Science Yearly - All (Flashcards)

Distance

how much ground an object has moved

Displacement

the distance from the start to the end

Displacement is not the

total distance

Displacement and velocity both include

direction

Speed (m/s) =

distance (m) / time (s)

Instantaneous Speed

the speed of an object at a given moment in time

Metres per second to kilometres per hour conversion rate

3.6

Speed is calculated from

distance

Velocity is calculated from

displacement

When an object is moving with a constant velocity, the line on the graph is

horizontal

When an object is moving with an increasing or decreasing velocity, the line on the graph is

vertically sloped and straight

Acceleration (m/s^2) =

(V - U) / Time (s)

V =

Final Speed (m/s)

U =

Initial Speed (m/s)

Final Speed =

Acceleration (m/s^2) x Time (s)

Distance (m) =

Initial Speed (m/s) x Time (s) + 1/2 x Acceleration (m/s^2) x [Time (s)]^2

The more space between dots on a ticket timer

the faster the object is moving

Force is measured in

Newtons (N)

The force of a 100 g object is equal to

1 Newton (N)

Contact forces

applied, frictional (air resistance), tension, normal

Non-contact forces

gravitational, magnetic, electrical

Newton’s first law

an object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force

Newton’s first law is also known as

inertia

Newton’s second law

the size of an object’s acceleration depends directly on the size of the net unbalancing force acting on it and is inversely proportional to its mass.

Newton’s second law formula

force (N) = mass (kg) x acceleration (m/s^2)

Newton’s third law

for every action there is an equal and opposite reaction

Momentum =

mass (kg) x velocity (m/s)

Weight =

force (N)

In the middle of the atom are

protons and neutrons

Nucleus

the central part of the atom that contains both protons and neutrons

Protons and neutrons have a mass of

1

Charge of protons

+1

Charge of neutrons

0

Charge of electrons

-1

Electrons are located

outside of the nucleus

Electrons have a mass of

0.00005

A neutral atom has an equal number of

protons and electrons

The parts of an element square

name, atomic number, symbol and relative atomic mass

The atomic number is equal to the number of

protons or electrons

The relative atomic mass of an atom is compared to

hydrogen

Relative atomic mass =

protons + neutrons

Molecules

atoms joined together

When atoms try to completely fill their outermost electron shell

a molecule is formed

Compound

a molecule with two or more different elements

Valance electrons

electrons in the outermost shell of an atom

Ionic

atoms that bond in metal/non-metal compounds

Ionic bond

the bond between a metal and non-metal

In an ionic bond, the metal

loses an electron

In an ionic bond, the non-metal

gains an electron

Ions are formed through

ionic bonding

Ions

atoms with an electric charge

When a metal loses an electron, it becomes a

ion-cation

When a non-metal gains an electron, it becomes a

ion-anion

When naming an ionic compound

the metal goes first and the non-metal goes last, with an ending of “-ide”

Covalent bond

the bond between two or more non-metals

Covalent bonds form

molecules

In a covalent bond, atoms share

electrons

Evidence for chemical changes

colour change, precipitation, effervescence, energy changes

Effervescence

the release of gases (causes fizzing)

Endothermic

the absorption of energy

Exothermic

the release of energy

Corrosion

the process where metal deteriorates because of the chemical reaction on the surface

Most metals undergo corrosion when

in contact with the air

Rust

the common name for the product of corrosion

Corrosion requires

oxygen, water and an electrolyte

How reactive metals are can be determined by

their position on the periodic table

Ways to prevent corrosion

glazing (zinc), painting/greasing, electroplating

Precipitation reactions involve

mixing two clear solutions and producing a precipitate

Precipitate

an insoluble solid

Precipitation formula

AB + CD → AD + BC

aq

aqueous

Decomposition reactions involve

breaking up a compound into two or more substances through the use of a catalyst or energy

Decomposition formula

AB → A + B

Hofmann Voltmeter

uses electricity to break water molecules into their components; hydrogen and oxygen

Electrolysis

using electricity to split water molecules into hydrogen and oxygen

Alloys

mixtures of metals

Three common alloys

brass, steel, bronze

Alloys are used as they

save costs and help create a material with unique properties

Brass is made of

copper and zinc

Steel is made of

iron and carbon

Bronze is made of

copper and tin or other metals

Electricity

the flow of electrons from one atom to the next.

Metals are good conductors as

they have loosely electrons in their outermost shell, meaning those electrons can flow freely

Electrical energy is the movement of the electrons, NOT

the electrons themselves

Voltage (or potential difference)

a measurement of the amount of “push” forcing the electrons around a circuit.

Voltage is measured with/in

a voltmeter, in volts (v)

Current

a measurement of the rate at which electrons flow through a circuit, or “speed” of flow.

Current is measured with/in

an ammeter, in amperes (I)

Resistance

a measurement of how difficult it is for the electrons to travel through the wire or conductor.

Resistance is calculated from/measured in

voltage and current, in ohms

Ohm’s law: resistance =

current (i) / voltage (v)

Series circuits

circuits where the components are set up in a single path, one after the other

Parallel circuits

circuits with multiple paths for components

A circuit with brighter bulbs

parallel

A circuit with less voltage and current per bulb

series

A simple circuit

series

A complex circuit

parallel

When the circuit is cut, all connections go out

series

Useful for domestic circuits with multiple paths

parallel

The current through each pathway of the circuit adds up to the total current supplied by the source

parallel