Question

Which of the following does NOT show the law of conservation of mass?

A. 24 g of Mg burn in 32 g O2 to produce 56 g of MgO.

B. 24 mL of Mg burn in 32 mL O2 to produce 56 mL of MgO.

C. 2 atoms of Mg react with 1 molecule of O2 to produce 2 units of MgO.

D. 1 atom of Mg reacts with 1 atom of O to produce a unit of MgO that contains 2 atoms

Which of the following is a balanced chemical equation for the synthesis of NaBr from Na and Br2?

A. Na + Br2 → NaBr

B. 2Na + Br2 → NaBr

C. Na + Br2 → 2NaBr

D. 2Na + Br2 → 2NaBr