The student filters and dries the precipitate of CaCO3 (molar mass 100.1 g/mol) and records the data in the table below. Determine the number of moles of Na2CO3 in the original 50.0 mL of solution.
Volume of Na2CO3 solution: 50 mL
Volume of 0.1 M Ca(NO3)2: 100 mL
Mass of CaCO3 precipitate collected: 0.93 g

the mass of the cathode increases because ions from the solution get reduced to atoms and become part of the cathode.

explanation:

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answer:

the answer is 6 valence electrons.

explanation:

valence is the # of electrons on the outer most shell of an atom.

oxygen has 6.

although, the valency of oxygen is 2, because it only needs to make 2 covalent bonds, or gain 2 electrons, to achieve the stable octet configuration of a noble gas.

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