Matter & Materials Flashcards
What is teflon used for?
coating cookware
How do insulating sheets work?
insulating sheets placed under the roof trap warm air inside home during winter
reflect heat during summer
what are pure substances?
Pure substances are made of one type of substance. A single element or a single compound. Has no other substance mixed with it
What is an element?
definition
and 2 examples
An element is the simplest type of pure substance which cannot be broken down by chemical reactions into any simpler types of substances
what is a mixture?
Impure substance that consist of 2/more different substances which are physically mixed together in any proportion
discuss 3 characteristics of a mixture
- keeps physical properties
- separated by physical means
- consists of 2/more pure substances mixed together
Describe the difference between homogenous and heterogeneous
& give examples
Homo:
uniform substance - only see one substance and other substances can’t be seen
• salt in water ; jelly power in water
Hetero:
Non-uniform - the different substances can be seen
• mixed nuts ; sand in water ; water in oil
what is a compound?
A pure substance made up of 2/more different types of elements whose atoms are bonded in a fixed ratio by a chemical reaction
What are the physical means of separation?
- hand sorting
- magnets ( iron filings and sulphur )
- machines ( coal , eggs , sand & gravel )
what are 4 ways substances are made easier to separate?
- boiling point
- melting point
- colour
- density
how can we separate mixtures chemically?
- filtration
- separating funnels
- fractional distillation
- chromatography
- decanting ( pouring densities )
- electrolysis
what is a boiling and condensation point?
boiling point is the temp at which a pure substance boils
and the condensation point is the temp at which vapor ( gas ) condenses to become a liquid again
boiling point of a pure substance is the same temp as it condensation point
solutions consisting more than 1 substance have more than 1 boiling point»_space;» individual constituents of a mixture retain physical & chemical properties
what is chromatography?
- method used to separate & identify coloured constituents of a substance
- separates colours by allowing a solution of the dye to be absorbed and move through the chromatographic paper
- colours move through the paper at differing rates
- red travels faster than blue
PURPOSE:
• find out how many colours are present in a dye and to check for matching dyes
what are some physical properties of metals?
- shiny
- relatively high density
- good electrical conductor
- good conductor of heat
- high melting & boiling point
- few metals have magnetic properties e.g iron, nickel & cobalt
name some chemically reactive metals
- Li
- Na
- K
- Zn
- Ca
- Mg
how do chemically reactive metals react
- release hydrogen when they react with acids
* ignite and burn in oxygen forming basic metal oxides
Name 8 non metals
- H
- He
- C
- N
- O
- F
- Ne
- P
- S
- Cl
- Argon
- Br
- I
- Xeon
- Radon
- Krypton
name the physical properties of non metals
- many are gasses at room temp & atmospheric pressures
- relatively low density & melting points
- non metals at are solids eg Sulphur are brittle and will shatter into pieces when hammered
- Only carbon graphite is a good conductor - others are insulators
- dull
name 1 chemical property of non metals
• oxygen reacts with non metals to form acidic oxides
what is the difference between a metal and metalloids
- metalloids electrical conductivity increases with temp ( conducts better in higher temps )
- metal electrical conductivity decreases with increase in temp ( resistance is higher with higher temps )
name 8 metalloids
- boron
- silicone
- germanium
- arsenic
- selenium
- antimony
- tellurium
- astatine
what is an ingenhousz tank and what does it do
helps to measure the thermal conductivity of materials by comparing how quickly temperature rises
- water tank filled with rods of different types of substances
- rods are same length and diameter
- small drop of molten wax is allowed to solidify at the end of each rod
- hot water is then poured in the tank and the best thermal conductors wax droplet melts first
please check the magnetic properties of metals
thanks
what is a metalloid
- neither metal nor non metal
- have similar physical properties to metals eg shiny and dense
- behave more like non metals in chemical reactions
- better conductors when temp increases
- low temps metalloids are insulators
