A student prepared a cereal sample solution using a procedure similar to that in Lab 5. The original sample solution was diluted by a factor of two, and then the absorbance of the diluted sample solution was measured and recorded as (4.0x10^-1). Use the following calibration plot and the dilution factor to determine the concentration of iron, in unit of M, in the original cereal sample solution. The trendline (linear regression) as displayed on the plot is y = 11898x - 0.0112.
Question
A student prepared a cereal sample solution using a procedure similar to that in Lab 5. The original sample solution was diluted by a factor of two, and then the absorbance of the diluted sample solution was measured and recorded as (4.0x10^-1). Use the following calibration plot and the dilution factor to determine the concentration of iron, in unit of M, in the original cereal sample solution. The trendline (linear regression) as displayed on the plot is y = 11898x - 0.0112.
Solution
To determine the concentration of iron in the original cereal sample solution, we need to follow these steps:
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First, we need to use the absorbance value and the equation of the trendline to find the concentration of the diluted sample. The equation of the trendline is y = 11898x - 0.0112, where y is the absorbance and x is the concentration. We can rearrange this equation to solve for x (concentration): x = (y + 0.0112) / 11898.
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Substitute the given absorbance value (4.0x10^-1) into the equation: x = (4.0x10^-1 + 0.0112) / 11898.
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Solve the equation to find the concentration of the diluted sample.
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Since the original sample solution was diluted by a factor of two, the concentration of the original sample is twice the concentration of the diluted sample. So, multiply the concentration of the diluted sample by 2 to find the concentration of the original sample.
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The result is the concentration of iron in the original cereal sample solution, in unit of M (molarity).
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