Matter Everything in the universe is made of matter
Mass Weight Quantity of matter an object has Mass never changes unless matter is added or taken away from the object The pull of gravity on mass affects weight Your weight on Earth or your weight on the Moon Matter con’t.
Elements Pure substances that cannot be broken down into simpler substances More than 90% of living things are made of O, N, C, and H Two other very important elements are S and P SPONCH elements
Energy and Matter Energy is ability to do work Forms of energy Light Heat Chemical Electrical Mechanical
Energy and Matter con’t. Energy available to do work is called free energy States of matter Solid—fixed volume and shape Liquid—conforms to container and has fixed volume Gas—fills volume of container and has no fixed volume Plasma
Reduction Oxidation Gains electrons Becomes negatively charged Think chlorine in the ionic bond example Loses electrons Becomes positively charged Think sodium in the ionic bond example Redox Reactions
Acid Base H+ ions Hydronium ions Sour taste Highly corrosive HCl (hydrochloric acid) Citrus juices OH- ions Hydroxide ions Bitter taste Very slippery because they react with oils Soaps Bleach Acids and Bases con’t.
pH A scale that relates numbers of hydronium ions to hydroxide ions Range from 0 to 14 0 acidic 7 neutral 14 basic Logarithmic pH 4 has 10x more hydromium than pH 5 and 100x more than pH 6
Buffers Chemical substances that neutralize acids or bases Extremely important to life Enzymes function in very narrow pH ranges Body fluid pH scale (page 42) Buffer systems maintain the body’s pH at normal and safe levels