520 likes | 539 Views
S2 Chemistry. Introduction to Chemistry. Introduction to Chemistry. 1.1 Reaction Rates 1.2 Chemical Formula (elements) 1.3 Chemical Formula (compounds). 1.1 Reaction Rates. Learning Intentions To learn how to speed up a chemical reaction. Success Criteria.
E N D
S2 Chemistry Introduction to Chemistry
Introduction to Chemistry • 1.1 Reaction Rates • 1.2 Chemical Formula (elements) • 1.3 Chemical Formula (compounds)
1.1 Reaction Rates • Learning Intentions • To learn how to speed up a chemical reaction
Success Criteria • I can list the 4 methods a reaction can be made faster. • I can describe the effect of a catalyst and an enzyme on a reaction • I can do experiments to show how a reaction’s speed can be increased. • I can evaluate and explain graphs showing speeds of reactions. • I can explain everyday reactions and how to speed them up.
Particle Size Apparatus • 0.5M hydrochloric acid • chalk lumps • chalk powder • 2 boiling tubes • test tube rack
Particle Size Method • Two boiling tubes were ¼ filled with 0.5M hydrochloric acid. • 4 lumps of chalk were put into one boiling tube • A similar quantity of chalk powder was put into the other boiling tube • Record your results
Particle Size Results • Decreasing the particle size (making the bits smaller) increases the rate of reaction.
Temperature Apparatus • glucose powder • Benedict’s solution • Metal beaker • Bunsen and bench mat • Tripod and gauze
Temperature Method • Half fill the metal beaker with water. Heat it with a blue flame until it is boiling then switch off the bunsen. • ¼ fill two test tubes with water. Put a spatula of glucose into each test tube. • Put 10 drops of Benedicts into each test tube • Place one of the test tubes into the hot water • Record your results.
Temperature Results • Increasing the temperature increased the rate of the reaction.
Concentration Method
Concentration Results
Summary • To speed up a chemical reaction you could - • Increase temperature • Increase concentration • Decrease particle size
Catalysts • A catalyst is a substance which increases the speed of a chemical reaction without itself being changed.
Enzymes • An enzyme is a biological catalyst
Enzymes • An enzyme is a biological catalyst • Liver contains an enzyme which speeds up certain chemical reactions.
1.2 Chemical Formula (elements) • Learning Intention • We are learning to write element formula
Success Criteria • I can write formula for elements
Chemical Formula (elements) • All elements are given a name and a symbol • eg name hydrogen symbol H
Chemical Formula (elements) • Some elements have symbols that contain two or more letters • eg name magnesium symbol Mg
Chemical Formula (elements) • Some elements have symbols that contain two or more letters • eg name magnesium symbol Mg The first letter only must be a capital letter
1.3 Chemical Formula (compounds) • Leanning Intention • We are learning to write chemical formula
Success Criteria • I can write chemical formula for compounds containing the prefixes mono, di, tri, tetra • I can write chemical formula for compounds with 2 elements • I can write chemical formula for compounds with more than 2 elements • I can write chemical formula for compounds containing roman numerals
Naming Compounds • A compound is formed when 2 or more different elements chemically join together.
Naming Compounds • -ide only two elements forming the compound • -ate two elements plus oxygen • -ite two elements plus oxygen
Valency or Combining Power • The valency or combining power is the number of connections an atom can have with another atom.
Using the Valency • If we know the valencies of the atoms combining then we can work out the formula of the compound they form. • Eg water
Using the Valency • Symbol H O
Using the Valency • Symbol H O • Valency 1 2
Using the Valency • Symbol H O • Valency 1 2 H O
Using the Valency • Symbol H O • Valency 1 2 H O H
Using the Valency • Symbol H O • Valency 1 2 H O H
Using the Valency • Symbol H O • Valency 1 2 H2O H O H No arms can be left unattached
Example – carbon hydride • Symbol C H
Using the Valency • Symbol C H • Valency 4 1
Using the Valency • Symbol C H • Valency 4 1 C H
Using the Valency • Symbol C H • Valency 4 1 H CH4 methane C H H H
Writing Formula • Calcium oxide • Magnesium sulphide • Calcium carbide • Aluminium phosphide • Calcium bromide
Writing Formula • Calcium oxide CaO • Magnesium sulphide MgS • Calcium carbide Ca2C • Aluminium phosphide AlP • Calcium bromide CaBr2
Writing Formula • In certain compounds the name tell you the formula • mono = 1 • di = 2 • tri = 3 • Tetra = 4 Eg nitrogen dioxide = NO2
Writing Formula • Dinitrogen tetraoxide • Hydrogen oxide • Carbon hydride • Nitrogen fluoride • Magnesium carbide • Potassium nitride
Writing Formula • Dinitrogen tetraoxide N2O4 • Hydrogen oxide H2O • Carbon hydride CH4 • Nitrogen fluoride NF3 • Magnesium carbide Mg2C • Potassium nitride K3N
Formula with groups • Groups of atoms can be given a valency as well • Eg the sulphate ion has a valency of 2 SO4
Formula with groups nitrate NO3 phosphate PO4 hydroxide OH
Formula Roman Numerals Roman numerals in a formula give the valency of the transition metal Eg iron (II) oxide
Formula Roman Numerals Roman numerals in a formula give the valency of the transition metal Eg iron (II) oxide O Fe