TERM 3 MILESTONE

}}%%TESTING, MIXING AND SEPERATING%%}}

]]Compound]]

A compound is any substance that has two or more elements chemically joined together in a fixed ratio.

eg water H2O, salt NaCl, sugar C12H22O11

]]Mixture]]

A mixture is a material made up of two or more substances that are physically combined. Individual substances retain their own properties.

eg air (nitrogen, oxygen, carbon dioxide and other gases), sea water (water, sodium chloride and other salts)

]]But how can we tell the difference between compounds and mixtures?]]

\n ]]Definitions!]]

• A solution is formed when a solute (like sugar) dissolves into a solvent (like water).
• A solvent is a liquid that can dissolve different materials.
• A solute is the substance that dissolves in the solution.
• Dissolving is not a chemical reaction; rather it is a physical process.
• If a substance doesn’t dissolve, it is called insoluble.
• Temperature (or surface area or mixing) can affect how fast something dissolves.

]]Saturated Solution Definition]]

Saturated Solution: a solution where no more solute will dissolve.

If we evaporate a little bit of water from a saturated solution, it becomes supersaturated and crystals start to form

]]Filtration Definition]]

Filtration: separating soluble particles from insoluble particles in a solvent.

]]Mixture of two solids]]

In a mixture of 2 solids, you can:

1. Add water to dissolve one
2. Filter off the insoluble solid (filter paper & filter funnel)
3. Evaporate the water from the dissolved solid - \recrystallise the soluble solute

]]Mixture of Salt and Sand]]

1. Add water - dissolves the salt
2. Filter - sand will collect in the filter paper and filter funnel (residue)
3. Evaporate - heat the salt water until only salt crystals are

]]Magnets]]

• Iron & steel are magnetic.
• Magnets can also be used on mixtures that contain iron or steel to remove these solids.

]]Evaporation Definition]]

1. Separates solute particles from the solvent they have dissolved in.
2. The solution is heated. The solvent forms a gas and evaporates.
3. Solute remains as a solid in the dish.

]]Distillian]]

• If we want to collect the solvent as well, or have 2 different liquids, we use distillation.
• Distillation separates substances based on their boiling points.

]]Chromatography]]

• A way of separating substances into their components based on their solubilities.
• Some inks travel further than others when placed on paper in a solvent

]]Gas Testing]]

$HYDROGEN:$

1. Hydrogen is the first element on the periodic table
2. It’s the most abundant element in the universe

$E.g.$

^^Magnesium + Hydrochloric Acid → Magnesium Chloride + Hydrogen^^

$<strong>You can make hydrogen in the lab by</strong>$:

putting a metal into an acid

$<strong>Observations:</strong>$

Bubbles will form

$<strong>Testing for Hydrogen:</strong>$

trap the bubbles, hold a lighted splint in the gas - makes a squeaky pop sound

$OXYGEN:$

1. Major part of the Earth’s crust
2. Important in combustion and respiration

$E.g.$

^^Manganese Dioxide^^

^^Hydrogen Peroxide ------------------------> Water + Oxygen^^

$<strong>You can make oxygen in the lab by</strong>$ :

You can make oxygen in the lab by putting a pinch of manganese dioxide (black powder) into hydrogen peroxide.

$<strong>Observations:</strong>$

Bubbles will form

$Testing for Oxygen:$

trap the bubbles, hold a lighted splint in the gas - splint should relight (often many times)

$CARBON DIOXIDE$

1. CO2 is essential for life on earth
2. PLants need it for photosynthesis
3. Used in fire extinguishers (does not support combustion)

$E.g.$

^^Calcium Carbonate + Nitric Acid → Calcium Nitrate + Carbon Dioxide + Water^^

$<strong>You can make oxygen in the lab by</strong>$:

adding acid to a metal carbonate solid or solution

$<strong>Observations:</strong>$

Bubbles will form

$Testing for Carbon Dioxide:$

use a delivery tube to bubble this gas through limewater, the limewater should turn milky

}}%%LIGHT AND SOUND%%}}

]]Light Definition]]

1. Light is a type of energy.
2. It is the only form of energy visible to the human eye.
3. Its comes from converting one type of energy into another type of energy.
4. Light travels as a wave.

