Question

A chemistry graduate student combines 4.0 grams of potassium and 13.0 grams
of iodine to form potassium iodide. According to the law of conservation of mass,
how much potassium iodide should be formed if the reaction proceeds to
completion?

Answer 1

Answer:

when the reaction is complete 17 g product must be obtain.

Explanation:

Law of conservation of mass:

According to the law of conservation mass, mass can neither be created nor destroyed in a chemical equation.

Explanation:

This law was given by french chemist  Antoine Lavoisier in 1789. According to this law mass of reactant and mass of product must be equal, because masses are not created or destroyed in a chemical reaction.

For example:

In given reaction,

2K  + I₂     →    2KI

4 g + 13.0 g  =  17 g

 17 g        =   17 g

So when the reaction is complete 17 g product must be obtain because the amount of reactants were 17 g and according to law of conservation of mass ,mass can neither be created nor destroyed in a chemical equation but only convert from one to another form.

Another example:

In  photosynthesis reaction:

6CO₂ + 6H₂O + energy → C₆H₁₂O₆ + 6O₂

there are six carbon atoms, eighteen oxygen atoms and twelve hydrogen atoms on the both side of equation so this reaction also followed the law of conservation of mass.