Question

Chemical equations are theoretical models of the rearrangements of individual atoms in chemical change.

Applying these models to the real world of the lab bench requires measuring out quantities of atoms and molecules in the same relative proportions as in the equation.

Explain why both a balanced equation and a periodic table are necessary to proceed from a theoretical equation to a predictable quantity of products.

Balanced Chemical equation helps us to predict how much of a product can be produced from given amount of the reactant or how much reactant is required to prepare a given amount of the product. Balanced chemical equation is based on law of conservation of mass and the periodic table is used to assign massed to different reactants of products.

   Use the following balanced chemical equation to illustrate your explanation.

2 Li(s) + CuCl₂(aq) => 2 LiCl (aq) + Cu (s)

How many grams of solid Copper can I produce if I use 28 grams of Lithium and excess amounts of copper II chloride? Explain your answer and show calculations.

Answer 1

molar mass of Li = 6.94 g / mole

molar mass of Cu =63.55 g / mole

2 Li +    CuCl2 ---------------------> 2 LiCl + Cu

2 x 6.941 g                                                           63.55 g

20 g                                                                        ?

2 x 6.941 g Li produce -------------------> 63.55 g Cu

20 g Li produce ----------------------> ?? g Cu

mass of Cu produced = 63.55 x 20 / 2 x 6.941

                                   = 91.6 g

solid copper produced = 91.6 g