- Slides: 25
Matter • What is matter? – Anything that has volume (takes up space) and has mass. • So… what is mass? – Amount of matter that something contains • Difference between mass and weight? – Weight is force of gravity on mass
Properties of Matter • Characteristics used to describe something • What are some examples? • Properties may be – Qualitative – Quantitative
Properties • Qualitative – Has to do with qualities – Examples • Quantitative – Has to do with quantities - measurements – Examples:
Models • What do we mean by models? – A representation of something to make it easier to understand, or more manageable. • Examples of models: – Model airplane or car – Others? – Scientific models • May be mathematical or physical (visual) …
Models of Water
Properties • Physical – Characteristics that don’t involve a change in identity. Substance doesn’t change into something else. • Chemical – Characteristics that do involve a change in identity. Can only be seen when substance does change into something else.
Changes • Physical – Substance doesn’t change into something else. – Example: tearing paper • Chemical – Substance does change into something else. – Example: burning paper
Property vs. Change • Property – Like Noun • Change – Like Verb
Classification of Matter
Classification of Matter • Now that we have defined chemical and physical properties of matter, we can use that to help us classify it. • One way chemists classify matter is based on its purity.
Classification of Matter • Pure Substance – Matter that has only 1 set of chemical and physical properties. Example: Pure water always has the exact same chemical and physical properties under the same conditions. If water ever tastes different then it isn’t pure water; it fits into our next category.
Classification of Matter • Mixture – Two or more pure substances mixed together. Each substance in the mixture retains its own set of chemical and physical properties. Even though Example: Copper it may and look Zinc can be different, it mixed is still copper together and zinc. to Each produce metal brass. its own properties retains like melting point.
Classification of Matter • Mixture – Two or more pure substances mixed together. Each substance in the mixture retains its own set of chemical and physical properties. Unlike pure substances, mixtures can always be separated by physical means. How could we separate the copper and zinc back out?
Mixtures • Mixture – Two or more pure substances mixed together. Each substance in the mixture retains its own set of chemical and physical properties. If a sample of sand contains iron and salt, how could you separate them from the other minerals?
Mixtures • Some mixtures are more evenly distributed than others. • Heterogeneous mixture – Uneven distribution of substances. - You can see the different parts. Examples: Sand Granite Wood
Mixtures • Some mixtures are more pure than others. • Heterogeneous mixture – Uneven distribution of substances. - You can see the different parts. Examples: Milk Blood
Mixtures • Homogeneous Mixture – Components are evenly mixed. - Cannot see the parts. Salt water contains salt and water, but are mixed all the way to the atomic level, but it can still be separated by physical means. Seawater distillation plant
Pure Substances • Pure substances can be divided into 2 categories: compounds and elements.
Pure Substances • Elements – Substances made up of only one type of atom. - Cannot be separated by any physical OR chemical process. Examples: Carbon Helium Gold
Pure Substances • Compound – Two or more elements chemically bonded together. Examples: Carbon Dioxide (CO 2) Water (H 2 O) Salt (Na. Cl) Sucrose (C 12 H 22 O 11)
Pure Substances • Compounds have only 1 set of properties. They cannot be separated by any physical process. - Can only be separated by a chemical reaction. Water can be separated into Hydrogen and Oxygen by a process called Electrolysis.
Matter Can be separated physically Pure Substance Mixture Can see the parts Heterogeneous Mixture Most impure Cannot be separated physically Cannot see the parts Homogeneous Mixture Can be separated chemically Compound Cannot be separated Element Most pure