Selenium, an element used in the manufacture of solar energy devices, forms an oxide that contains only one atom of selenium (per formula unit) and one or more oxygen atoms' The oxide that is formed has 37 8% oxygen by mass What is the molecular formula of the oxide?

Angelo knows the amount of a compound in moles. To find the number of molecules in the sample of compound, which of the following values must be used in the calculation? D molar mass of the compound atomic mass of each element in the compound mass of the sample in grams Avogadro's number Calculate the number of formula units present in a sample that contains 3.2 moles of potassium chloride. number of units: MacBook Pro + formula units

Vitamin C contains 40.92% C, 4.58% H, and 54.5% O by mass. What is the empirical formula of vitamin C?

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A hydrocarbon contains 85.7% Carbon by mass. Its molar mass is approximately 42 g/mol    a) What's the other element and What's its mass percent b) What's the empirical formula?  c) What's the molar mass of the empirical formula?

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