Unit 7 - Reactions of Metals and Their Compounds Chapter 8 in Text Books

Lesson Aims: To understand the differences between CHEMICAL and PHYSICAL reactions. To know the different types of chemical reactions

Chemical and Physical Changes What is the important difference between and CHEMICAL and PHYSICAL change? PHYSICAL = the substance does not become a new substance CHEMICAL = a new substance is created 3 minutes – read p70 and discuss it.

CHEMICAL or PHYSICAL? Draw a table in your books. Choose whether the following are chemical or physical changes, and why.

Types of Chemical Reaction READING RACE…

What are the 4 main types of chemical reaction?

What happens in a combination reaction? (give an example)

What happens in a single displacement reaction? (give an example)

What happens in a decomposition reaction? (give an example)

What happens in a double displacement reaction? (give an example)

Answer race! Using the questions on page 71… GO!!!

CHEMICAL reactions Reagents Observation Evidence for chemical reaction Explanation 1 Add 5mL of copper sulfate(CuSO4) to a small piece of zinc(Zn) in a small beaker or petri dish 2 Collect 5mL of limewater(Ca(OH)2) in a test tube. Gently blow through a straw into the test tube until a change occurs. 3 Strongly heat 5g of copper carbonate(CuCO3) in a test tube. 4 Add 5mL of barium chloride(BaCl2) to 5mL of diluted sulfuric acid(H2SO4) in a test tube. 5 Add 5mL of lead nitrate (Pb(NO3)2) to 5mL of potassium iodide(KI) in a test tube. 6 Add 5mL of sodium carbonate(Na2CO3) to 5mL of dilute hydrochloric acid (HCl) in a test tube.

Word equations : Equations in word Copper sulfate+ Zinc → Zinc sulfate + Copper Zn + CuSO4 → ZnSO4 + Cu Calcium hydroxide + carbon dioxide → calcium carbonate + water Ca(OH)2 + CO2 →  CaCO3 + H2O Copper Carbonate (CuCO3) + Heat → Copper oxide(black powder CuO) + carbon dioxide(CO2) Barium chloride (BaCl2) + Sulphuric acid (H2SO4) → Barium sulphate (BaSO4) + Hydrochloric acid (HCl) Lead nitrate (Pb(NO3)2) + Potassium iodide(KI) → Lead iodide + Potassium nitrate Sodium carbonate(Na2CO3) + Hydrochloric acid (HCl) → Sodium chloride + water + carbon dioxide

If the empty space was taken out of all atoms If the empty space was taken out of all atoms... the 7 billion people on Earth… would be the volume of a sugar cube!

Atoms, Ions and Molecules Lesson aims: To understand how chemical reactions take place. To know how covalent, ionic and metallic bonding occur.

Vocabulary Review Backs to the boards… (But before we start, you have 3 minutes to review our last Chemistry unit!)

METAL

PERIODIC TABLE

ATOM

ELECTRONS

VALENCE ELECTRONS

Nucleus

Reading Race! …with a difference. I will give you the answer, you have to write the question! For example: Answer = Ms. Lee Question? Who is the most awesome teacher in the world, with beautiful long hair and a wonderful personality. And she is very nice and funny too.

ANSWER: atoms, ions or molecules QUESTION: What is all matter made of?

ANSWER: Element. QUESTION: What is the name give for an atom that presents the unique property of the kind? There are more than 110 kinds being discovered so far.

ANSWER: It depends on how many valence electrons there are in its outer shell. QUESTION: What decides the type of bond an atom will form?

ANSWER: They try to get a full outer shell by losing, gaining or sharing valence electrons. QUESTION: Why/How do atoms bond?

Not in your book… ANSWER: For most elements, 8. QUESTION: How many electrons are there in a complete outer shell?

Obtaining a Complete Outer Shell For the following elements, how many electrons do they need for a full outer shell?

