Bonding
Structure and bonding
Ionic bonding
Covalent bonding
Metallic bonding
Giant covalent bonding
Properties
Ionic bonding
Covalent bonding
Metallic bonding
Giant covalent bonding
malleable and ductile
High melting and boiling points, so it require a lot of heat
energy to break up the lattice.
Metals and non-metals react together to form ionic compound
Non-metals react together to form covalent compounds.
Ionic compounds are usually soluble in water.
When ionic compounds melted or dissolved in water, they conduct electricity
Low melting and boiling points
Covalent compounds tend to be insoluble in water.
Covalent compounds do not conduct electricity
usually have high melting points.
e good conductors of heat and electricity.
Chemical formulas and reactions
Formula
Example: Magnesium chloride
The ions form a lattice with two chloride ions for each magnesium ion.
So the formula of the compound is MgCl2. It has no overall charge.
Reactions
Example: carbon is heated
in oxygen, they react together to form carbon dioxide
Word equation: carbon + oxygen --> carbon dioxide
Chemical equation: C + O2 -->CO2
Mole concept and chemical calculation
Balance of equation and conservation of mass
The law of conservation of mass states that no atoms are lost or made in a chemical reaction. That's why the number of each type of atom must the same on both sides
The sum of the reactants is equal to the sum of the product
Solid
Liquid
Gas
Moles = Concentration x volume
Moles = Volume/Molar volume(24)
Moles = Mass/Molar mass
Reaction kinetics
Rates
Rate is a measure of the change that happens in a single unit of time.
Factors affects rates
concentration of a reactant
How to measure
the amount of a reactant used up per unit of time or
the amount of a product produced per unit of time.
temperature
surface area of a solid reactant
Energy change and reversible reaction
Energy changes in reactions
Exothermic reactions
Exothermic reactions give out energy. So there is a temperature rise.
Endothermic reactions
Endothermic reactions take in energy from their surroundings.
the products have lower energy than the reactants.
the products must have higher energy than the
reactants.
Breaking bonds takes in energy. Making bonds releases energy
Reversible reaction
A reversible reaction is endothermic in one direction, and exothermic
in the other. The same amount of energy is transferred each time.
equilibrium
When a reversible reaction is in equilibrium and you make a change,
the system acts to oppose the change, and restore equilibrium.
For exothermic, when the temperature increase equilibrium favours the product.
For endothermic, when the temperature increase equilibrium favours the reactants.
if the concentration of reactants is increased, the system will shift toward the products. If more products are added, the system will shift to form more reactants
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combustion of fuels
Fuels are substances that react with oxygen to release useful energy
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When elements has same bonding, same electron configuration. So the different isotopes will react in the same way