A 0.682g sample of impure NAHco3 yielded a solid residue consisting of NAc03 and other solid with a mass of 0.467g. What was the mass percent of NAc03 in the sample.
The right 85.4%
Who help
You have many typos in the problem. Here is the solution with the typos corrected.
Let x = mass NaHCO3
and y = mass of the impurity.
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x + y = 0.682
x(molar mass Na2CO3/2*molar mass NaHCO3) + y = 0.467
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The above two equations in two unknowns; solve for x = mass NaHCO3.
Then %NaHCO3 = (x/0.682)*100 = 85.4%
Note: I suppose the problem assumes that the impurity is not changed by heating; otherwise it can't be worked.
To find the mass percent of NAc03 in the sample, you need to first calculate the mass of NAc03 in the solid residue and then divide it by the mass of the original sample.
1. Start by subtracting the mass of the solid residue from the mass of the impure sample to find the mass of NAc03:
Mass of NAc03 = Mass of impure sample - Mass of solid residue
= 0.682g - 0.467g
= 0.215g
2. Now, divide the mass of NAc03 by the mass of the original sample and multiply by 100 to get the mass percent:
Mass percent of NAc03 = (Mass of NAc03 / Mass of impure sample) x 100
= (0.215g / 0.682g) x 100
= 0.315 x 100
= 31.5%
Therefore, the mass percent of NAc03 in the sample is 31.5%.
The previous answer of 85.4% was incorrect. It may have been a mistake or an error in calculation. Always double-check your work to avoid such errors.