I can't figure out how to solve this problem, please show how you find the solution:
A sample of 17.0 g of CaCl2 was dissolved in water and made up to the volume in a 250-mL volumetric flask. An 36.00 mL sample of this solution was transferred to another 250-mL volumetric flask and diluted to the mark with water. Determine the concentration (in M) of the final (second) CaCl2 solution.
Chemistry Help??>?
2016-06-15 2:54 am
回答 (2)
2016-06-15 3:06 am
✔ 最佳答案
Mass of CaCl₂ in the final solution = (17.0 g) × (36.00/250)Molar mass of CaCl₂ = (40.08 + 35.45×2) g/mol = 110.98 g/mol
No. of moles of CaCl₂ in the final solution = (17.0 g) × (36.00/250) / (110.98 g/mol)
Molarity of the final solution = [(17.0 g) × (36.00/250) / (110.98 g/mol)] / (250/1000 L) = 0.0882 M
2016-06-15 3:02 am
molar mass CaCl2 ~ 111 g
17.0g X (1mole / 111g) X (1 / 0.250 L ) = molsrity of 1st solution ... use a calculator
... I will use M1 for this answer
M1V1 = M2V2 <<< dilution formula
M1(36.00mL) = M2(250.00mL) <<< solve for M2
M2 = M1 X 36.00 / 250.00 <<< substitute in answer for M1, then use a calculator
... final answer will be M (molarity)
17.0g X (1mole / 111g) X (1 / 0.250 L ) = molsrity of 1st solution ... use a calculator
... I will use M1 for this answer
M1V1 = M2V2 <<< dilution formula
M1(36.00mL) = M2(250.00mL) <<< solve for M2
M2 = M1 X 36.00 / 250.00 <<< substitute in answer for M1, then use a calculator
... final answer will be M (molarity)
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