Question

question 10 (1 point)
what is the percentage, by mass, of oxygen in the compound u3o8? (note u 238 g/mol, o 16 g/mol)
17.9 %
30.4 %
35.0 %
15.2 %
72.7%

Explanation:

Step1: Calculate the molar mass of \(U_3O_8\)

The molar mass of \(U_3O_8\) is \(3\times238 + 8\times16\) g/mol.

$$3\times238+8\times16=714 + 128=842$$

g/mol.

Step2: Calculate the mass of oxygen in \(U_3O_8\)

The mass of oxygen in \(U_3O_8\) is \(8\times16 = 128\) g/mol.

Step3: Calculate the mass percentage of oxygen

The mass percentage of oxygen is \(\frac{128}{842}\times100\%\).

$$ \frac{128}{842}\times100\%=\frac{12800}{842}\% \approx 15.2\% $$

Answer:

15.2%