Answer:
0.0878 moles CaCl₂
Step-by-step explanation:
To find the amount of moles of CaCl₂, you need to
(1) convert the volume from mL to L (1,000 mL = 1 L)
(2) calculate the amount of moles (M = moles / L)
It is important to arrange the conversions in a way that allows for the cancellation of units.
(Step 1)
42 mL CaCl₂ 1 L
------------------------ x ---------------------- = 0.042 L CaCl₂
1,000 mL
(Step 2)
Molarity (M) = moles / volume (L) <----- Molarity ratio
2.09 M = moles / 0.042 L <----- Insert values
0.0878 = moles <----- Multiply both sides by 0.042 L