A beaker contains 9 g of water. The number of hydrogen atoms are:
Correct answer: A. 6.02 x 10^23
- A. 6.02 x 10^23
- B. 3.01 x 10^23
- C. 6.02 x 10^24
- D. 3.01 x 10^24
Explanation
Calculate the moles of H₂O in 9 g. moles (n) = mass (m)/molar mass (M) M(H₂O) = (2 × 1 g/mol H) + 16 g/mol O = 18 g H₂O/mol H₂O n(H₂O) = 9 g H₂O/18 g H₂O/mol H₂O = 0.5 mol H₂O In one mole of H₂O, there are two moles of H atoms. Calculate the moles of H atoms in 0.5 mol H₂O. 0.5 mol H₂O × 2 mol H atoms/1 mol H₂O = 1 mol H atoms Calculate the number of H atoms in 1 mole. 1 mole = 6.02 × 10²³ atoms 1 mole H atoms = 6.02 × 10²³ H atoms There are 6.022 × 10²³ atoms of hydrogen in 9 g of water.
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About Fundamental Concepts of Chemistry
Mole calculations connect mass, number of particles and Avogadro's number, while balanced equations provide the mole ratios used in stoichiometry. Questions cover limiting and excess reactants, theoretical yield and percentage yield, including identifying which reactant is consumed first and comparing the actual product with the maximum possible product.
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