Chemistry Chemical Reactions Solutions vs. Mixtures
Chemistry is all around us! • Food • Photography • Fisherman • Medicines • Textiles • Playgrounds A CHEMICAL IS ANY SUBSTANCE WITH A DEFINITE COMPOSITION!
What is a Chemical Reaction? • When a chemical reaction occurs, bonds between atoms are formed or broken. • This causes substances to combine and recombine as different molecules. • This happens a lot inside an organism’s cells! • All the chemical reactions that occur within an organism are referred to as that organism’s METABOLISM!
What is a Chemical Reaction? • Scientists use chemical equations to represent the chemical reactions. (Kind of like in math!)
How to Read a Chemical Equation • Plants synthesize complex molecules, like starch, caffeine, and chlorophyll from simple molecules, like CO2 and H2O EX: 6CO2 + 6H2O C6H12O6 + 6O2 Here glucose (sugar) is made from CO2 and H2O!
How to Read a Chemical Equation EX: 6CO2 + 6H2O C6H12O6 + 6O2 ReactantsProducts Yields
Classification of Matter • We can classify matter into one of three states (solid, liquid or gas), but this is very general! • We also classify matter into one of four categories: element, compound, mixture, or solution. Let’s see how to do this!
ELEMENTS • An element is a substance that cannot be broken down into simpler chemical substances. • There are 92 naturally occurring elements on earth and many synthetic elements as well. EX: Gold, Carbon, Lead
COMPOUNDS • A compound is a substance that is composed of atoms of two or more different elements that are chemically combined. EX: Water is a combination of oxygen atoms and hydrogen atoms.
MIXTURES • A mixture is a combination of substances in which individual components retain their individual properties. • So the two substances are not chemically combined! EX: Sand and sugar mixture – you can still pick out the sand particles and the sugar grains. They do NOT make a new substance.
SOLUTIONS • A solution is a mixture in which one or more substances are evenly distributed in another substance. • One substance is dissolved in another! EX: Kool-Aid! The Kool-aid crystals dissolve in water – making a tasty treat!
Use your brain! Matter can be homogenous or heterogeneous! What do those words mean? Remember your roots!
Did you figure it out? If something is HOMOGENOUS, that means it is the SAME throughout! If something is HETEROGENEOUS, that means there are different parts to it!
Chemistry is interesting! Study these notes tonight!