difference between ionic equations and half equations

World Top Stories News - difference between ionic equations and half equations : Ionic equations have to be balanced and simplified as with all chemical equations, including molecular equations. Also note that the charges for ionic equations must also be balanced (ie the same on both sides). This is a good check in a test.

Consider the reaction between sulfuric acid and magnesium ribbon.
The molecular equation:
2 HNO3 (aq) + Mg (s) --> Mg(NO3)2 (aq) + H2 (g)
You probably already know how to find this.
Notice that the NO3- ions have not changed state throughout the reaction- these are spectator ions, and can be removed when writing ionic equations.
2 H+(aq) +Mg(s) --> Mg+2(aq) + H2(g)

The difference between a balanced ionic and a net ionic is quite simple really. Say we have 5 moles of Mg(s) and 10 moles of H+. The balanced ionic is 10 H+(aq) + 5 Mg(s) --> 5 Mg+2(aq) + 5 H2(g). It is then obvious to divide the coefficents by 5 to acheive the final answer.
2 H+(aq) +Mg(s) --> Mg+2(aq) + H2(g)

All equations must be balanced. If they feature ions, then the charges must also balance. (in the above, we have two +1 ions and one +2 ion on the other side, so both sides feature a charge of +2). Those equations in which the charges do not balance are called half-equations (and are balanced by adding e- (electrons)), but dont worry about these yet.

Relevant answers:
What is the difference between the molecular equation and the ionic equation?
The molecular equation is just a list of all atoms in a molecule - "NH3" is nitrogen + 3 hydrogen, for instance. The ionic equation also lists the charges of ions, and would generally be written...

What is the difference between complete ionic equations and net ionic equations?
A complete ionic equation shows all the ions even though some of them don't get involved with the reaction as spectator ions. A net ionic equation, on the other hand, shows only the ions that involve...

What is the difference between an equation and an expression?

What is the difference between a function and an equation?
A function describes a relation between several variables. For example the function f(x)=x2 describes a mapping from the variable x to a value that is the square of x. That is, for every real number

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