Question

Given stock solution of glucose (1000mM), asparagine (100mM) and NaH2PO4 (50mM), how much of each solution do you need to prepare 500mL of a reagent that contains 50mM glucose, 10mM of asparagine and 2mM of NaH2PO4.

Answer 1

Answer on Question #57572, Chemistry / General Chemistry

Answer: 25mL stock solution of glucose, 50mL stock solution of asparagine and 20mL stock solution of NaH₂PO₄

Solution:

Molarity = moles solute/ volumes of solution in liters,

or M = n/V

V = 500 mL = 0.5L

M₂ (glucose) = 50mM = 0.05M

M₁ (glucose) = 1000mM = 1M

n (glucose) = M*V = 0.05M * 0.5L = 0.025 mole,

so you need 0.025 mole / 1M = 0.025L (25mL) stock solution of glucose

M₂ (asparagine) = 10mM = 0.01M

M₁ (asparagine) = 100mM = 0.1M

n (asparagine) = M*V = 0.01M * 0.5L = 0.005 mole,

so you need 0.005 mole / 0.1M = 0.05L (50mL) stock solution of asparagine

M₂ (NaH₂PO₄) = 2mM = 0.002M,

M₁ (NaH₂PO₄) = 50mM = 0.05M

n (NaH₂PO₄) = M*V = 0.002M * 0.5L = 0.001 mole,

so you need 0.001 mole / 0.05M = 0.02L (20mL) stock solution of NaH₂PO₄

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