Formulae and Reaction Quantities S3 Chemistry Unit 2 Topic 2

Naming and Word Equations Learning Intentions: I remember how to name compounds I know what a word equation is I know how to write a word equation Success Criteria: I can name compounds based on the elements it contains. I can write a word equation from a description of the reaction

Glossary Molecule Formed when two or more atoms join together chemically. Compound A molecule that contains at least two different elements (all compounds are molecules but not all molecules are compounds) Gram Formula Mass Mole Concentration

Starter What is the name given to the attractive forces which hold atoms together in molecules? What is the name given when different elements are put together but do not react and join? What is the name given when different elements are mixed and they do react and join? What are the five signs of a chemical reaction? What is the difference between a chemical reaction and a physical change?

Carbon dioxide gas 1) Diatomic element 2) Monatomic element 3)Molecule 4) Diatomic compound 5) Compound 6) Mixture 7) Element Carbon dioxide is a compound and the fire extinguisher would contain millions of carbon dioxide molecules.

Helium gas 1) Diatomic element 2) Monatomic element 3)Molecule compound 5) Compound 6) Mixture 7) Element Helium is an monatomic element because helium atoms do not bond to any other atoms. The balloon is filled with the element helium.

Oxygen gas 1) Diatomic element 2) Monatomic element 3)Molecule compound 5) Compound 6) Mixture 7) Element Oxygen is a diatomic element because it is a molecule made of the same atoms. So we could also say that the canister is filled with the element oxygen.

Sparkling (fizzy) water 1) Diatomic element 2) Monatomic element 3)Molecule 4) Diatomic compound 5) Compound 6) Mixture 7) Element Sparkling water is a mixture of water molecules and carbon dioxide molecules, which are both compounds.

The air around you 1) Diatomic element 2) Monatomic element 3)Molecule 4) Diatomic compound 5) Compound 6) Mixture 7) Element It is a mixture of gas molecules of the diatomic elements nitrogen (N2) and oxygen (O2). It contains the monatomic element argon (Ar) and trace amounts of other noble gas atoms. It will have compounds of carbon dioxide (CO2) and water (H2O) vapour. 

Hydrogen Chloride 1) Diatomic element 2) Monatomic element 3)Molecule 4) Diatomic compound 5) Compound 6) Mixture 7) Element Hydrogen Chloride (HCl) is a diatomic compound but please remember not all compounds are diatomic. For example magnesium chloride MgCl2. hydrogen and chlorine react together to produce hydrogen chloride (HCl ).

Sucrose has the formula C12H22O11 Carbon Snake Dehydration of sugar Demonstration Sucrose has the formula C12H22O11 What will I be left with ?

Carbohydrate Carbon hydrogen (ate) Oxygen

Hydrogen Oxide Hydrogen Oxygen

Naming Compounds ‘-ide’ rule ‘-ate’ and ‘-ite’ rule Compounds made from two elements always end in -ide ‘-ate’ and ‘-ite’ rule Compounds containing three elements, one of which is always oxygen end in -ate or -ite One exception is -OH containing compounds E.g. LiOH is called Lithium Hydroxide

Elements Present Compound Name Sodium, Sulphur, Oxygen Potassium nitrate Calcium, Carbon, Oxygen Magnesium chloride Potassium, Oxygen Sodium, Hydrogen, Oxygen

Word Equations This is a representation of a chemical reaction

Magnesium reacts with oxygen to produce magnesium oxide Magnesium reacts with oxygen to produce magnesium oxide. Reactants: Products: Magnesium Magnesium oxide Oxygen

What to remember 1. We use not ‘=‘ The arrow means ‘reacts to give’

Which is correct? Hydrogen gas is burned in oxygen and water is formed. Hydrogen + Oxygen Water Hydrogen + Oxygen = Water

What to remember 2. Reactants Products

Which is correct? Calcium carbonate reacts with hydrochloric acid producing calcium chloride, water and carbon dioxide Calcium + Hydrochloric Calcium + Water + Carbon carbonate acid chloride dioxide Or Calcium carbonate + Hydrochloric acid Calcium chloride + water + Carbon dioxide

The elements present in the reactants are also present in the products

Write word equations for the following reactions… Carbon monoxide burning to form carbon dioxide. Methane burning to form water and carbon dioxide. Hydrogen sulphide burning to form water and sulphur dioxide. Sodium chloride being produced from sodium and chlorine. When hot lithium is placed in bromine vapour the two elements react to produce lithium bromide. When sodium is heated in a Bunsen flame it bursts into flames, combining with oxygen to form sodium oxide. Hydrogen and chlorine combine explosively in bright light to produce hydrogen chloride. Silicon hydride burns spontaneously in air to produce silicon dioxide and water. Calcium reacts quickly with water to produce calcium hydroxide and hydrogen.