Chapter 2: The Human Organism and the Power of Energy

What is energy?• You may sometimes feel like you are having

too much work and not enough energy to do the work!

Energy is the Capacity to do work or to produce change.– Homework induces a change in your brain:

connections between neurons are formed, therefore it requires energy.

100 g

100 gOne Joule represents the energy needed to lift an object weighing one Newton (N) to the height of one meter (m).

1 Joule1 meter

Unit of energy:

The standard unit of energy is the ___________Joule (J) .

On earth 1N = 100 g

100 g

100 g

Calorie

15°C 16°C

Thermal energy• The energy, that is contained in the agitation

of the molecules.

Thermal Energy

Less Thermal Energy

More Thermal Energy

4°C1L

15°C1L

✓

Thermal energy• The energy, that is contained in the agitation

of the molecules.• The amount of thermal energy, that a

substance contains, depends on the degree of agitation of its molecules (temperature)…

• … and on how much substance there is. Which contains more thermal energy?

80°C 50°C

• Melting of snow.

• Lifting of a hot air balloon by heating the air.

Examples of work or change induced by thermal energy.

Radiant energy

• … is the energy contained in and transported by electromagnetic waves

Electromagnetic waves: transport energy from one place to another.• The amount of transported energy depends on

the wavelength and the quantity of radiation. • The shorter the wavelength of a given number

of waves the more energy the wave can transport.

Radiant Energy

Radiant Energy

More EnergyLess Energy

Examples of work or change induced by radiant energy.

• Food is heated by microwaves

• Getting suntanned or burned from ultraviolet rays

Density

• Mass per unit of Volume • Measured in g/mL

Mechanical energy• .. Is the energy that results from the _____of

an object, its _____, and its _____________ _____________.

speedmass relationship to

its surrounding

Mechanical Energy - speed

More

Less

fast

slow

Mechanical Energy - mass

More

Less light

heavy

Mechanical Energy - position

More

Less

Mechanical energy• .. Is the energy that results from the _____of an

object, its _____, and its _____________ _____________.

> The greater the speed the greater the mechanical energy.

> The greater the mass the greater the mechanical energy.

> The higher the object the greater its mechanical energy.

speedmass relationship to

its surrounding

• Crater caused by an asteroid.

• Electricity generated by spinning a turbine (hydro + wind).

• Dent in a car from a crash.

Examples of work or change induced by mechanical energy.

Chemical Energy• … is the energy stored in the bonds of a

molecule• Energy is stored when bonds are formed …• … and can only be released when bonds are

broken and reorganized.

Chemical Energy

GlucosePhotosynthesis

CO2 + H2O

Energy Stored

Chemical Energy

Glucose Respiration

CO2 + H2O

Energy Released

Chemical Energy• … is the energy stored in the bonds of a

molecule• Energy is stored when bonds are formed …• … and can only be released when bonds are

broken and reorganized.• The amount of energy stored in a molecule

depends on the strength and the number of bonds.

• COMBUSTION of gasoline Driving of a car.

• PHOTOSYNTHESIS: light energy chemical energy

• CELLULAR RESPIRATION: chemical energy animals grow move and think.

Examples of work or change associated with chemical energy.

Energy Form Energy Source

Solar Energy Sun

Electrical Energy Power Station

Wind Energy Wind

Sound Energy Sound Waves

Hydraulic Energy Moving Water

Nuclear Energy Nucleus of an atom

Other Forms of Energy

Energy transfer• Energy transfer is the movement of energy

from one place to another:

HEAT is the transfer of thermal energy from one place to another.

• The molecules in the drink transfer thermal energy to the cup the cup gets warm.

• The molecules of the cup transmit vibration energy to the molecules of our skin.

• Agitation of the molecules in our skin feels warm to us.

Heat / Heat transfer

Energy

Transformation of energy

• The transformation of energy is the change of one form of energy into another.

light chemical

chemical chemical mechanicalmechanical

electrical thermal

• Matter• Pure Substance• Compound • Element• Molecule• Particle• Characteristic Chemical

Property• Characteristic Physical

Property

• Mixture• Heterogeneous• Homogeneous• Colloid• Solution• Solute • Solvent• Solubility• Concentration• Dilution

Terms to Know

• Matter is made up of particles that are in constant motion.

• Particles in a solid are very close together and move very little.

• Particles in a liquid are close together and move more than the particles in a solid but less than particles in a gas

• Particles in a gas are very far apart and move a lot.

Particle Model

MIXTURES

heterogeneous homogeneous

Suspension

?✗

ColloidSolution

PURE SUBSTANCES

compounds elements

MATTER

Contain only one type of particle

• Decantation• Centrifugation• Filtration• Evaporation• Distillation• Chromatography

Separation Techniques

• Melting Point• Boiling Point• Density• Solubility

• Do not change the substance during the identification process.

Characteristic physical properties

Chemical characteristic propertiesGas Liqid Certain metal

saltsHydrogenBurning splint test explosion

WaterCobalt chloride paper turns pink

Flame test Flame will take a characteristic colour depending on the metal

OxygenGlowing splint test re-ignition

Acid /BaseLitmus paper acid > red base > blue

Carbon dioxideLimewater test gets cloudy

a) Decantationb) Filtrationc) Centrifugationd) Distillation

Which purification technique would be least useful in separating a mixture of two liquids?

Property Results

Boiling Point 65°C

Mass 79g

Volume 100mL

Colour Clear

Reaction to litmus paper No change

Which of the properties in the table below can help us identify the unknown substance tested?

Identify the Unknown using Apendix 1 in your textbook p.

418-423

a) A bowl of Cereal: ______________________

b) A Toonie: __________________

c) Chocolate Milk: __________________

d) Blood: ___________________

Identify the following as Homogeneous or Heterogeneous

Heterogeneous

Heterogeneous

Homogeneous

Homogeneous