Conservation of Mass Flashcards

All 5 cards in this deck

State the law of conservation of mass.

The total mass of the products equals the total mass of the reactants; no atoms are created or destroyed in a chemical reaction.

Why does the mass not change in a precipitation reaction carried out in a closed flask?

No gas enters or leaves, so all the atoms stay in the closed system.

Why does the mass decrease when a metal carbonate is heated in an open flask?

A gas (carbon dioxide) is given off and escapes from the non-enclosed system.

Why does the mass increase when a metal is heated in air in an open crucible?

The metal combines with oxygen from the air, which adds to the mass of the solid.

True or false? A decrease in mass during a reaction in an open flask means the law of conservation of mass has been broken.

False. Mass is still conserved — a gas has escaped into the surroundings.