5 MINUTES TO QUIETLY STUDY FOR YOUR QUIZ

BELLRINGER Convert 250 ml to Hl (hecta liters) using dimensional analysis

AGENDA Bellringer Energy & Matter PowerPoint – Chapter 2

CH. 2 – ENERGY & MATTER I. ENERGY, TEMPERATURE & HEAT

A. ENERGY Energy – the capacity to do work or produce heat. Work is the capacity to move an object over a distance against a force; For example: it moves cars, bakes a cake, keeps ice frozen, lights houses, etc. Two Kinds: Kinetic – energy of motion (waves, molecules, objects) Potential – stored energy or energy of position in the chemical bonds

A. ENERGY Forms of energy: 1.Kinetic energy: Electrical Radiant Thermal Motion Sound 2. Potential energy Chemical Stored mechanical Nuclear Gravitational

A. ENERGY Law of Conservation of Energy: Energy is neither created nor destroyed When we use energy, it doesn’t disappear It can be changed from one form to another: 1).A car burns gasoline, converting the chemical energy into mechanical energy 2). Solar cells change radiant energy into electrical energy

A. US ENERGY CONSUMPTION Renewable Biomass 2.9% Hydropower 2.7% Geothermal 0.3% Wind 0.1% Solar & other 0.1% Nonrenewable Petroleum 38.1% Natural Gas 22.9% Coal 23.2% Nuclear (uranium) 8.1% Propane 1.7%

B. KINETIC MOLECULAR THEORY KMT Particles of matter are always in motion. The kinetic energy (speed) of these particles (atoms) increases as temperature increases.

C. FOUR STATES OF MATTER Solids very low KE - particles vibrate but can’t move around fixed shape fixed volume

C. FOUR STATES OF MATTER Liquids low KE - particles can move around but are still close together variable shape fixed volume

C. FOUR STATES OF MATTER Gases high KE - particles can separate and move throughout container variable shape variable volume

C. FOUR STATES OF MATTER Plasma very high KE - particles collide with enough energy to break into charged particles (+/-) gas-like, variable shape & volume stars, fluorescent light bulbs

D. TEMPERATURE Heat or thermal energy - total random kinetic energy of the particles. Heat flows from a hot object to a cold object. For example: can of soda Temperature – measure of the average random kinetic energy of the particles.

D. TEMPERATURE SI unit of temp: Kelvin (K) The zero point on the Kelvin scale is called absolute zero (the point at which the motion of particles ceases). 0 K = o C ( no degree symbol and no negative numbers on the Kelvin scale because there is no negative motion! )

D. TEMPERATURE Formulas: o C = K – 273 or K = o C + 273

D. TEMPERATURE o F = (9/5) o C + 32 o C = 5/9 ( o F – 32)

E. ENERGY UNITS SI unit of energy: joule (J) 1J = energy needed to lift a medium apple 1m against gravity 1500 J = energy needed to climb an average flight of stairs

E. ENERGY UNITS calorie (cal) : unit of energy 1 cal = amount of heat needed to raise the temperature of 1g of water, 1 o C. Conversion factor: 1 cal = J If it takes 1500 J to climb a set of stairs, calculate how many cal this is.

G. ENERGY UNITS 1 cal does not equal 1 Cal ! Calorie (capital C) is the energy stored in food! 1 Cal = 1000 cal or 1 kcal So 200 Cal (a candy bar) supplies 200,000 cal of energy! How many J is this? Calculate. How many times do you have to go up and down the stairs?!

F. DIMENSIONAL ANALYSIS The “Factor-Label” Method Units, or “labels” are canceled, or “factored” out

F. DIMENSIONAL ANALYSIS 1) Your European hairdresser wants to cut your hair 8.0 cm shorter. How many inches will he be cutting off? (See p. 38 and p. 936) 8.0 cm1 in 2.54 cm = 3.1 in or……another way? cmin

F. DIMENSIONAL ANALYSIS 2). How many milliliters are in 1.00 quart of milk? 1.00 qt 1 L 1.06 qt = 943 mL qtmL 1000 mL 1 L 

H. HEAT Specific heat capacity (c): the amount of heat needed to raise the temperature of 1.0 g of a substance 1 0 C. Water has a high specific heat! J/g 0 C

H. HEAT To calculate the heat (energy) released from a substance: q= m Δ t c Heat released m= mass c= specific heat t = change in temperature