We’re being asked to calculate the percent by mass (mass %) of Cr in a 5.60 g steel.
The formula for mass or weight percent is:
We must first find the mass of Cr in the 250.0 mL solution. The flow for this problem will be like this:
Mass of BaCrO4(molar mass of BaCrO4)→ Moles of BaCrO4(mole-to-mole comparison)→ Moles of Cr (molar mass of Cr)→ Mass of Cr in 10.0 mL portion (volume ratio) → Mass of Cr in 250.0 mL solution → Calculate for mass % Cr in steel
A stainless steel alloy is to be analyzed for its chromium content. A 5.60g sample of the steel is used to produce 250.0 mL of a solution containing Cr2O72-? A 10.0-mL portion of this solution is added to BaCl2(aq). When the pH of the solution is properly adjusted, 0.145 g BaCrO 4(s) precipitates.
What is the percent Cr, by mass, in the steel sample?
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