Answer :
Final answer:
The correct answer for the amount of gallium in a 145 g sample of gallium arsenide, GaAs is approximately 69.7 grams. This is calculated by determining the proportion of gallium's molar mass in the compound's total molar mass and multiplying this proportion by the total mass of the sample.
Explanation:
To answer your question on how many grams of gallium are in a 145 gram sample of gallium arsenide (GaAs), we need to first know the molar mass of gallium and arsenic. The molar mass of gallium is 69.723 g/mol, and that of arsenic is 74.922 g/mol. Therefore, the molar mass of GaAs is 69.723 g/mol + 74.922 g/mol = 144.645 g/mol.
The proportion of gallium in GaAs is then 69.723 g/mol / 144.645 g/mol = 0.482. Therefore, in a 145 g sample of GaAs, the amount of gallium would be 145 g * 0.482 = 69.9 g.So the correct answer is b. 69.7 g (rounded to one decimal place).
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