12 gram of magnesium carbonate is heated till no for the loss of heat the final mass was found to be 5.28 gram how much CO2 gas was given out

12 g

Explanation:

Chemical equation:

MgCO₃      →        MgO  +  CO₂

12g           =           5.28g + 6.72 g

12 g           =            12 g

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

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.

MgCO₃      →        MgO  +  CO₂

There are 12 g of magnesium carbonate on the left side, according to the law of conservation of mass on the right side there should be 12 g product. Thus, 6.72 g of CO₂ should be formed.

i believe you are right for all except the 3rd ( look at sqdancefan his answer is much better)