Science Notes PDF

**[Science Notes]** **Chapter 6.1** - Matter is split into two different groups: pure substances and mixtures - Pure substance is made from one particle - An example of a pure substance in nature is diamonds - It is hard to find a pure substance in nature - Sugar and aluminum foi...

**[Science Notes]** **Chapter 6.1** - Matter is split into two different groups: pure substances and mixtures - Pure substance is made from one particle - An example of a pure substance in nature is diamonds - It is hard to find a pure substance in nature - Sugar and aluminum foil are human made pure substances - Mixtures contain of two or more pure substances - It can be any combination of solid, liquid or gas - Mixtures don't have the same amount of pure substances - Most mixtures are human made - A few examples are bread and soft drinks **Chapter 6.2** - There are to types of pure substances: elements and compounds - Elements are pure substances that cannot be broken down into another pure substance - There are 118 known elements in the periodic table - Oxygen, iron and aluminum are normal, but some like krypton are rare - Compounds are made from more then on elements - Compounds can be solids, liquids, or gas water hydrogen and oxygen ---------------- -------------------------------------- table salt sodium and chlorine carbon dioxide carbon and oxygen sugar carbon, hydrogen, and oxygen alcohol carbon, hydrogen, and oxygen chalk calcium, carbon, and oxygen baking soda sodium, hydrogen, carbon, and oxygen - Dangerous elements alone are bad for you like chlorine and sodium, but they can become good when they become a compound **Chapter 6.3** - Most substances you use are mixtures - There are four types of mixtures: mechanical, suspensions, emulsion, and solutions - Mechanical mixtures have two or more substances can be seen with unaided eye, one example is granola cereal - Suspension is a cloudy mixture in which clumps of solid and/or liquid are scattered across a liquid or a gas, one example is tomato juice - Emulsion is a special type of suspension which keeps it from separating. The liquid/gas is sprayed through very small openings. This breaks down the clumps into droplets that are so tiny they stay suspended, one example is milk - A solution is a mixture that is so mixed together it looks like a pure substance, one example is apple juice **Chapter 6.4** - There are six ways to separate mixtures: picking apart, filtering, density, magnetism, dissolving, and evaporating - Picking apart is when you simply separate the mixture and sort them into different groups, but it does not work with too small or big you shouldn't use this strategy - Filtering is when you remove a solid from a liquid by passing it through a device that allows the smaller particles through - Density is used if the substances in a mechanical mixture have different densities, one substance may float, and another may settle to the bottom - Magnetism can be used to separate a mechanical mixture if one of the substances in the mixture is attracted to a magnet - Dissolving works if one item is soluble then you can use water to dissolve leaving the other substance behind - Evaporation works if one of the substances are liquid. When the liquid evaporates the other substance is left behind **Chapter 6.6** - A solvent is the liquid that dissolves a soild - A solute is the solid that is dissolved - Concentration is the amount of solute that is dissolved in each quantity of solvent or solution - A solution with a low concentration of solute is said to be dilute - A solution with a higher concentration of solute is said to be more concentrated - A solution is saturated with a solute when no more of the solute can be dissolved in it - A solution is unsaturated with a solute when more of the solute can be dissolved in it. - You can measure the exact amount of solute that is required to form a saturated solution in a certain solvent at a certain temperature - A solution that contains more of the solute than can be found in a saturated solution is called a supersaturated solution **Chapter 6.8** - Acids are compounds that form solutions with the following properties: have a sour taste, react with corrode metals, and can cause serious skin burns - Some examples are lemon juice and vinegar, which are harmless and battery acid - Bases are compounds that form solutions with the following properties: have a bitter taste, feel slippery, react with (break down) fats and oils, can cause serious burns on skin - Some examples are human blood, baking soda, ocean water, milk of magnesia - Litmus paper tells us if the compound is acidic or not - Acidic solutions turn blue litmus paper red but basic solutions turn red litmus paper blue - Scientists measure acidity on the pH scale, a scale of numbers running from 0 to 14 - Acidic have Ph lower than 7.0 and bases are higher than 7.0 - A compound with a pH of 7 (like tap water) is called neutral