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Matter. Chapter 2 notes. Definitions. Matter- anything that has mass and occupies volume Intensive vs. Extensive Properties Extensive properties depend on the amount. Mass and volume are the ONLY extensive properties you will be expected to know.
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Matter Chapter 2 notes
Definitions • Matter- anything that has mass and occupies volume • Intensive vs. Extensive Properties • Extensive properties depend on the amount. Mass and volume are the ONLY extensive properties you will be expected to know. • Intensive properties include everything else. Longer list to come
Intensive properties • Intensive properties – properties that depend on the TYPE of matter NOT the AMOUNT of matter. • This includes all physical and chemical properties.
Physical properties • Physical property – something that can be observed about a substance WITHOUT changing the substance • Melting/freezing point • Boiling point • Color • Conductivity (can it conduct heat/electricity) • Hardness • Malleability (bendyness)
Physical properties • Physical properties also dictate physical changes. Water, along with most other substances, can exist as a solid (ice), liquid (water), or a gas (steam or vapor). • Physical properties govern what state of matter the substance will assume at a given temperature and pressure
Chemical properties • In addition to physical properties, intensive properties also include chemical properties. • Chemical properties determine the ability of a substance to react with or become a different substance. • Examples to come.
Chemical changes • Examples of chemical changes include: • Burning/exploding • Rotting/fermenting • Rusting/corroding • Decomposing • Chemical changes are expressed in chemical reactions.
Chemical substances • Substances are either compounds or elements. • Compounds are a combination of two or more elements • H2O, CO2 (NH4)2SO4, etc. • Elements contain only one element • Li, Fe, O2, C, C60, O3, S8, P4, etc.
Chemical reactions • Compounds can only be separated into their elements by chemical reactions. • For example water, H2O, can be separated into hydrogen and oxygen using a battery. Chemical reaction 2 H2O(l) 2 H2(g) + O2(g) Physical reaction H2O(l) H2O(g)
Symbols vs. Formulas • A chemical formula is made up of atomic symbols. • H is hydrogen • He is helium • All atomic symbols begin with a CAPITAL letter. Some are followed by lower case, but not all.
Symbols vs. Formulas • A chemical formula is simply a combination of two or more atoms • H2O is a chemical formula • H2 is also a chemical formula even though it doesn’t have two different elements. • The little two means that you have two hydrogens.