Balancing Chemical Equations
In chemical reactions, the amounts of the different reactants and different products can sometimes be unequal to eachother. For example, when hydrogen (H2) and oxygen (O2) bond to form water (H20), one molecule of H2 and two molecules of O2 are used to form two molecules of H2O. So, to balance the equation of H2 + O2 -> H2O, you would need to add coefficients in front of the parts of the equation of which two or more are needed in order to make the equation equal, or balanced. Thus, that equation would become 2H2 + O2 -> 2H2O.
One way to check to make sure your equation is balanced is to count the number of atoms on either side of the equation and make sure the numbers for each element are equal. Remember that when subscripts (like this) are used, that means that there are as many atoms of the element that has the subscript as the number of the subscript. So H2 means that there are 2 molecules of Hydrogen. However, if coefficients are used, then that means there are a a certain number of the Molecule that the coefficient is before. So 2H2O indicates that there are two molecules of water as the product. Because of this, you have to double all the numbers of atoms for this molecule of water to make sure they balance. H2 means two hydrogen and O means one oxygen, doubled by the coefficient two means that the product of this reaction contains 4 molecules of Hydrogen and two of Oxygen. In the reactants side, there are two molecules of Oxygen (as indicated by O2) and four of Hydrogen (two in the subscript times two in the coefficient equals four total atoms). The numbers in each sides of the equation are equal, meaning that this equation is correctly balanced! Just make sure that all of your coefficients are completely reduced into the smallest multiples possible. So instead of 4H2 + 2O2 -> 4H2O, you divide all the coefficients by two to get the correct, most simplified answer.
One way to check to make sure your equation is balanced is to count the number of atoms on either side of the equation and make sure the numbers for each element are equal. Remember that when subscripts (like this) are used, that means that there are as many atoms of the element that has the subscript as the number of the subscript. So H2 means that there are 2 molecules of Hydrogen. However, if coefficients are used, then that means there are a a certain number of the Molecule that the coefficient is before. So 2H2O indicates that there are two molecules of water as the product. Because of this, you have to double all the numbers of atoms for this molecule of water to make sure they balance. H2 means two hydrogen and O means one oxygen, doubled by the coefficient two means that the product of this reaction contains 4 molecules of Hydrogen and two of Oxygen. In the reactants side, there are two molecules of Oxygen (as indicated by O2) and four of Hydrogen (two in the subscript times two in the coefficient equals four total atoms). The numbers in each sides of the equation are equal, meaning that this equation is correctly balanced! Just make sure that all of your coefficients are completely reduced into the smallest multiples possible. So instead of 4H2 + 2O2 -> 4H2O, you divide all the coefficients by two to get the correct, most simplified answer.