Chemistry 2A

Revision Summary of Chemistry 2A

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What do the mass number and atomic number represent?
The mass number represents the total number of protons and neutrons and the atomic number is the number of protons.
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Draw a table showing the relative masses of the three types of particle in an atom.
proton- mass of 1g neutron- mass of 1g and electron has a very small mass.
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What is a compound?
Compounds are when two or more elements are chemically combined together.
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Define the term isotope.
Isotopes are different atomic forms of the same element, which have the SAME number number of PROTONS but a DIFFERENT number of NEUTRONS.
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Describe process of ionic bonding.
In ionic bonding, atoms lose or gain electrons to form charged particles (called ions) which are then strongly attracted to one another (because of the attraction of opposite charges, + and -). The atoms that perform ionic bonding want a full outer.
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Describe the structure of a crystal of sodium chloride.
The structure is a regular lattice, meaning that the ions are closely packed together. They are very strong as they have strong forces of attraction. It is in a cuboid shape. Na+ and Cl- are held together.
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List the main properties of ionic compounds.
High melting and boiling points due to strong attraction between ions. When ionic compounds melt or are dissolved, the ions seperate and are free to move and will carry electric charge.
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What type of ion do elements in Group 1 and 2 and 6 and 7 form?
Group 1- + Group 2- 2+ Group 6- 2- Group 7- minus
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What is covalent bonding?
Covalent bonding is whn atoms share electrons with each so that they've got full outer shells.
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What are the two types of covalent bonding?
Simple Molecular Substances and Giant Covalent Structures.
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List three properties of metals.
Electrons free to move, so metals are good conductors of heat and electricity. The free electrons also hold the atoms together in a regular structure, there are strong forces of electrostatic attraction between the positive and geative electrons.
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Explain why alloys are harder than pure metals.
Different elements have different sized atoms. So when another metal is mixed with a pure metal, the new metal atoms will distort the layers of metal atoms, making it more difficult for them to slide over each other. So alloys are harder.
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Give an example of a smart material and describe how it behaves.
Nitinol, which is a shape memory alloy. When it's is cool you can bend it and twist it like rubber. If you heat it to a certain temperature, it goes back to its rembered shape. Nitinol is used for dental braces.
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What are nano particles? Give two different applications of nanoparticles.
They are really tiny particles, 1-100 nanometeres across. They have a huge surface area to volume ratio, so they could help make new industrial catalysts. Nano tubes are used to make stronger, lighter building materials.
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Explain the difference between thermosoftening and thermosetting polymers.
Thermosetting polymers dont have cross linking chains. The forces are easy to remove unlike thermosetting polymers. Easy to melt thermosoftening polymers and when it cools it hardens into a new shape wherease the thermosetting doesnt soften when heat
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Define relative atomic mass and relative formula mass.
The relative mass number is usually the same as the mass of the atom, the bigger number is the atomic mass. The relative formula mass is if you have a compound and adding their atomic masses together.
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What is the link between moles and relative formula mass?
The relative formula mass of a substance in grams is known as one mole of that substance.
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Describe three factors that can reduce the percentage yield of a reaction.
Unexpected reactions also happening which use up the reactants.
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Other cards in this set

Card 2

Front

Draw a table showing the relative masses of the three types of particle in an atom.

Back

proton- mass of 1g neutron- mass of 1g and electron has a very small mass.

Card 3

Front

What is a compound?

Back

Preview of the front of card 3

Card 4

Front

Define the term isotope.

Back

Preview of the front of card 4

Card 5

Front

Describe process of ionic bonding.

Back

Preview of the front of card 5
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