deck_15082648 Flashcards
b n What are physical properties?
a description of how a material behaves and responds to forces and energy.
Metal Physical property
Malleable - Can be hammered into any shapeDuctile - Can be stretchedShiny (when polished)good conductors of heat and electricitystrong
What are chemical properties?
how a substance reacts with other substances.
What happens when silver reacts with oxygen
It turns black
What happens when magnesium is put in chlorine gas?
It will burn
Catalyst
Substance that changes the speed of a reaction without being permanently changed itself.
What are the metals used in car catalytic converters?
Platinum, palladium and rhodium
Rust
Rust is an iron oxide formed when iron reacts with oxygen and water or air moisture.
Corrosion
Is when the surface of a metal reacts with oxygen (an oxidation reaction)
Rusting
The corrosion of iron
what metals are used to make roof panels and windows
Aluminium and titanium as both metals corrode naturally in air forming a surface layer of metal oxide. The oxide layer sticks to the surface and doesn’t affect the strength of the metal and protects it from further corrosion.
How do you prevent rust?
You could use paint or a barrier.
What happens when metals react with water?
hydrogen gas and metal hydroxide
How to test for hydrogen?
To test for hydrogen we can use a squeaky pop test as hydrogen is highly flammable and reacts with oxygen to form water
metals + oxygen?
metal oxide
What makes evidence good
If it is accurate and reliable
Accuracy
This describes how close a measurement is to its real value. Accuracy depends on a number of factors including using correct measuring device, controlling variables and the skill of the experimenter
Reliability
If the results are measured by one experimenter are all very close together, then we say they are repeatable.If others get similar close values we say that data is reproducible.If data is reliable it needs to be repeatable and reproducible with a small range of values and few or no anomalous results.
Top 3 reactive metals
Potassium Sodium Lithium
Middle Top reactive metals
Calcium Magnesium Aluminium Zinc
Middle Lower reactive metals
Iron tin lead
Lower reactive metals
Copper mercury silver gold platinum
What happens when a metal reacts with an acid
effervescence occurs and the metal seems to disappear into the solution. Hydrogen is given off and a salt is formed which seems invisible. This is because salts are colourless and soluble so they stay disaollved into the solution.
Metal + Acid ->
Metal salt + hydrogen
Hydrochloric acids ->Sulfuric acids ->nitric acids ->
Chloride saltsSulphate saltsNitrate salts
How to achieve a dry sample of salt?
Add metal to acid and let reaction take place, filter to remove excess of the metal and then heat it to evaporate the water leaving the salt
What are alloys?
Mixtures of metals are called alloys.
What does solder alloy help in?
lower melting point than lead and is used in pipes
What does duralumin help with?
Lighter and streonger than aluminium and is used in planes and is less malleable.
What does stainless steel help in
Stronger and more resistant to corrosion than iron and is used in utensils.
Why are alloys less malleable and keeps their shape better than pure metals?
Pure metals are arranged in organized layers with the same atom making it easier to change it’s shape while in allows the atoms are different which blocks the structure preventing the layers to not slide as easily.
Non-metal properties
Substances with low melting pointsBrittle (when solid)Not shinyPoor conductors of heatPoor conductors of electricity
What to do when writing equations with hydroxide
the equation will be OH not HO
Oxide layer
protective layer prevents further corrosion of metal
Group one metals produce metal hydroxides in?
1:1 ratios, LiOH
Group two metals produce metal hydroxides in?
1:2 ratios, Mg(OH)2
Group three metals produce metal hydroxides in?
1:3 ratios, Al(OH)3
Group one metals produce metal oxides in?
2:1 ratio, M2O
Group two metals produce metal oxides in?
1:1 ratio, MO
Group three metals produce metal oxides in?
2:3 ratio, M2O3
Independent Variable
What we change
Dependent Variable
What we measure
Acid + Alkali
Salt + Water
What is a word equation?
A word equation is used as a quick, shorthand way of writing a chemical reaction.
What is stainless steel made out of?
melting iron and adding carbon, chromium and nickel
What is solder made out of?
melting lead and adding tin, solder melts at a lower temperature than lead, can be useful for acting like a glue on electrical circuits
Pure metals and alloys boiling and melting points?
Pure metals (pure substances) have fixed melting and boiling points. These can be used to identify substances. Alloys (impure substances) have different melting and boiling points depending on the composition of the alloy.
