Question

give the correct formula for barium chloride. express your answer as a chemical formula. part b calculate the formula mass for barium chloride. express your answer in atomic mass units to two decimal places. part c give the correct formula for dinitrogen pentoxide. express your answer as a chemical formula.

Explanation:

Part A:

Step1: Determine ions

Barium (\(Ba\)) forms \(Ba^{2 + }\) ion (group 2 metal, loses 2 electrons). Chloride (\(Cl\)) forms \(Cl^{-}\) ion (group 17 non - metal, gains 1 electron).

Step2: Balance charges

To balance the charges (\(+ 2\) from \(Ba^{2+}\) and \(-1\) from \(Cl^{-}\)), we need 2 \(Cl^{-}\) ions for each \(Ba^{2+}\) ion.

Part B:

Step1: Find atomic masses

Atomic mass of \(Ba = 137.33\) amu, atomic mass of \(Cl=35.45\) amu.

Step2: Calculate formula mass

Formula mass of \(BaCl_{2}=137.33+(2\times35.45)\)

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Part C:

Step1: Analyze prefixes

“Dinitrogen” means 2 nitrogen (\(N\)) atoms. “Pentoxide” means 5 oxygen (\(O\)) atoms.

Answer:

• Part A: \(BaCl_{2}\)
• Part B: \(208.23\) amu
• Part C: \(N_{2}O_{5}\)