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Learning Intentions:
Learning Intentions:
Atoms, Elements, Ions & Compounds
Explain and draw the structure of the Atom.
state the names and symbols of the first 20 elements
understand that the Periodic Table is made up of elements.
Describe how Ions are formed and the charges on the Ions?
What is compound and name some common compounds?
What is mixture and give examples?
Explain why elements and compounds are pure substances?
Classify substances as pure or mixture with reasons.
Metals & Non Metals
Describe the location of metals and non metals on a simple periodic table
list the names and symbols of selected elements and classify them as metals or nonmetals
List some physical properties of metals
Link the uses of metals to their properties
define what is an alloy
understand that alloys have different/better properties than the elements they are made from
list the names of some alloys and what they are made of?
Acids & Bases
Name some common acids and bases and write their formulae
list some physical properties of acids and base.
Test and describe the changes of acids and base on litmus.
Use the universal indicator to find the acidity of a substance
What is an indicator (eg litmus & universal indicators) and pH
Pure Substances
PURE SUBSTANCES are made up of only one type of ELEMENT or COMPOUND. For example: water, oxygen gas, nitrogen gas, copper wire.
Pure substances can either be an element or a compound.
Elements are substances that are only made up of one type of ATOM.
Compounds are substances that have two or more elements joined together by chemical BONDS.
Elements
Elements
If a solid, liquid, or gas is made up of only one type of atom, we say it is an element. For example, consider a tripod made up of iron.
Compounds
Compounds
If two or more different ELEMENTS have chemically reacted together and BONDED, then they form a COMPOUND. So, compounds are different to elements because they contain different ATOMS. Here are some examples:
Methane (CH4) is 1 carbon and 4 hydrogen atoms chemically bonded together.
Sodium chloride (NaCl) are repeating units of 1 sodium and 1 chlorine atom chemically bonded together.
Glucose (C₆H₁₂O₆) is 6 carbon, 12 hydrogen, and 6 oxygen atoms chemically bonded together.
Carbon dioxide (CO2) is 1 carbon and 2 oxygen atoms chemically bonded together.
The name of a chemical compound tells us about the elements that it is made from. The formula of the compound tells us:
Which elements are in the compound.
The proportions of each element present.
Mixtures
Mixtures
Mixtures
If different elements and/or COMPOUNDS are in the same physical space and not chemically BONDED, then they form a MIXTURE.
Mixtures are substances that contain different types of ELEMENTS or COMPOUNDS that are NOT chemically joined together. For example: sea water, orange juice, gasoline, fireworks, cement, mud.
The big difference between a compound and a mixture is that compounds have ONE type of molecule joined together and is therefore very hard to physically separate. Whereas mixtures have MORE THAN one type of molecule that is not joined, and therefore is very easily separate physically.
There are two types of mixtures:
Heterogeneous mixtures are those that have particles that are distributed non-uniformly. Usually, individual components are easy to see with the naked eye.
Homogeneous mixtures are those that have particles that are distributed uniformly. The individual components are not visible with the naked eye.
Solvent , solution , solute
Solvent , solution , solute
Solutions are made from a solute dissolved in a solvent.
A solvent is a substance (such as water) that can dissolve a solute. The solvent 'pulls apart' the bonds that hold the solute particles together and the solute particles diffuse (spread randomly from an area of high concentration to an area of low concentration) throughout the solvent to create a solution.
The solution is a homogeneous mixture because it is a mixture with evenly spread solvent and solute particles. These particles can be physically separated by evaporation.
When solids mix into a liquid and can no longer be seen, they have dissolved. Often the particles of the solute seemed to have disappeared, but they are all still present. They are now just in very small particles too small to be seen by eye.
When solids mix into a liquid and can no longer be seen, they have dissolved. Often the particles of the solute seemed to have disappeared, but they are all still present. They are now just in very small particles too small to be seen by eye.
Many drinks we purchase are solutions. Most of them are solutions of mainly sugar (solute) and water (solvent) with a small amount of flavoring, coloring, and some minerals mixed in. We do not 'see' the sugar because it is dissolved into the water and becomes too small to see. This means a lot of sugar can be hidden in the liquid and we are unaware of the amount of sugar we take in, even in so-called healthy sports drinks.
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