Answer:
B. 0.5 molar
Explanation:
Given data:
Initial concentration = 0.40 M
Initial volume = 750 mL
Final volume =750 - 150 mL = 600 mL
Final concentration = ?
Solution:
Molarity is the number of moles of solutes in litter of solvent. In given problem it is stated that when the solution is uncovered solvent evaporate it means molarity is changed. we can calculate the new molarity with the following formula.
C₁V₁ = C₂V₂
C₁ = initial concentration
V₁ = initial volume
C₂ = final concentration
V₂ = final volume
Now we will put the values in formula.
C₁V₁ = C₂V₂
0.40 M × 750 mL = C₂ × 600 mL
300 M.mL / 600 mL = C₂
0.5 M = C₂
I’m not sure it’s correct but I think it’s D) He used voltage adjustments to make charges oil drops float
