Consider the reduction of 4-t-butylcyclohexanone.
If the procedure calls for 153 mg of 4-t-butylcyclohexanone, what mass of sodium borohydride should be added?
To determine the mass of sodium borohydride needed for the reduction of 4-t-butylcyclohexanone, you need to consider the balanced chemical equation and the stoichiometry of the reaction.
The balanced chemical equation for the reduction of 4-t-butylcyclohexanone using sodium borohydride (NaBH4) is:
4-t-butylcyclohexanone + NaBH4 --> 4-t-butylcyclohexanol + NaBO2
From the balanced equation, we can see that the molar ratio between 4-t-butylcyclohexanone and NaBH4 is 1:1. This means that for every 1 mole of 4-t-butylcyclohexanone, we need 1 mole of NaBH4.
Now, let's calculate the molar mass of 4-t-butylcyclohexanone. The molar mass for each element can be found in the periodic table:
C (carbon) = 12.01 g/mol
H (hydrogen) = 1.01 g/mol
O (oxygen) = 16.00 g/mol
Adding up the molar masses of each atom in 4-t-butylcyclohexanone:
(12.01 g/mol x 14) + (1.01 g/mol x 22) + (16.00 g/mol x 1) = 182.28 g/mol
Now, we can calculate the number of moles of 4-t-butylcyclohexanone:
Number of moles = Mass / Molar mass
Number of moles = 153 mg / 182.28 g/mol
= 0.8407 mmol
Since the molar ratio between 4-t-butylcyclohexanone and NaBH4 is 1:1, we need the same number of moles of NaBH4. Therefore, 0.8407 mmol of NaBH4 is required.
Finally, let's calculate the mass of sodium borohydride needed:
Mass = Number of moles x Molar mass
Mass = 0.8407 mmol x (22.99 g/mol + 1.01 g/mol + 4.00 g/mol + 1.007 g/mol)
Mass = 0.8407 mmol x 29.007 g/mol
Mass = 24.42 mg
So, to reduce 153 mg of 4-t-butylcyclohexanone, you would need approximately 24.42 mg of sodium borohydride.