Chemical Equations

HideShow resource information

Atoms are not Lost or Made in Chemical Reactions

During chemical reactions the two atoms you had the beginning will be at the end.

Check that the equation is balanced 

Balanced symbol equations show the atoms at the start(the reactant atoms) and the atoms at the end ( product atoms) and how they are arranged

                Word Equation: Sodium + Chlorine ----> sodium chloride 

Balanced Symbol equation: 2Na(s)  + Cl2(g)   -----> 2NaCl(s)

The small letters after the symbol are state symbols 

(s) Solid 

(l) Liquid

(g) Gas 

(Aq) Dissolved in water

1 of 3

Balancing the equation

Match them up one by one

There must always be the same number of atoms on both sides - they cannot just dissapear.

You balance the equation by putting numbers in front of the formulas where needed 

For Example

Na(s) + H2O(I) -----> NaOH(aq) + H2(g)

The formulas are all correct but the numbers of some atoms don't match up on both sides

You can't change formulas like H2O to H3O. You can only put numbers in front of them. 

2 of 3

Method: Balance just ONE type of atom at a time

Find an element that doesn't balance and pencil in a number to try and sort it out.

See where it gets you. It may create another imblanace - if so, just pencil in another number and see where that gets you.

Carry on chasing and unbalanced elements and it'll sort itself out pretty quickly.

Repeat process.

Na(s) + H2O(I) -----> NaOH(aq) + H2(g)

This needed to be 

2Na(s) + 2H2O(I) -----> 2NaOH(aq) + H2(g)

3 of 3

Comments

No comments have yet been made

Similar Chemistry resources:

See all Chemistry resources »See all Chemical patterns and reactivity series resources »