Properties of Matter Chapter 2

The characteristics of a substance that can be observed without changing the identity of the substance Color, shape, texture, volume and mass In order for characteristics to be physical, the substance cannot change into something different when you observe it. Example: A rubber band being stretched A ball of play-dough being squished Physical Properties Chapter 2.1

Density The amount of matter present in a given volume of a substance Expressed in units of grams per cubic centimeter (g/cm 3 ) Density= Mass ÷ Volume M V D Mass Density Volume Chapter 2.1

 A glass marble has a volume of 5 cm 3 and a mass of 13 g. What is the density of the glass?  A small marble statue has a mass of 2.5 kg and a volume of 1000 cm 3. What is its density?  A larger marble statue has the same density and a mass of 10 kg. What is the volume of the large statue? Density Problems

PHYSICAL CHANGES Changes in the physical properties of the substance, not in the substance itself Example: Tearing a piece of paper Melting an ice cube Chapter 2.1

How substances can form new substances Examples: An old car rusting The Statue of Liberty turning green An egg changes consistency when it is cooked Chemical Properties Chapter 2.1

Chemical CHANGES Changing one substance into another. Cannot be changed back to original form Examples: Burning a piece of paper Baking a cake Chapter 2.1

Physical change vs. chemical change Physical change  If you cut fabric, it is still fabric. Changing the size of the fabric does not change its chemical make- up Chemical change  If you burn a match, the match stick turns to ash and is no longer wood. The fire changed its chemical make-up Chapter 2.1

Production of an odor Example: Egg Rotting Change in temperature Example: Fire burning a log Change in Color Example: Bleach taking color out of clothes Formation of bubbles Example: Alka-Seltzer in water Formation of a solid Example: Egg being boiled Signs of a chemical change Chapter 2.1

Signs of a Chemical Change Production of an odor Example: Egg Rotting and spoiled foo food

Change in temperature Example: Fire burning a log Signs of a Chemical Change

Change in Color Example: Bleach taking color out of clothes Signs of a Chemical Change

Gas Production as evidenced by bubbles Example: Alka-Seltzer in water Signs of a Chemical Change

Formation of a solid-a precipitate Mixing two liquids to form a solid Signs of a Chemical Change

 The most sure sign that a chemical change has occurred is the formation of a new substance. Signs of a Chemical Change

Melting: Changing from a solid to a liquid. Melting Point: The temperature a solid will begin to melt at. Example: Water’s melting point is 0° Celsius Freezing: Changing from a liquid to a solid Freezing Point: The temperature a liquid will begin to freeze at Example: Water’s freezing point is 0° Celsius Changes in the states of matter Chapter 2.2 0° C SolidLiquid FreezingMelting

Evaporation: Changing from a liquid to a gas Sublimation: Changing directly from a solid to a gas (never turns into the liquid state) Boiling: Another form of changing a liquid to a gas Boiling Point: The temperature that a liquid will begin boiling at. Example: The boiling point of water is 100° Celsius Changes in the states of matter Chapter 2.2