Reaction Equation

Reaction Equation The reaction equation describes a chemical reaction, consisting of a chemical formula reactants and reaction products, accompanied by their respective coefficients and phases. Write the Reaction Equation Chemical reactions change the original substances (reactants) into new substances (products). As stated by John Dalton, the type and number of atoms involved in the reaction does not change, but the chemical bonds between them do changed. Chemical bonds in the reactants are broken and new bonds are formed in the product. The atoms rearrange to form reaction products. Change What happened can be described using the chemical formulas of the substances involved in the reaction. This way of exposure we call the reaction equation. The things described in the reaction equation are the chemical formulas of the reactants (reactants) to the left of the arrow and the products of the reaction (products) to the right of the arrow. The arrows are read which means "to form" or "to react to become". There are four types of states or states of the reactants and reaction products, namely gas (g), liquid (liquid or l), solid (solid or s) and solution (aqueous or aq). The number that precedes the chemical formula of the substances in the reaction equation is called the reaction coefficient. Reaction coefficients are given to balance the atoms before and after the reaction. In addition to balancing the reaction equation, the reaction coefficient expresses the simplest ratio of the particles of substances involved in the reaction. For example, the reaction between hydrogen gas and oxygen gas to form water is as follows. Reactants or reactants Reaction results/products 2H2 ( g) coefficient H2 = 2 + O2 (g) coefficient O2 = 1 2 H2 O(l) coefficient H2O = 2 Based on the above reaction equation, it means that 2 hydrogen molecules react with 1 oxygen molecule to form 2 H2O molecules . Therefore, the fractional coefficient should be avoided because it can give an understanding as if the material particles (atoms or molecules) can be broken down. Writing the reaction equation can be done in two steps as follows. 1. Write down the chemical formulas of the reactants and products, complete with a description of their forms. 2. Equalization, namely giving the appropriate coefficient, so that the number of atoms on the left side is equal to the number of atoms on the right side. Example : Write and balance the equation for the reaction between aluminum metal which reacts with a solution of sulfuric acid to form a solution of aluminum sulfate and hydrogen gas! Answer: Step 1 : Write down the reaction equation. Al(s) + H2 SO4 (aq) Number of atoms on the left side: Al = 1 H=2 S=1 O=4 Al2 (SO4 ) 3 (aq) + H2 (g) (not yet equivalent) Number of atoms on the right side: Al = 2 H=2 S=3 O=12 Step 2 : Place the coefficient 2 in front of Al, so that the number of Al atoms on the left side becomes 1 × 2 = 2 Al (equivalent to the number of Al on the right side). Step 3 : Put the coefficient 3 in front of H2SO4 , so that on the left side the number of H atoms becomes 6, S atoms become 3, and the number of O atoms becomes 12 . Step 4 : The number of S and O atoms on the left side is the same as on the right side, while the H atoms on the right side are not equal to the left side. Step 5 : Put the coefficient 3 in front of H2 , so that the number of H atoms is the segment right side becomes 6, equivalent to the left side. The reaction equations become balanced: 2 Al(s) + 3 H2 SO4 (aq) Al2 (SO4 )3 (aq) + 3 H2 (g) Because Al2 (SO4 )3 not added to the coefficient, means the coefficient of Al2 (SO4 )3