Chemistry

define an element

a substance that consists of only one type of atom

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5 elements and their uses

carbon - used in pencils

oxygen - in breathing equipment

tin - coating in a food can

chlorine - in swimming pool water

mercury - used in some thermometers

properties of metals

• most are solids (except mercury)
• hard and dense
• shiny when freshly cut (lustrous)
• can be hammered into sheets (malleable)
• can be drawn into wires (ductile)
• makes a ‘bell’-like sound when struck (sonorous)
• are good conductors of heat and electricity

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properties of non-metals

• some are solids, some are gases, one is liquid (bromine)
• most are softer than metals (exception is diamonds as they are a form of carbon)
• most are dull
• solids are easily broken when you attempt to change their shape
• not sonorous
• poor conductors of electricity and heat

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where are metals on the periodic table?

all metals are to the left of the staircase

all non-metals are the right of the staircase

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apparatus and chemicals to prepare hydrogen

chemicals

• dilute sulfuric acid
• zinc

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apparatus

• boiling tube
• test tube rack
• lit splint

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test for hydrogen

if you put a lit splint into the gas and it makes a squeaky pop then the gas is hydrogen

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bar charts

• equally spaced out and equal bars#

• title and axis labels (also goo y axis spread)

• title starts with “A bar chart to show…”

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compound

compound - a substance that contains two or more element chemically joined

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molecule

molecule - particle which consists of two or more atoms chemically joined

reaction of iron and sulfur

a red glow spreads through the mixture and a grey/black solid forms (chemical reaction)

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chemical change

• permanent colour change
• fizzing or sign of new gas
• heat or light produced
• solid form in a mixture of two solutions

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physical change

• change in state (solid, liquid, gas)
• can be separated again
• easily reversed

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properties of compounds ≠ properties of elements within

sodium chlorine (common salt) → sodium (very reactive silver metal) + chlorine (poisonous green gas)

water → hydrogen (colourless gas that pops when burned) + oxygen (colourless gas that supports burning)

carbon dioxide → carbon (black solid) + oxygen (colourless gas that supporting burning)

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word equations

non-metal changes ending to ‘ide’

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mixtures

behaves the same way as substances present behave

no chemical reaction

can be made in any proportion

compounds

has new properties

chemical change

made in fixed proportions

when do you use a sieve?

when separating mixtures such as sand and gravel since the sand will pass through but the gravel will not

how to separate sand and salt

• grind mixture

• pour in boiling water

• put the solution through a filter funnel with filter paper

• leave filtrate to evaporate

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chromatography

chromatography - technique for separation of mixture into its components

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why do we need to recycle?

to save finite resources and finite elements

when do you use filtration?

when trying to remove a solid from a solution