A sample of calcium oxide (CaO) has a mass of 2.80 g. The molar mass of CaO is 56.08 g/mol. How many moles of CaO does this sample contain? 0.0499
20.0
58.9
157

0.0499

Explanation:

Got it from quizlet and it was correct on my test.

it's c. elements are placed in rows based on how may valencies electrons have.

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