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Covalent (sharing of electron pairs) · 2015-01-04 · Properties ( simple covalent) low melting...

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Page 1: Covalent (sharing of electron pairs) · 2015-01-04 · Properties ( simple covalent) low melting points and low boiling points ... compound is equal to the relative formula mass in
Page 2: Covalent (sharing of electron pairs) · 2015-01-04 · Properties ( simple covalent) low melting points and low boiling points ... compound is equal to the relative formula mass in

Covalent (sharing of electron pairs)

Ionic ( electrostatic attraction between oppositely charged ions)

Metallic (electrostatic attraction between + metal ions and delocalised electrons)

Page 3: Covalent (sharing of electron pairs) · 2015-01-04 · Properties ( simple covalent) low melting points and low boiling points ... compound is equal to the relative formula mass in

Group 1 ions 1+ Group 2 ions 2+ Group 3 ions 3+ Group 4 ions 4-/+ Group 5 ions 3-/5+ Group 6 ions 2- Group 7 ions 1-

Magnesium chloride Magnesium 2+ Chloride 1- Formula:

Magnesium oxide Magnesium 2+ Oxide 2- Formula:

Aluminium oxide: Calcium nitrate: Sodium carbonate: Potassium sulphate: Aluminium sulphate: Aluminium hydroxide:

Other ions: Ammonium Carbonate Nitrate Sulphate Hydroxide

Properties Solids High melting points and high boiling points Don't conduct as solids Conduct when molten or dissolved

Explanations ...................................................... ...................................................... ...................................................... ...................................................... ...................................................... ......................................................

Page 4: Covalent (sharing of electron pairs) · 2015-01-04 · Properties ( simple covalent) low melting points and low boiling points ... compound is equal to the relative formula mass in

Properties High melting points and high boiling points Good conductors of heat Good conductors of electricity

Explanations ...................................................... ...................................................... ...................................................... ...................................................... ...................................................... ......................................................

Properties ( simple covalent) low melting points and low boiling points

Explanation ...................................................... ...................................................... ...................................................... ...................................................... ......................................................

Properties ( giant covalent) high melting points and high boiling points Diamond is hard Diamond does not conduct Graphite is slippery & soft Graphite conducts electricity

ExplanationS ...................................................... ...................................................... ...................................................... ...................................................... ...................................................... ...................................................... ...................................................... ...................................................... ...................................................... ...................................................... ...................................................... ......................................................

Page 5: Covalent (sharing of electron pairs) · 2015-01-04 · Properties ( simple covalent) low melting points and low boiling points ... compound is equal to the relative formula mass in

Nano tubes and fullerenes

Nano science applicationS Uses: Pros: Cons:

1nm=

Page 6: Covalent (sharing of electron pairs) · 2015-01-04 · Properties ( simple covalent) low melting points and low boiling points ... compound is equal to the relative formula mass in

High density polymer Low density polymer

Thermosoftenig polymer Properties: Explanation:

Thermosetting polymer Properties: Explanation:

Uses: Uses:

Uses:Uses:

Formed from same monomer under different conditions (temperatures, pressures, catalysts)

Page 7: Covalent (sharing of electron pairs) · 2015-01-04 · Properties ( simple covalent) low melting points and low boiling points ... compound is equal to the relative formula mass in

Relative formula mass Find the atomic mass of each element in the compound and add up all formula masses. Water: Calcium carbonate: Aluminium hydroxide: Aluminium sulfate: Ammonium carbonate:

percentage by mass calculations Example: what is the % by mass of hydrogen in water? There are two hydrogen atoms in water with a total atomic mass of 2. The formula mass of water is 18. The percentage mass of hydrogen is therefore 2/18 x100 = 11% Find the % by mass of oxygen in each compound Calcium carbonate: Aluminium hydroxide: Aluminium sulfate: Ammonium carbonate:

a mole Each atom has a tiny mass and it is difficult to measure The mass. It is easier to find the mass of many atoms. Scientists have found the mass of 6.023 x1023 many atoms. This number is called 1 mole. The mass of one mole of an atom is equal to the atomic mass in grams. The mass of one mole of a compound is equal to the relative formula mass in grams. 1 mole of water = 1 mole of carbon dioxide = 1 mole of potassium iodide =

Page 8: Covalent (sharing of electron pairs) · 2015-01-04 · Properties ( simple covalent) low melting points and low boiling points ... compound is equal to the relative formula mass in

empirical formula

the empirical formula is the simplest ratio of elements in a compound.

empirical formula & molecular formula

Switching between the two using the respective formula masses:

finding he empirical formula from % by mass or mass

What are the steps?

Page 9: Covalent (sharing of electron pairs) · 2015-01-04 · Properties ( simple covalent) low melting points and low boiling points ... compound is equal to the relative formula mass in

A compound contains 39.4% by mass of iron and the rest is oxygen. What is the empirical formula?

If 1.27gRams of copper made 1.59grams of copper oxide, what is the empirical formula of the copper oxide formed?

Reacting mass calculations

using the relative formula masses and the idea of moles we can calculate the amounts of products and reactants for a chemical reaction:

How much carbon dioxide would be produced from 6 grams of carbon? How much oxygen would you need?

How much carbon do you need to produce 169.84 grams of carbon dioxide?

