Calculate the % yeild of the reaction if 64 g of NaBH4 with iodine produces 15_g of BI3

To calculate the percent yield of a reaction, you need to compare the actual yield (the amount of product obtained experimentally) with the theoretical yield (the maximum amount of product that can be obtained based on stoichiometry).

First, we need to determine the balanced equation for the reaction between sodium borohydride (NaBH4) and iodine (I2) to form boron triiodide (BI3).

The balanced equation is:

3 NaBH4 + 4 I2 -> BI3 + 6 H2 + 12 NaI

From the balanced equation, we can see that the molar ratio between NaBH4 and BI3 is 3:1. This means that for every 3 moles of NaBH4, 1 mole of BI3 is produced.

To calculate the theoretical yield of BI3, we need to convert the given mass of NaBH4 to moles, then use the molar ratio to convert to moles of BI3, and finally convert back to grams.

1. Calculate the moles of NaBH4:
molar mass of NaBH4 = 22.99 g/mol (Na) + 10.81 g/mol (B) + 4 * 1.01 g/mol (H) = 37.83 g/mol
moles of NaBH4 = mass / molar mass = 64 g / 37.83 g/mol = 1.691 moles

2. Calculate the moles of BI3 using the molar ratio:
moles of BI3 = moles of NaBH4 / 3 = 1.691 moles / 3 = 0.564 moles

3. Calculate the theoretical yield of BI3:
molar mass of BI3 = 10.81 g/mol (B) + 3 * 126.90 g/mol (I) = 391.41 g/mol
theoretical yield of BI3 = moles of BI3 * molar mass = 0.564 moles * 391.41 g/mol = 220.77 g

Now, we can calculate the percent yield using the actual yield and the theoretical yield:

percent yield = (actual yield / theoretical yield) * 100
percent yield = (15 g / 220.77 g) * 100 = 6.8%

Therefore, the percent yield of the reaction is approximately 6.8%.