Home > Community > What is the theoretical yield of rhodium(III) hydroxide from the reaction of 0.540 g of rhodium (III) sulfate with 0.209 g of sodium hydroxide? Equation: RH2(SO4) 3 + 6NaOH -> 2Rh(OH) 3 + 3Na2SO4.
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+ Chemical reactions
+ Hydroxides
+ Sodium hydroxide
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+ Stoichiometry
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Mike Eisler

What is the theoretical yield of rhodium(III) hydroxide from the reaction of 0.540 g of rhodium (III) sulfate with 0.209 g of sodium hydroxide? Equation: RH2(SO4) 3 + 6NaOH -> 2Rh(OH) 3 + 3Na2SO4.

Brian Dean  Follow

In this question you are given an experimental mass of both of the reactants. We have to determine which reactant is limiting (will be all used up) because this reactant will determine how much product we can produce.

First start by determining the number of moles of each reactant that is being used in this experiment:

n(Rh2(SO4)3) = m/M = 0.540 g/493.999 g/mol = 0.001093 mol Rh2(SO4)3

n(NaOH) = m/M = 0.209 g/39.997 g/mol = 0.005225 mol NaOH

To determine which reactant is limiting, we must compare the experimental mole ratio to the ideal ratio defined by the balanced chemical equation:

Ideal Ratio for NaOH/Rh2(SO4)3 = 6 mol/1mol

Exp. Ratio for NaOH/Rh2(SO4)3 = 0.005225 mol/0.001093 mol = 4.78 mol/1 mol

This tells us that there is not enough NaOH to consume all of the Rh2(SO4)3. The NaOH is the limiting reactant (the reaction will stop when the NaOH is all used up).

The number of moles of Rh(OH)3 that should be produced can be predicted by assuming that all of the NaOH is converted to product and using the mole ratio from the balanced chemical equation:

n(Rh(OH)3) = 0.005225 mol NaOH x (2 mol Rh(OH)3/6 mol NaOH) = 0.001742 mol Rh(OH)3 produced

We can now convert moles of Rh(OH)3 to mass using its molar mass:

m(Rh(OH)3) = n • M = 0.001742 mol (153.98 g/mol) = 0.268 g Rh(OH)3

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Asela Giganage  Follow

molRH2(SO4) 3=0.54gr/(206+3*32+12*16gr.mol^-1)=0.0011 excess reactant

molNaOH=0.209gr/40gr.mol^-1/6=8.7*10^-4 limiting reactant

grtheoretical yield of rhodium(III) hydroxide=8.7*10^-4 *2*(103+48+3gr.mol^-1)=0.2682gr

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