The law of conservation of mass states that mass is neither created nor destroyed during a chemical reaction. this can be gleaned from the third postulate in dalton's series. magnesium oxide decomposes into magnesium and oxygen. if 16.12 g of magnesium oxide decomposes to form 9.72 g of magnesium, what mass of oxygen gas is also released in the reaction?

Answer : The total mass of oxygen gas released in the reaction will be, 12.8 grams

Explanation :

Law of conservation of mass : It states that mass can neither be created nor be destroyed but it can only be transformed from one form to another form.

This also means that total mass on the reactant side must be equal to the total mass on the product side.

The balanced chemical reaction will be,

According to the law of conservation of mass,

Total mass of reactant side = Total mass of product side

Total mass of = Total mass of

or,

Total mass of = Mass of  + Mass of

As we are given :

Total mass of = 16.12 grams

The mass of = 9.72 grams

So,

Total mass of = Mass of  + Mass of

Therefore, the total mass of oxygen gas released in the reaction will be, 12.8 grams

given:

mass of na = 115 g

excess cl2

to determine:

mass of nacl produced

explanation:

given reaction is-

2na(s) + cl2(g) → 2nacl(s)

since cl2 is in excess, na will be the limiting reagent

as per the reaction stoichiometry na: nacl = 1: 1

i.e. moles of na reacted = moles of nacl formed

now, # moles of na = mass of na/atomic mass

                                  = 115 g/23 g.mol-1 = 5 moles

therefore, moles of nacl = 5

molar mass of nacl = 58 g/mol

mass of nacl = 5 moles * 58 g.mol-1 = 290 g

ans: amount of nacl produced = 290 g