Chemistry – Stoichiometry - The mole and the Avogadro constant | e-Consult
Stoichiometry - The mole and the Avogadro constant (1 questions)
Login to see all questions.
Click on a question to view the answer
Calculation:
- Calculate the moles of HCl used: moles = concentration x volume (dm3). Volume of HCl = 20.0 cm3 = 0.020 dm3. Concentration = 0.200 mol/dm3. Therefore, moles of HCl = 0.200 mol/dm3 x 0.020 dm3 = 0.004 moles.
- Use the stoichiometry of the reaction to find the moles of Mg(OH)2: From the balanced equation, 1 mole of Mg(OH)2 reacts with 2 moles of HCl. Therefore, moles of Mg(OH)2 = 0.004 moles HCl / (2 moles HCl / 1 mole Mg(OH)2) = 0.002 moles Mg(OH)2.
- Calculate the concentration of the Mg(OH)2 solution: Concentration = moles / volume (dm3). Volume of Mg(OH)2 solution = 25.0 cm3 = 0.025 dm3. Therefore, concentration of Mg(OH)2 = 0.002 moles / 0.025 dm3 = 0.08 mol/dm3.
Answer: The concentration of the Mg(OH)2 solution is 0.08 mol/dm3.