Answer: Moles of hydrogen required are 4.57 moles to make 146.6 grams of methane,
.
Explanation:
Given: Mass of methane = 146.6 g
As moles is the mass of a substance divided by its molar mass. So, moles of methane (molar mass = 16.04 g/mol) are calculated as follows.

The given reaction equation is as follows.

This shows that 2 moles of hydrogen gives 1 mole of methane. Hence, moles of hydrogen required to form 9.14 moles of methane is as follows.

Thus, we can conclude that moles of hydrogen required are 4.57 moles to make 146.6 grams of methane,
.
Centimeters are units of length.
Answer: B) 46.7% Si and 53.3% O
Explanation:
To calculate the mass percent of element in a given compound, we use the formula:

Mass of quartz
= 5.05 g
Mass of silicon = 2.36 g
Mass of oxygen = Mass of quartz
- mass of silicon = 5.05g - 2.36 g = 2.69 g


Thus the percentages of silicon and oxygen in quartz are B) 46.7% Si and 53.3% O