# EQUATIONS

Equations for B2 science.

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## Thermal Decomposition

calcium carbonate ---> calcium oxide + carbon dioxide

CaCO                 --->   CaO                 +     CO

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## Copper electrolysis

Anode:  Cu ---> Cu   +  2e

Cathode: Cu   + 2e   ---> Cu

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## Word Equation For Rust

iron + oxygen + water ---> hydrated iron(III) oxide

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## Energy efficiency

TOTAL Energy Input = USEFUL energy output + Waste energy output

Efficiency = USEFULEnergy OUTPUT

x100

TOTAL Energy INPUT

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## The power rating of an appliance

Power (in W) = Voltage (in V) x Current (inA)

Energy supplied = power x time

Cost = number of units x price per unit

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## Symbol Equations

Hydrochloric acid = HCl

Ammonia = NH

Sulfuric acid = H  SO

Nitric acid = HNO

Phosphoric acid = H  PO

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## Eutrophication

1. Fertilisers run off and find it's way to rivers and streams.

2. The level of nitrates and phosphates in the river water increases.

3. Algae living in the river water use the nutrients to multiply rapidly, creating an algal bloom. This blocks off the light to the plants below. Plants can't                       photosynthesise, so they have no food and die.

4. Aerobic bacteria feed on the dead plants and start to multiply. They use the oxygen in the water. Pretty much everything dies.

5. This process is called eutrophication.

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## The Haber Process

N  + 3H             2NH

Industrial conditions:

Pressure = High (200 atmospheres)

Temperature = 450

Catalyst = Iron

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## Power stations

1. Fuel produces steam in the boiler.

2. The moving steam drives the blades of a turbine.

3. This movement is converted into electricity by the generator (electromagnetic induction).

4. This then goes into the national grid.

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## Alpha, Beta and Gamma Rays

Alpha:

-Stopped quickly

-Don't penetrate far into materials

-Can be stopped by paper or skin

Beta:

-Penetrate moderately

-Can be stopped by a thin sheet of metal

Gamma Rays:

-Can be stopped using thick concrete or a few centimetres of led.

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Alpha:

-Used in smoke detectors

Beta:

-Used in tracers, which shows if the body is working properly

-Thickness gauges

Gamma:

-Medical uses, treats cancer

-Used to sterilise instruments

-Airlines

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## Asteroids and Comets

Asteroids:

-Belt between Mars and Jupiter

Meteorites:

-Meteors are rocks that enter the Earth's atmosphere, they burn up

-When they hit the Earth's surface, they are a meteorite

-The dust can block out sunlight, causing climate change.

Comets:

-Orbit sun in elliptical orbits.

-As a comet approches the sun, the ice melts and leaves a tail of gas and debris.

-Balls of rock, dust and ice which orbit the sun in elongated ellipses.

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## Unmanned Probes

-Don't have to carry food, oxygen and water.

-Can withstand lethal conditions.

-Cheaper.

-Can't fix simple problems.

-Can't do maintenance and repairs.

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## The Life Cycle of Stars

1. Clouds of dust and gas.

2. The force of gravity makes it spiral together to form a protostar. Gravitational energy is converted into heat energy, so the temperature rises.

3. When the temperature gets high enough, hydrogen nuclei undergo thermonuclear fusion to form helium nuclei. A star us born. This is now a main sequence star which lasts several billion years.

4. Eventually the hydrogen runs out and the star swells into a red giant.

5. A small-to-medium-sized becomes unstable and ejects is's outer layer of dust and gas as a planetary nebula.

6. This leaves behind a white dwarf which eventually cools down and fades away.

7.HOWEVER big stars form red super giants. They undergo more fusion and expand and contract several times. Eventually, they'll explode in a supernova.

8. This leaves a very dense core called a neutron star. If big enough, this will become a black hole.

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## Three different types of rock

Sedimentary: Limestone.

Metamorphic: Marble.

Igneous: Granite.

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## Construction Materials

Glass is made by melting limestone, sand and soda.

Limestone and clay are heated to make cement.

Extracting rocks can cause environmental damage:

-Quarrying uses up land and destroys habitats.

-Transporting rock can cause noise and damage.

-Disused sites can be dangerous.

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