Final answer:
To calculate the moles of HCl in 19.6 mL of stomach acid with a molarity of 1.45×10-2 M, you multiply the volume in liters (0.0196 L) by the molarity, resulting in 2.842×10-4 moles of HCl.
Step-by-step explanation:
The student is asking how to calculate the number of moles of HCl in a 19.6 mL sample of stomach acid with a molarity of 1.45×10-2 M. To find the moles of HCl, we use the formula: moles = molarity × volume in liters. First, convert 19.6 mL to liters by dividing by 1000: 19.6 mL × (1 L / 1000 mL) = 0.0196 L. Then, multiply the volume in liters by the molarity of the solution: 1.45×10-2 M × 0.0196 L = 2.842×10-4 moles of HCl.