A glucose solution is prepared by dissolving 9.45 g of glucose in 168 g of water at 25 °C. What is the concentration of this solution in mass percent?

Hydrochloric acid is used to neutralize the ammonia produced from a Kjeldahl method where all nitrogen organic substances are converted to ammonia. In a 4.37 g sample of organic material, 23.0 mL of 0.280 M HCl (aq) was used up. Determine the mass percentage of nitrogen in the sample.

NH₃(aq) + HCl(aq) → NH₄Cl(aq)

Spectroscopy uses visible light to determine the absorbance of a compound. At 275 nm, a compound has an extinction coefficient of 8.40 × 10³ M^–1 cm^–1. Determine the molarity of the compound if it has an absorbance of 0.700 in a 1.00 cm sample cuvette.