Oxygen Atomic number = 8 Electron configuration = 2,6 O needs 2 more electrons Chemical reactions = bonding = atoms obtaining a complete outer shell

Magnesium Atomic number = 12 Electron configuration = 2,8,2 Mg needs to lose 2 electrons Chemical reactions = bonding = atoms obtaining a complete outer shell

Sodium Atomic number = 11 Electron configuration = 2,8,1 Na needs to lose 1 electron Chemical reactions = bonding = atoms obtaining a complete outer shell

Hydrogen Atomic number = 1 Electron configuration = 1 H needs to gain 1 electron more… OR to lose 1 electron! Chemical reactions = bonding = atoms obtaining a complete outer shell

Chlorine Atomic number = 17 Electron configuration = 2,8,7 needs 1 more electron Chemical reactions = bonding = atoms obtaining a complete outer shell

Argon Atomic number = 18 Electron configuration = 2,8,8 It doesn’t need to do anything  What is the name given for the group this gas belongs to in the Periodic table? Chemical reactions = bonding = atoms obtaining a complete outer shell

Do you remember what they are? CORE electrons: Electrons that are in full shells. If we use the example of Na (sodium) , the electrons in the first shell ( 2 electrons) and the electrons in the second shell ( 8 electrons) are both found in full shells. These are the core electrons. VALENCE electrons: The valence shell of the atom is the outermost shell that contains electrons. Electrons in the outermost shell are called valence electrons.

Three Types of Bonds The 3 main types of bond are: (find them!) COVALENT Bonds METALLIC bonds IONIC bonds Chemical reactions = bonding = atoms obtaining a complete outer shell

Covalent Bonding What is happening here: Chemical reactions = bonding = atoms obtaining a complete outer shell

Covalent Bonding Key facts: Between non-metal and non-metal compounds. It is the sharing of electrons. Creates molecules. Chemical reactions = bonding = atoms obtaining a complete outer shell

Covalent Bonded Molecules Using the Molymods, create the following molecules… Chemical reactions = bonding = atoms obtaining a complete outer shell

An oxygen molecule Chemical reactions = bonding = atoms obtaining a complete outer shell

A hydrogen molecule Chemical reactions = bonding = atoms obtaining a complete outer shell

A carbon dioxide molecule Chemical reactions = bonding = atoms obtaining a complete outer shell

A water molecule Chemical reactions = bonding = atoms obtaining a complete outer shell

Molecules MOLECULES are 2 or more atoms bonded together in a covalent bond. For example, water, oxygen, hydrogen, glucose even DNA. H2O C6H12O6 O2 H2 Chemical reactions = bonding = atoms obtaining a complete outer shell

Metallic Bonding What’s happening? VALENCE ELECTRONS FREELY MOVING SEA OF ELECTRONS

Metallic Bonding The valence electrons of the metal atoms move around freely between atoms creating a “sea of electrons”. Because the metal atoms loses electrons to the sea, they are positively charged (why?). The positive metal IONS are attracted to the negative electrons = METALLIC BONDING.

Ionic Bonding How would sodium and chlorine complete an outer shell? Na: 2,8,1 (lose one) Cl: 2,8,7 (gain one)

(2 minutes) Tell each other again…

QUESTION RACE Page 75, GO!!!

Atoms, Ions and Molecules Lesson aims: To understand how chemical reactions take place. To know how covalent, ionic and metallic bonding occur.

Chemical Salts Lesson aims: To know what happens when a metal and acid react.

Which Salt? Salts have many uses. For example, which salt is used as a flavour enhancer? Table salt = sodium chloride! Which salt makes you poop a lot? Which salt is used to make fluffy pancakes? Which salt is used to help plants grow? Which salt is used for drawing on blackboards?

Three Reactions To Learn metal + acid metal oxide + acid metal carbonate + acid Let’s see what happens!!

Metals + Acid What happens when we react a metal with an acid? Try it and observe… Magnesium and dilute sulphuric acid (write down your observations) How do we know what gas it is? SET FIRE TO IT!!!

POP!! Collect the gas like this as seen on p77. When collected, put a burning splint into the gas (don’t let it escape). POP!! = H2

Try to write a word formula: magnesium + sulphuric acid  magnesium sulphate + hydrogen Mg + H2SO4  MgSO4 + H2

Other Acids magnesium + various acid  salts + hydrogen magnesium + sulphuric acid  magnesium sulphate + hydrogen magnesium + hydrochloric acid  magnesium chloride + hydrogen magnesium + nitric acid  magnesium nitrate + hydrogen

Metal Oxides + Acids copper oxide + sulphuric acid  ?? Write down your observations. copper oxide + sulphuric acid  copper sulphate + water CuO + H2SO4  CuSO4 + H2O

Summary so far… Metal + acid  Metal oxide + acid 

Metal Carbonate + Acid CaCO3 + H2SO4  CaSO4 + CO2 + H2O calcium carbonate + sulphuric acid  calcium sulphate + carbon dioxide + water

Summary Metal + acid  Metal salt + hydrogen Metal oxide + acid  Metal salt + water Metal carbonate + acid  Metal salt + carbon dioxide + water