Answer:
0.15 L= 150 ml
Explanation:
barium choride = BaCl₂
0.51 M = 0.51 mol BaCl₂/ 1 L solution
1 mol is equal to 1000 times a mmol:
0.51 mol = 0.51 x 10³ mmol= 510 mmol
As you know that the solution has 510 mmol BaCl₂ per liter, you can use the following simple calculation to obtain the volume in which there are 75 mmol BaCl₂:
510 mmol BaCl₂ ------ 1 L
75 mmol BaCl₂--------- X
X= = 0.147 L ≈ 0.15 L