtures
Outcomes • This slide show covers the following course outcomes (refer to your “Outcomes” handout for Unit 3): • 3.1 • 3.2 • 3.3 • 3.4 • 3.5
Pure Substances & Mixtures • Complete the KWL chart below about pure substances and mixtures.
Pure Substances (p.236) • A pure substanceis matter that is the same throughout. • According to the Particle Theory of Matter (PTM): • All matter is made up of tiny particles. • The particles of one substance differ from the particles of other substances. • What does this mean for pure substances? • We can infer that the particles in a pure substance are identical while the particles in a mixture are different.
Pure Substances (con’t) • To consider pure substances, let’s consider our most important chemical: water. • Most of you should recognize the chemical symbol H2O. What does this mean? • The symbol H2O refers to the parts of a water particle: 2 parts hydrogen (H) to 1 part oxygen (O). • So, if water contains hydrogen and oxygen, why is it considered a pure substance??
Pure Substances (con’t) • The fact that water is a pure substance stems from the definition. That is, it is a substance that is the same throughout. • Q: If you took 10 drops of clear water and looked at each drop under a microscope, what would you notice? • A: Each drop is exactly the same! (Fig.7.5) • Every water particle is identical – each particle contains 2 parts hydrogen and 1 part oxygen.
Mixtures vs. Pure Substances • Now, consider tap water. • Q: How would a drop of tap water compare with a drop of pure water? • A: The drop of tap water would contain water particles (H2O) but would also contain different particles such as chlorine, salt, dirt, etc. • Since there is more than one type of particle, tap water is a mixture (see figure 7.7, p.237)
Summary • A pure substance is matter that is the same throughout. • Every particle in the substance is identical. • Examples: pure water, oxygen, carbon dioxide • A mixture is matter that contains more than one type of particle. • Examples: tap water, air, soup
Review • Read pages 236-237. • Complete the “Reading Check” (#1-3) on page 237. • Complete the “L” column in the KWL chart to explain what you learned and to answer your “wondering” questions. • Research Question: • There are two types of pure substances: elements and compounds. Define these terms and find a few common examples of each.