Calculate % of N in KNO3__________?
Correct answer: C. 13.86%
- A. 14.34%
- B. 18.56%
- C. 13.86%
- D. None of these
Explanation
The molar mass of KNO3 is 39.10 g/mol + 14.01 g/mol + 3 x 16.00 g/mol = 101.11 g/mol. Percentage of nitrogen = (14.01 g/mol ÷ 101.11 g/mol) x 100 = 13.86%, so option c fits; 14.34% usually results from using an incorrect formula mass.
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The mole connects the microscopic number of particles with measurable mass, using Avogadro's number, 6.022 × 10²³ particles per mole. Questions involve molar mass, conversion between mass, moles and particles, percentage composition, empirical and molecular formulas, and distinguishing atoms, molecules, ions and formula units.
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