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Elements, Compounds, and Mixtures. What is a PURE SUBSTANCE?. Pure substances are made of only one type of particle. What is an ELEMENT?. A substance composed of a single kind of atom. Cannot be broken down into another substance by chemical or physical means. What is an ELEMENT?.
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What is a PURE SUBSTANCE? • Pure substances are made of only one type of particle.
What is an ELEMENT? • A substance composed of a single kind of atom. • Cannot be broken down into another substance by chemical or physical means.
What is an ELEMENT? • Elements are considered pure substances • Pure substances are made of only one type of particle.
What is a COMPOUND? • A substance in which two or more different elements are CHEMICALLY bonded together.
What is a COMPOUND? • Compounds are also PURE SUBSTANCES because they are made of only one type of molecule.
How can you separate a COMPOUND? • To separate the components of a COMPOUND, you would have to use chemical changes (like passing electricity through water to break it into hydrogen and oxygen.)
What is a MIXTURE? • Two or more substances that are mixed together but are NOT chemically bonded.
What is a MIXTURE? • Mixtures are NOT considered pure substances because they are made up of 2 or more types of particles or molecules.
MIXTURES – Heterogeneous vs Homogeneous • HETEROGENEOUS means a mixture that does not have a uniform composition. • EX: a bowl of cereal and milk • HOMOGENEOUS means a mixture in which substances are evenly spread out. • EX: a cup of tea has water molecules, tea, and sugar spread evenly throughout.
What is a SUSPENSION? • A heterogeneous mixture in which particles of a material are spread throughout a liquid or gas but are too large to stay mixed without being shaken or stirred up. • EX: salad dressing
What is a SOLUTION? • A homogeneous mixture in which one substance is dissolved into another substance. • EX: Koolaid (solution of water, koolaid powder and sugar).
What is a COLLOID? • A mixture that falls somewhere between a solution and a suspension. • Particles are spread throughout a liquid or gas (like a suspension) • Particles are too small to settle out quickly. • Colloids look homogeneous but are actually considered heterogeneous. • EX: jello