Answer:
[Sr(OH)₂] = 0.699 M in Sr(OH)₂ sol'n (1 sig. fig)
Step-by-step explanation:
Concentrated-1 Sr(OH)₂ = M₁ = unknown Concentration-2 HCl = M₂ = 0.350M
Volume of Concentrate = V₁ = 15ml Volume of Diluted = V₂ = 29.8ml
Using the Dilution Equation
Molarity x Volume of Concnt'd Soln = Molarity x Volume of Diluted Soln
From definition of molarity (M) = moles solute / volume of solution in Liters
=> moles solute = Molarity x Volume in liters*
*Note: if volume units are the same on both sides of the dilution equation then one may retain the volume in ml.
M₁ x V₁ = M₂ x V₂
=> 15ml · [Sr(OH)₂] = 30ml X 0.350M HCl soln
=> [Sr(OH)₂] = 29.8ml X 0.350M / 15ml = 0.695333... (calculator answer)
=> [Sr(OH)₂] = 0.7 M in Sr(OH)₂ sol'n (1 sig. fig)
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work check:
M₁ x V₁ = M₂ x V₂
0.6953M x 15ml = 0.35M x 29.8ml
10.43 moles = 10.43 moles QED