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What does the Law of the Conservation of Matter state?
That matter (mass) can neither be created nor destroyed.
In chemical equations, the mass of the reactants must equal...
The mass of the products, regardless of whether the change is physical or chemical
How do you name simple compounds?
1. Write down the name of the metal (towards the left of the periodic table)
2. Write down the name of the non-metal, changing the ending of the word to -ide
Example - name this compound:
Magnesium + Oxygen =
Answer: Magnesium Oxide
Example - name this compound:
Sodium + Chlorine =
Answer: Sodium chloride
How do you write compounds containing 2 elements + oxygen?
do the exact same except the ending of the non-metal turns to -ate
Example - name this compound:
Nickel + Sulphur + Oxygen
Answer: Nickel Sulphate
Ions
positively and negatively charged atoms
Ionic bonding is when
electrons are transferred from one atom to another
Ionic bonding
When metal and non-metal atoms react together, they need to transfer atoms to fill outer shell and become.
Atoms with incomplete outer electron shells are unstable. By either __________ or _________ electrons, atoms can obtain full electron shells and become stable.
losing & gaining
Atoms that lose electrons have more protons and are hence more ____________ charged.
positively
Atoms that gain electrons, are more ________ charged.
negatively
Covalent bonding is when
atoms share electrons
Covalent bonding
When non-metal atoms react together, they need to gain electrons to fill their outer shell and become.
How can we show covalent and ionic bonding?
Lewis Diagram
Elements arranged vertically:
- groups
- each atom has the same number of electrons on the outermost shell
Elements arranged horizontally:
- periods
- the number of electrons shells an atom has
Acids are...
substances that produce hydronium ions when dissolved in water
Characteristics of acids
- taste sour
- react with many metals to form H2 gas
- are corrosive
- have a chemical formula that begins with H+
Example:
Zn(s) + 2HCl(aq) = ?
= ZnCl2 + H2
Common acids:
- citric acid, found in fruits & used as a preservative
- lactic acid, found in yogurt, produced by our muscles when they are overworked
- acetic acid, vinegar & used as a preservative
- carbonic acid or phosphoric acid found in soft drinks
Bases are
a substance that produces hydroxide (OH-) when placed in water
Base characteristics:
- taste bitter
- feel slippery
- are corrosive
- have a chemical formula ending in OH-
Common bases:
- ammonia, cleaners & fertilisers
- sodium hydroxide, soaps and drain cleaners
- magnesium hydroxide, ingredient found in antacids
Salts are...
Ions left behind after the H+ and OH- ions form water, combine to form salts.
Forms when negative ions from acid combine with positive ions from the base.
Example:
Acid + Base = ?
Salt + Water
Example:
HCl(aq) + KOH(aq) = ?
KCl(aq) + H2O