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    Working with molarity,molality and PH

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    If 4.oo mL of 0.0250 M CuSO4 is diluted to 10.0 mL with pure water, what is the molar concentration of copper (II) sulfate in the dilute solution?

    ______________________________ molar

    A 10.0-mL sample of 2.56 M HCL is diluted with water to 250. mL.

    What is the concentration of HCl in the diluted solution?

    Concentration of HCL______________________

    What is the pH of the dilute solution?

    ph of the dilute solution_______________________

    © BrainMass Inc. brainmass.com December 24, 2021, 4:55 pm ad1c9bdddf
    https://brainmass.com/chemistry/acids-and-bases/working-molarity-molality-ph-15858

    SOLUTION This solution is FREE courtesy of BrainMass!

    1. Dilution ==> V * M = V' * M'

    where M = Molarity before dilution
    V is volume of solution before dilution

    Or, 4*0.025 = 10*M' which gives M' = 4*0.025/10 = 0.01M ---Answer

    2. The most important thing to remember concerning dilution is that you are adding only solvent. You are not adding solute when you dilute. Therefore:

    moles of solute before dilution = moles of solute after dilution

    Molarity = moles of solute/volume of solution in liters

    Moles of solute = Molarity*liters of solution = 2.56*10 = 25.6

    New molarity = 25.6/250 = 0.1024 M ----Answer

    3.pH is a measure of the hydrogen ion concentration, [H+]

    pH is calculated using the following formula:

    pH = -log_10 [H+]

    Here we need to find the pH of a 0.1024M solution of HCl

    0.1024 mol L of HCl produces 0.1024 mol L-1 H+ since HCl is a strong acid that fully dissociates.

    thus, [H+] = 0.1024

    pH = -log_10[0.1024] = 0.9897 ---Answer

    This content was COPIED from BrainMass.com - View the original, and get the already-completed solution here!

    © BrainMass Inc. brainmass.com December 24, 2021, 4:55 pm ad1c9bdddf>
    https://brainmass.com/chemistry/acids-and-bases/working-molarity-molality-ph-15858

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