“What’s the matter?” “IDK, what’s the matter with you?” Ch 2. Energy & Matter “What’s the matter?” “IDK, what’s the matter with you?”

Energy Energy – capacity to do work or to produce heat. There are many types but they can be classified into 3 types: Radiant Energy (Ex. Sunlight) Potential Energy – stored energy (Ex. Water behind a dam) Electrical Potential Energy - Produced when objects of different charges are separted. Chemical potential Energy (Ex. Fuels, Foods stored energy) Kinectic Energy – energy carried by objects in motion.

Measuring Energy One calorie is the amount of heat needed to raise the temperature of 1 gram of water by 1 Celcius degree (1 cal = 1 g X 1 Co) The Calories you eat is the same but 1000 times more so therefore one calorie with a lowercase c is = 1000 Calories with a capital C. so 1 Cal = 1 kilocalorie The SI unit of energy is the Joule 1 cal = 4.184 J

Practice Problems Suppose you use 135 cal of energy to perform a task. How many joules have you used? The energy of a small tomato is about 17 Cal. Convert this measurement to joules.

Law of Conservation of Energy Energy is neither created nor destroyed It is simply changed from one form of enery to another. Question? If energy is neither created nor destroyed, why do people say “we are running out of energy?”

Temperature Gabriel Fahrenheit made the Fahrenheit thermometer – his scale is like the English measuring system. Anders Celsius’ Celsius scale is more like the metric system. He set the scale at 00C for freezing pure water at sea level. And the scale at 1000C for the boiling point of pure water at sea level. Converting from 0C to 0F Celcius Temp = 5/9 X (Fahrenheit temp – 32) Fahrenheit temp = 1.8 X Celcius temp +32

The Kelvin Temperature Scale The Si Unit to measure temperature is K (for Kelvin) named after William Thomson, Lord Kelvin. The change from one degree to the next is the same as in the Celsius scale. The difference is where the zero is set. The zero point for K is called absolute zero. This is the point where all motion (or kinectic energy) of all particles stop. To convert from K to 0C K =0C + 273 or 0C = K - 273

Matter The “stuff” that things are made of is called matter. Matter is anything that has mass and volume. States of matter Solid – holds its shape and has definite volume. Liquid – Does not hold its shape, but does occupy a definit volume. Gas – has no definite shape or volume. Plasma – The interior of the sun.

Changes in State By heating or cooling a sample of solid, liquid, or gas, any of these can be changed from one to another.

Properties of Matter Physical properties – are characteristics that can be observed without altering the identity of the substance. Ex: Density, color, and melting Chemical Properties – characteristics of a substance that cannot be observed without altering the substance. Ex: flammability Chemical Reactions

Law of Conservation of Matter Matter, like energy is neither created nor destroyed.

Elements, Compounds and Mixtures An Element is something that cannot be separated into simpler substances by a chemical change. When 2 or more elements combine in a chemical reaction they form a compound Both an element and a compound are Pure Substances – they have their own unique chemical and physical properties. A mixture is a blend of 2 or more pure substances Heterogenous Mixture – has visibly different parts Ex. Chocolate Chip Cookies, Granite rocks Homogeneous Mixtures – the mixtures parts looks all the same Ex. Sea water or air