Answer:
Step-by-step explanation:
We need to find the molar mass of NaBr to convert the given mass to moles and then use the stoichiometric coefficients to calculate the moles of Na2S2O3 required to produce that amount of NaBr. Finally, we can use the molar mass of Na2S2O3 to convert the moles to grams.
The molar mass of NaBr is 102.89 g/mol (22.99 g/mol for Na + 79.90 g/mol for Br). Therefore, the number of moles of NaBr is:
64.3 g / 102.89 g/mol = 0.625 moles NaBr
According to the balanced equation, 1 mole of AgBr reacts with 2 moles of Na2S2O3 to produce 1 mole of NaBr. Therefore, the number of moles of Na2S2O3 required is:
0.625 moles NaBr x (2 moles Na2S2O3 / 1 mole NaBr) = 1.25 moles Na2S2O3
Finally, we can convert the moles of Na2S2O3 to grams using its molar mass:
1.25 moles Na2S2O3 x 158.11 g/mol = 197.64 g Na2S2O3
Therefore, 197.64 grams of Na2S2O3 would be required to produce 64.3 g of NaBr.