]]Electromagnetic Spectrum]]

There are many wavelengths of light - we cannot see most of these with our eyes. \n This is called the electromagnetic spectrum

$Radiation Types$

• Radio waves (Radios, TV)
• Microwaves (Cooking, Mobile Phones)
• Infrared (Temperature, thermometers)
• Visable (Projectors)
• Ultraviolet (Solar Power, Solar Panels)
• X-rays (X-rays)
• Gamma rays (Cancer Treatment)

]]Properties of Light]]

• Light travels at 300, 000 km every second
• Light only travels in straight lines - but it can bend and bounce
• Light can travel through empty space
• The basic properties of light are its wavelength, frequency, energy and speed.

]]How do we see light?]]

Light reflects off of objects around us into our eyes.

]]Letting the Light Through]]

• TRANSPARENT: lets all light pass through
• TRANSLUCENT: lets some light pass through
• OPAQUE: blocks light from passing through

]]Law of Reflection]]

Angle of incidence = Angle of reflection

]]Concave Mirrors]]

Concave mirror: shiny surface on the INSIDE of the curve. “Converging Mirror”, light rays come together.

$Features of a Concave Mirror$

The image depends on how far away the object is from the mirror

Within the focal length: magnified, upright & virtual.

$What can they be used for?$

Searchlights, shaving mirrors, dental mirrors, satellite dishes, and more.

$Concave Lens$

• Thin in the middle, thicker at the edges
• We say that the rays are diverging (moving apart from one another)

]]Convex Mirrors]]

Convex mirror: shiny surface on the OUTSIDE of the curve. “Diverging Mirror”, Light rays move away from each other.

$Features of a Convex Mirror$

• Virtual and Upright.

• Smaller than the object .

• Image appears closer & a wider view can be seen.

• The image is behind the convex mirror.

$What can they be used for?$

Magnification glasses, sunglasses, and rear view mirror in vehicles, ATMs, and street lights.

$Convex Lens$

• Thick in the middle, thin at the edges
• We say that the rays are converging (moving closer to another)

]]Internal Reflection]]

• Light is able to enter a diamond but is reflected off multiple times before it can escape.
• This is how they sparkle - through internal reflection.
• When light travels from plastic to air, it bends away from the normal
• At one angle of incidence, the refracted ray will be 90° to the normal.
• This angle of incidence is called the critical angle
• If the angle of incidence is larger than the critical angle, none of the light escapes. \n It is all internally reflected.

]]Fibre Optic Cables]]

Fibre optic cables use total internal reflection to send messages at the speed of light

]]ROYGBIV]]

Red, Orange, Yellow, Green, Blue, Indigo, Violet.

]]Seeing Colours]]

• Objects absorb some light colours and reflect others
• The colours that are reflected are the ones that we see
• Some objects look white because they reflect all of the colours
• Some objects look black because they absorbw all of the colours.

]]Mixing Light Colours]]

1. Red + Blue = Magenta
2. Blue + Green = Cyan
3. Red + Green = Yellow

]]Parts of the Eye - Descriptions]]

• Cornea: clear tissue that covers the front of the eye.
• Pupil: opening through which light enters the eye
• Iris: Coloured part of the eye, controls the amount of light entering the eye
• Lens: focuses light on the retina. Image is upside-down
• Retina: Layer of light sensitive cells in the back of the eye which responds to light. Rods and Cones send electrical impulses to the optic nerve.
• Optic Nerve: Sends signals to the brain

]]Parts of the eye similar to a Camera]]

]]Binocular Vision]]

• Our brain receives signals from both of our eyes at the same time
• The brain can use the two perspectives to judge distances and coordinate our movements in space and time

]]Sound Definition]]

• Sound is a form of kinetic energy
• Sound travels in waves
• Sound waves are produced whenever something vibrates

]]What is a Wave?]]

• A wave transfers energy without transferring matter
• A wave consists of up and down movements called oscillations

$Longitudinal Waves$

Oscillations are along the direction of travel

\n ]]SPEED OF LIGHT AND SOUND - IMPORTANT]]

Speed of light = 300,000,000 m/s

Speed of sound = 330 m/s

]]Why can’t sound travel through space?]]

