Transcript File - King`s General Science

Element: A substance containing just one
kind of atom eg Mg, Fe, H2
H2 gas
Ar gas
Compound: is made up of two or more different
elements, chemically bonded together. Has
different properties to the elements that made
them up.
eg CO2, H2O,
H2SO4,
C2H5OH
Molecule: A pair or group of atoms bonded together
eg H2, CO2
CO2 gas
Mixtures
• consists of two or more different elements
and/or compounds physically intermingled,
• can be separated into its components by
physical means
Eg Ar gas
H2 gas
CO2 gas
Element, Compound, or Mixture?
Rocks
Element, Compound, or Mixture?
Rocks
Element, Compound, or Mixture?
Copper
Element, Compound, or Mixture?
Copper
Element, Compound, or Mixture?
Jelly Beans
Element, Compound, or Mixture?
Jelly Beans
Element, Compound, or Mixture?
Table Sugar
Element, Compound, or Mixture?
Table Sugar
Element, Compound, or Mixture?
Diamond
Element, Compound, or Mixture?
Diamond
Element, Compound, or Mixture?
Tea
Elements combine in fixed amounts.
Use a chemical formula to describe elements
eg
FORMULA and NAME
H2O
Water
CH4
Methane
C12H22O11 sugar
# of ATOMS in the
molecule
H2O is really H2O1
2 H + 1 O = 3 atoms
CH4 is really C1H4
4 H + 1 C = 5 atoms
12C + 22H + 11O = 45
atoms
C12H22O11 sugar
Task 1
Here are two different atoms:
Use them to draw a:
a) Compound
b) Mixture
Difference between Mixtures and Compounds
Mixture
• When iron filings and sulphur are mixed in a watch glass,
you can still see the black specks of iron and the yellow
sulphur powder.
Compound
• When a mixture of iron and sulphur is heated, a black shiny
compound, iron [II] sulphide (FeS) is formed.
Difference between Mixtures and Compounds
Mixture
• When a magnet is
brought near this mixture
of two elements, the iron
filings are pulled away
and stick to the magnet.
Sulphur remains in the
watch glass.
Compound
• When the magnet is
brought near it, the iron
of the iron [II] sulphide
remains unaffected.
Iron and Sulphur Practical
A mixture occurs when you combine matter in a way where the components can be
separated again. A compound results from a chemical reaction between components,
forming a new substance. For example, you can combine iron filings with sulphur to form a
mixture. All it takes is a magnet to separate the iron from the sulphur. On the other hand, if
you heat the iron and sulfur, you form iron sulphide, which is a compound.
Aim: Investigate the properties of a mixture compared to a compound
First form a mixture. Stir some iron filings and sulfur together to form a powder. You
have just taken two elements and combined them to form a mixture. You can
separate the components of the mixture by stirring the powder with a magnet.
Method:
• Place 7g iron filings and 4 g sulphur powder in a crucible.
• Mix thoroughly
• Heat the mixture
• Cool
• Observe the colour and take a magnet near it to see if any
particle is attracted to it.
Results / Observations:
Conclusions: