# Equations and Acids

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• Created by: Sophie
• Created on: 26-01-14 15:59

## Equations - Formulae (Ionic Compounds)

Ionic Compounds

• A ionic compound is a compound formed by ions onding together through electrostatic forces.
• Metal ions have a positive charge.
• Non-metal ions have a negative charge.

Formula of an ionic compound

• How to work out the formula:
• Write the formulae of the ions
• Adjust the number of each ion so that there is no overall charge.
• For Example:
• Magnesium Bromide: - ions are Mg2+ and Br-
• Need 2 x Br- to balance Mg2+
• Formula is MgBr2.
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## Equations - Formulae (Covalent Compounds)

Covalent Compounds

• A molecule formed by covalent bonds, in which the atoms share one or more pairs of electrons.
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## Ionic Equations

Ionic Equations

• Ionic equations leave out ions that are unchanged in a reaction.
• The unchanged ions are called spectator ions.

Example

HCl(aq) + NaOH(aq) ---> NaCl(aq) + H2O(l)

H+(aq) + OH-(aq) ---> H2O(l)

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## Acids

Acids

• An acid is a proton donor (H+ donor)
• Common acis are hydrochloric acid (HCl), sulphuric acid  (H2SO4), and nitric acid (HNO3).
• An acid releases Hions in aqueous solution.
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## Bases

Bases

• A base is a proton acceptor (H+ acceptor).
• Bases are metal oxides, metal hydroxides and ammonia solution.
• Bases destroy acidity in neutralisation reactions.
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## Alkalis

Alkali

• An alkali is a soluble base.
• Alkalis release OH- ions in aqueous solution.
• Common alkalis are sodium hydroxide, NaOH, potassium hydroxide, KOH, and aqueous ammonia, NH3.
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## Salts

Salts

• Salts are produced when the Han acid is replaced by another positive ion.
• Salts are formed when acids react with bases and carbonates.
• Observations when react:
• Fizzing
• Carbonate dissolves

Example

• Acid + carbonate ---> salt + water + carbon dioxide
• 2HCl(aq) + MgCO3(s) ---> MgCl2(aq) + H2O(l) + CO2(g)
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