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A 75.0 mL aliquot of a 1.60 M solution is diluted to a total volume of 258 mL. A 129 mL portion of that solution is diluted by adding 125 mL of water. What is the final concentration? Assume the volumes are additive.

Respuesta :

Answer: Thus the final concentration is 0.236 M

Explanation:

According to moalrity equation:

[tex]M_1V_1=M_2V_2[/tex]

[tex]M_1[/tex] = Molarity of stock solution = 1.60 M

[tex]V_1[/tex] = volume of stock solution = 75.0 ml

[tex]M_2[/tex] = molaity of diluted solution = ?

[tex]V_2[/tex] = volume of diluted solution = 258 ml

[tex]1.60\times 75.0=M_2\times 258[/tex]

[tex]M_2=0.465M[/tex]

For second dilution:

[tex]M_1V_1=M_2V_2[/tex]

[tex]M_1[/tex] = Molarity of stock solution = 0.465 M

[tex]V_1[/tex] = volume of stock solution = 129 ml

[tex]M_2[/tex] = molaity of diluted solution = ?

[tex]V_2[/tex] = volume of diluted solution = (129+125) = 254 ml

[tex]0.465\times 129=M_2\times 254[/tex]

[tex]M_2=0.236M[/tex]

Thus the final concentration is 0.236 M

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