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How many moles are there in 3.0 g of \(O_2\)? [O = 16.0]

Chemistry
WAEC 2023

How many moles are there in 3.0 g of \(O_2\)? [O = 16.0]

  • A. 0.0093 moles.
  • B. 0.0930 moles.
  • C. 0.0625 moles.
  • D. 0.6250 moles.
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Correct Answer: Option B
Explanation

Number of moles = Mass / Molar mass
Given that the molar mass of oxygen \(O_2\) is 32.0 g/mol (2 × 16.0 g/mol), you can calculate the number of moles:
Number of moles = 3.0 g / 32.0 g/mol = 0.09375 moles
Rounded to four significant figures, the number of moles in 3.0 g of O2 is approximately 0.0938 moles.
Therefore, the closest answer choice is:
0.0930 moles.


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WAEC Past Questions, Objective & Theory, Study 100% offline, Download app now - 24709
NECO June/July 2024 - Get offline past questions & answers - Download objective & theory, all in one app 48789
Post-UTME Past Questions - Original materials are available here - Download PDF for your school of choice + 1 year SMS alerts
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Post-UTME Past Questions - Original materials are available here - Download PDF for your school of choice + 1 year SMS alerts
WAEC Past Questions, Objective & Theory, Study 100% offline, Download app now - 24709
Join your school's WhatsApp group
NECO June/July 2024 - Get offline past questions & answers - Download objective & theory, all in one app 48789