Question

Using the balanced equation below,how many grams of sodiumthiosulfate would be required toproduce 64.3 g NaBr?AgBr + 2Na2S2O3 → Na3Ag(S203)2 + NaBr

Answer 1

You can see that in the balanced equation 2 moles of sodium thiosulfate produce 1 mole of NaBr. So first, let's find the number of moles of 64.3 g of NaBr using its molar mass which is 102.9 g/mol:

`64.3\text{ g NaBr}\cdot\frac{1\text{ mol NaBr}}{102.9\text{ g NaBr}}=0.625\text{ mol NaBr.}`

With this value, we can find the number of moles of Na2S2O3 using a rule of three:

`\begin{gathered} \text{2 moles Na}_2S_2O_3\to\text{ 1 mol NaBr} \\ \text{? moles Na}_2S_2O_3\to0.625\text{ mol NaBr} \end{gathered}`

And we're going to obtain:

`0.625\text{ mol NaBr}\cdot\frac{\text{2 moles Na}_2S_2O_3}{1\text{ mol NaBr}}=1.25\text{ moles Na}_2S_2O_3`

And the final step is to do the conversion from moles to grams using the molar mass of sodium thiosulfate which is 158 g/mol:

`1.25\text{ moles Na}_2S_2O_3\cdot\frac{15\text{8.11 g Na}_2S_2O_3}{1\text{ mol Na}_2S_2O_3}=197.63\text{ g Na}_2S_2O_3.`

The answer is that we need 197.6 grams of sodium thiosulfate to produce 64.3 grams of NaBr.