Page 10: Covalent (sharing of electron pairs) · 2015-01-04 · Properties ( simple covalent) low melting points and low boiling points ... compound is equal to the relative formula mass in

Copper oxide reacts with sulfuric acid to form copper sulphate And water. If 1.59 grams of copper oxide were used, how much copper sulphate is made?

Sulphur reacts with oxygen to form sulphur trioxide. If 100 tOnnes of sulphur are burnt in a day, how much sulphur trioxide is produced in a week?

Percentage yield

The student produced 2.2 grams of copper sulphate Instead of 2.8 grams. What is the percentage yield?

Percentage yield- why not always 100% ?

1.

2.

3.

4.

5.

Page 11: Covalent (sharing of electron pairs) · 2015-01-04 · Properties ( simple covalent) low melting points and low boiling points ... compound is equal to the relative formula mass in

Hydrated copper sulphate vs dehydrated copper sulphate

the forward reaction is endothermic as you need to supply heat to remove the water. water is given off as steam.

The backward reaction is exothermic. Some of the water added evaporates as

a large amount of heat is released.

Definition: Temperature of surroundings: Energy profile diagram:

Definition: Temperature of surroundings: Energy profile diagram:

Page 12: Covalent (sharing of electron pairs) · 2015-01-04 · Properties ( simple covalent) low melting points and low boiling points ... compound is equal to the relative formula mass in

Rate definition: Collision theory:

Factors that affect the rate of reacion- explanations

Concentration

Temperature

Surface area

Catalyst

Page 13: Covalent (sharing of electron pairs) · 2015-01-04 · Properties ( simple covalent) low melting points and low boiling points ... compound is equal to the relative formula mass in

How to find the rate experimentally

Things to look out for:

....... amounts of reactants used so ....... total amount of product made.

....... the amount of reactant used So ....... the amount of product made.

Page 14: Covalent (sharing of electron pairs) · 2015-01-04 · Properties ( simple covalent) low melting points and low boiling points ... compound is equal to the relative formula mass in

Acids are proton.............................Bases are proton ............................ The four types of bases are: ................................................................. Bases that are soluble in water are called alkalis. Alkalis form oh- ions in solution and tend to be metal hydroxides and ammonia.

Acids react with bases to make salts. Hydrochloric acid makes ..............salts Sulphuric acid makes ...................salts Nitric acid makes ........................salts Ammonia makes ..........................salts

When acids and bases react, the products can differ: Acid + metal oxide ->.............................. Acid + metal carbonate -> ...................... Acid + metal hydroxide -> ....................... Acid + ammonia -> .................................. Examples: .......................................................... .......................................................... .......................................................... ..........................................................

Acids react with alkalis to make salt and water. The ionic equation for all acid-alkali reactions is: ........................................................................................................

Useful salts: Sodium chloride............................................ Epsom salt (Magnesium sulphate).................... ................................................................. Ammonium nitrate..........................................

Page 15: Covalent (sharing of electron pairs) · 2015-01-04 · Properties ( simple covalent) low melting points and low boiling points ... compound is equal to the relative formula mass in

Salt preparation method

Soluble salt Insoluble salt

Titration ( acid + alkali)

Excess base method (insoluble base + acid)

Precipitation method

Soluble salt

Page 16: Covalent (sharing of electron pairs) · 2015-01-04 · Properties ( simple covalent) low melting points and low boiling points ... compound is equal to the relative formula mass in

Electrolysis means 'splitting a compound using electricity'.

Draw a labelled diagram to show how you would electrolyse molten lead bromide. Label and define the anode, cathode, anion, cation, electrolyte, oxidation, reduction.

Anode half equation (oxidation): Cathode half equation (reduction):

When an ionic compound is dissolved in water and the resulting solution is electrolysed, the products at the anode and cathode may differ depending on the position of the ions in the reactivity series.This is because water also consists of ions which are attracted to the anode and cathode.

Sodium chloride solution Cations present: Anions present: Cathode reaction: Anode reaction: Copper sulphate solution Cations present: Anions present: Cathode reaction: Anode reaction:

Page 17: Covalent (sharing of electron pairs) · 2015-01-04 · Properties ( simple covalent) low melting points and low boiling points ... compound is equal to the relative formula mass in

Important electrolysis case studies

Electrolysis of brine Electrolyte: Cathode reaction: Anode reaction: Overall equation: Products: Product uses: Diagram:

Electrolysis of bauxite Electrolyte: Cathode reaction: Anode reaction: Overall equation: Products: Anode replacement: Role of cryolite: Diagram:

Electroplating Electrolyte: Cathode reaction: Anode reaction: Overall equation: Products: Product uses: Diagram:

Copper purification Electrolyte: Cathode reaction: Anode reaction: Overall equation: Products: Product uses: Diagram:

Page 18: Covalent (sharing of electron pairs) · 2015-01-04 · Properties ( simple covalent) low melting points and low boiling points ... compound is equal to the relative formula mass in

Paper chromatography is used to separate colours in inks and dyes. Mobile phase:...................... Stationary phase:..................... How to prevent solvent from escaping:................................ Why to use pencil to draw base line:.................................... How to know which colour dissolved best:............................

How to set up the experiment. How to interpret the results.

gas chromatography is used to separate mixtures of Volatile liquids and gases. Mobile phase:...................... Stationary phase:..................... How mixture is separated:......................................................................... Meaning of retention time:........................................................................ How to interpret the chromatogram:..........................................................

The role of the mass spectrometer....


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