The Human Organism and Energy

Write the white, just read the blue

WHAT DO YOU KNOW ABOUT ENERGY?

Energy the ability to do work or produce change

Energy is measured in Joules (J) 1J = energy needed to lift 1Newton (100g) up 1 m Unit most often used = kilojoules (kJ)

Energy transformation = when E changes from one form to another

Energy transfer = E moves from one place to another Heat ALWAYS goes from high  low temperature

e.g. Burn a log of wood = chemical E  radiant E (transformation) & thermal E E in log  to warm your hands (transfer)

Examples of E transfer and transformation: Thermal  radiant Chemical  radiant chemical  mechanical Radiant  chemical lamp, baseboard heater nuclear plant lights up city food in body, fuel in car sun and plants

Forms of Energy

There are 4 main forms of energy 1.Thermal 2.Radiant 3.Chemical 4.Mechanical

Thermal Energy Remember the Particle Theory? –Particles are always in motion –The higher the temperature, the more the particles move, the more E they have

Thermal Energy Definition: motion of particles faster they move, the more heat energy produced

Radiant Energy Definition: electromagnetic waves The shorter the wavelength, the more E it has

Get 1m spring

Chemical Energy Definition: E in chemical bonds that hold atoms together E = released when bonds are broken Stronger bond = more E

Mechanical Energy Definition: Energy from motion Depends on speed, mass, relative position Speed = mechanical E mass = mechanical E Height= mechanical E

Compare:

Homework Workbook: pg

Discussion: Textbook pg. 59 Questions 1- 6 (skip 3)

Thermal Energy Lab #16

Discussion: Textbook pg. 60 Question 7-8

Bill Nye Energy

Physical Changes

Workbook: pg. 27 fill it in as we go through the PPT

physical changes = change appearance, but not composition

1. Phase change is when the state of a substance is changed Does not alter the composition

(Absorbed)

Real Life Phase Changes (don’t write this) Ice cubes melt in your drink Mothballs sublimates to a gas that kills moths Liquid CO 2 in paintball tanks evapourates to propel ball Lava freezes to form igneous rock Water condenses on the mirror after a shower Gold vapour deposits on hardware components of computers

2. Dissolution /dissolving =completely mixing one or more solutes with a solvent to form a solution.

Phenomena explained by the mechanism of dissolution (particle theory) The behaviour of mass and volume before and after dissolution: –E.g. 25 g sugar have a volume of 30ml and 100 g of water a volume of 100ml –When mixed together, what will their mass be? 125g sugar Sugary solution

What will the final volume be of the 30ml of sugar and the 100ml of water? Why is this? sugar Sugary solution

Energy and Dissolution Some solutes= release E as dissolve = temperature rises Other solutes =absorb E as dissolve = temperature decreases

Energy and Dissolution Lab #19

3. Deformation =changing of shape (only) of original material

Types of Deformation 1.elastic deformation= object returns to original shape 2.plastic deformation = object remains deformed

Deformation and Energy Energy is required for deformation.

Examples of deformation: Thermal Chemical Mechanical Radiant Heat melts plastic Acid corrodes a battery Trampoline flexes Microwaves cook an egg

Homework: workbook pg. 28

Discussion: textbook pg. 60 questions 9-11

Chemical Changes

Follow along in workbook, pg. 29

chemical change =changes the nature and characteristic properties of matter.

Law of conservation of mass states: Must end with the same number of atoms as you started Start With 1C 4H 4O End With 1C 4H 4O

A+B AB (Reactants) (Product(s) 2H 2 +O 2 2H 2 O

How to tell if a chemical reaction has occurred: 1.Release of gas (the reaction, not you) 2.Change in heat 3.Generation of light 4.Change of colour 5.Formation of a precipitate (solid forms when two liquids mixed)

Types of Chemical Changes

1. Synthesis reaction Synthesis = Formation of a complex molecule from atoms or simpler molecules

A Synthesis Reaction

Energy and Synthesis Some synthesis = release E (explosion) Other synthesis = need E

2. Decomposition reaction decomposition = transformation of complex molecule to simpler molecules or atoms

A Decomposition Reaction

Energy and Decomposition Some decomposition = release E Other decomposition = need E

3. Oxidation reactions oxidation reaction involving oxygen or a similar substance resulting substance = an OXIDE.

Oxidation reactions Some common oxidation reactions are: –Copper turns black, then green –Iron rusts4Fe + 3O 2 Fe 2 O 3 –Magnesium gives off a bright white light (fireworks) 2Mg + O 2 2MgO –Glucose oxidizes into CO 2 and water in the body

Energy and Oxidation Releases E

4. Precipitation reaction precipitation = formation of a solid when two solutions are mixed Pb (NO 3 )2 + 2KI PbI 2 + 2KNO 3

Energy and Precipitation Very little E is required for these reactions (like they just change dance partners)

Real life Chemical changes (don’t write this) Food decomposes in a compost bin An apple turns brown when it oxidizes Plants use carbon dioxide and hydrogen to synthesize oxygen and sugar Adding rennet to milk to precipitate out the curds (cheese), leaving the whey above

Precipitation Lab #23

Discussion: textbook pg. 61 questions 12-15

Using page 112 in your Toolbox on how to create a Concept Map Using the ALL the words on page 61 to create a concept map for Chapter 2 of your textbook. You can use your notes too. Build a Concept Map

Differences in Body Temperature Read the article on page 62 and answer the questions at the bottom. Remember this article when we discuss body temperature regulation later.

Homework: Workbook pg

Bill Nye – chemical reactions

Study questions Workbook pg