2.1What is Matter? I can: -identify heterogeneous and homogeneous matter -recognize the parts of a homogeneous mixture (solute and solvent) -recall that water is often used as a solvent since so many substances will dissolve in water -explain why the amount of a solid solute can dissolve in a solvent (temperature increases since the particles have more kinetic energy to overcome the attractive forces)

Chemistry The scientific study of the composition structure, and properties of matter and the changes matter undergoes. Soap, food, carbonated drinks, books…

Matter You are made of matter Matter is anything that has mass and takes up space. The air you are breathing is matter Can you think of anything that isn’t? Light and sound No mass/no volumn.

Atomselementscompounds Will ash ever decompose? Carbon All substances are built from atoms. Smallest unit of an element that maintains the properties of that element. Element: a substance that cannot be separated or broken down into simpler substances by chemical means. Each element has one-two letter symbol. (Capital letter or Capital followed by lower case.) Carbon=C, Iron=Fe, Copper= Cu, Aluminum= Al Over 110 elements we know (90 found on Earth, 20 made in labs and are unstable.)

Compounds Can you imagine yourself putting something made from a silvery metal and a greenish-yellow, poisonous gas on your food? Table salt is a chemical compound that fits this description. Even though it looks like white crystals and adds flavor to food, its components—sodium and chlorine—are neither white nor salty. Compound: substance made of atoms of two or more different elements that are chemically combined. Compounds have different properties than original elements. Hydrogen, oxygen, and nitrogen are colorless gases. Together they form nylon which is a flexible solid.

Molecules Think of atoms like letter of the alphabet… then think of molecules like words that the letter make. Molecule: a particle consisting of two or more atoms that are bonded together.

Chemical Formulas Combination of chemical symbols and numbers to represent a substance. The subscript represents the # of atoms of each element present. C16H10N2O2 How many hydrogen atoms are present? Numbers placed in front of the chemical formula show the # of molecules. 3C16H10N2O2

Pure substances and mixtures Pure substance= matter with fixed composition Element or compound. Ex: helium, aluminum, water, salt. Mixture: combo of two or more substances that are not chemically combined. Ex: air, grape juice (sugar in water, but is not chemically combined) May still have properties similar to pure substances (liquid, sweet)

Mixtures Flour in water Heterogeneous Mixtures- mixture in which different materials can be easily distinguished. Two or more substances can easily be separated by physical means. Immiscible (oil and water)

Sugar in water (dissolves) Homogeneous Mixture: contain two or more gaseous, liquid, or solid substances blended evenly throughout. Every part has to be the same throughout! If you add ice=Heterogeneous mixture! Carbonated drinks Miscible (gasoline)

Practice A pail of sand and water Air Human blood Banana split hetero Air homo Human blood Banana split Chocolate syrup Sea water

Q 1 A _______ is a type of matter with a fixed composition. A. colloid B. mixture C. substance D. solution

Q 2 How many elements are found on Earth? A. 5 B. 10 C. 30 D. 90

Colloids A colloid (KAH loyd) is a type of mixture with particles that are larger than those in solutions but not heavy enough to settle out. The word colloid comes from the Greek work for “glue.” Ex: milk, paints, fog (liquid water floating)

Detecting Colloids One way to distinguish a colloid from a solution is by its appearance. Fog appears white because its particles are large enough to scatter light. You can tell for certain if a liquid is a colloid by passing a beam of light through it. A light beam cannot be seen as it passes through a solution, but can be seen through a colloid. The scattering of light by colloidal particles is called the Tyndall effect.

Suspensions Suspension: a heterogeneous mixture containing a liquid in which visible particles settle. Ex: Muddy pond water Mud particles in water will fall to bottom and water will clear up.