acid + metal hydroxide salt + water
The name of a salt has two parts:
|Hydrochloric acid||Sulfuric acid||Nitric acid|
|Potassium hydroxide||Potassium chloride||Potassium sulfate||Potassium nitrate|
|Sodium hydroxide||Sodium chloride||Sodium sulfate||Sodium nitrate|
|Calcium hydroxide||Calcium chloride||Calcium sulfate||Calcium nitrate|
Write a word equation to describe the reaction between hydrochloric acid and sodium hydroxide.
hydrochloric acid + sodium hydroxide sodium chloride + water
To work out the formula of a salt you must know the charges of the ions involved.
|Common cations||Charge||Common anions||Charge|
|Hydrogen ion, H+||+1||Group 7 ions, e.g. Cl-||-1|
|Ammonium ion, NH4+||+1||Hydroxide ion, OH-||-1|
|Group 1 ions, eg K+, Na+||+1||Nitrate ion, NO3-||-1|
|Group 2 ions, eg Mg2+, Ca2+||+2||Carbonate ion, CO32-||-2|
|copper(II), Cu2+||+2||Carbonate ion, CO32-||-2|
|Iron(II), Fe2+||+2||Sulfate ion, SO42-||-2|
Transition metals can form ions with different charges, eg iron can form Fe2+ ions and Fe3+ ions. Their charges are shown in the name of the compound, eg iron(II) oxide and iron(III) oxide.
The formula for a compound must produce no overall charge. For example:
What is the formula of sodium sulfate?
Na2SO4 (two positive charges and two negative charges)
To write a balanced chemical equation first write the word equation. Replace the name of each compound with the correct formula.
CuCO3(s) + H2SO4(aq) CuSO4(aq) + CO2(g) + H2O(l)
Write a balanced chemical equation for the reaction of dilute sulfuric acid with sodium carbonate, Na2CO3.
H2SO4(aq) + Na2CO3(s) Na2SO4(aq) + CO2(g) + H2O(l)