Sound requires particles to vibrate to transmit energy

]]Differences between sound and light]]

]]Definitions for measuring waves]]

1. Frequency, measured in Herts (Hz) is the number of waves per second. High frequency = high pitch.
2. The amplitude of a sound wave is the distance from the centre (equilibrium) to the top of the peak (or bottom of the trough). Larger amplitude = louder sound. Loudness is measured in decibel.
3. Wavelength is measured from peak to peak & is inversely proportional to frequency. This means that as wavelength increases, frequency decreases.

]]Hearing]]

• Vibrating sound waves are collected by our outer ear
• Sound waves travel to our eardrum, which vibrates
• These vibrations are passed through 3 tiny bones, which causes the fluid in our cochlea to move
• These movements cause the auditory nerve to send signals to our brainE

]]Extra Defintions]]

$<strong>Angle of incidence</strong>$ - The angle between the incident ray and the normal

$<strong>Angle of reflection</strong>$ - The angle between the reflected ray and the normal

$<strong>Angle of refraction</strong>$ - The angle between the refracted ray and the normal

$<strong>Concave</strong>$ - Curved inwards

$<strong>Convex</strong>$ - Curved outward

$<strong>Focal length</strong>$ - The distance between the center of a lens or curved mirror to the focal point of the lens or mirror

$<strong>Focal point</strong>$ - Point where reflected or refracted light rays meet or appear to have met

$<strong>Focus</strong>$ - Bringing light together to make a clear image

$<strong>Image</strong>$ - A picture of an object produced by a lens or mirror

$<strong>Incident ray</strong>$ - Incoming light ray

$<strong>Laterally inverted</strong>$ - Reflected from left to right

$<strong>Normal</strong>$ - Imaginary line at 90° to where a light ray hits a surface

$<strong>Optic nerve</strong>$ - carries electrical impulses from the eye to the brain

$<strong>Absorption</strong>$ - A process by which light is absorbed and converted into energy

$<strong>Lens</strong>$ - Transparent glass or plastic that bends light

$<strong>Virtual (unreal) image</strong>$ - Occurs when light rays don't pass through the point where the image is

$<strong>Total internal reflection</strong>$ - the complete reflection that takes place within a substance when the angle of incidence of light striking the surface boundary is greater than the critical angle

$<strong>Spectrum</strong>$ - All the colours of the rainbow that make up sunlight

$<strong>Reflected ray</strong>$ - Rays of light can be reflected from incident rays striking a surface

$<strong>Refracted ray</strong>$ - Light ray after it has entered a new medium

$<strong>Refraction</strong>$ - Bending of light as it passes through a transparent substance

$<strong>Retina</strong>$ - Black back of the eye where the light is focused onto

$<strong>Real Image</strong>$ - Occurs when light rays pass through the point where the image is

$<strong>Prism</strong>$ - Triangular block used to disperse white light

$<strong>Transmission</strong>$ - Passing of light through a transparent substance

$<strong>Binocular vision</strong>$ - vision with 2 eyes, allowing for perception of depth

$<strong>Echo</strong>$ - a sound or sounds caused by the reflection of sound waves from a surface back to the listener

$<strong>Electromagnetic (EM)</strong>$ - radiation of waves of different wavelengths & frequencies

$<strong>Frequency</strong>$ - number of waves passing a point in a certain amount of time

$<strong>Hertz</strong>$ - SI unit for frequency

$<strong>Law of reflection</strong>$ - the angle of reflection is equal to the angle of incidence

$<strong>Light</strong>$ - electromagnetic radiation that can be seen by the human eye.

$<strong>Medium</strong>$ - substance or material through which something is transmitted

$<strong>Opaque</strong>$ - blocks light from passing through

$<strong>ROYGBIV</strong>$ - Colors of the visible spectrum in order of wavelength and frequency.

$<strong>Translucent</strong>$ - lets some light pass through

$<strong>Transparent</strong>$ - lets all light pass through

$<strong>Vacuum</strong>$ - a space which contains no matter or particles

$<strong>Wavelength</strong>$ - The distance between two corresponding parts of a wave (such as peak to peak)

$<strong>Amplitude</strong>$ - distance from the centre of a wave to the top of the peak

$<strong>Audible</strong>$ - able to be heard