In the substitution reaction of 2-pentanol with sulfuric acid and sodium bromide, how many grams of sodium bromide and mL of sulfuric acid would be required if we use 3.5 grams of 2-pentanol?
To determine the amount of sodium bromide and sulfuric acid required for the substitution reaction of 2-pentanol, we need to understand the stoichiometry of the reaction. The balanced chemical equation for this reaction is:
2-pentanol + HBr -> 2-bromopentane + H2O
From the balanced equation, we can see that one mole of 2-pentanol reacts with one mole of HBr to produce one mole of 2-bromopentane. Additionally, the molar ratio between sodium bromide and HBr is 1:1.
To calculate the required amounts, follow these steps:
Step 1: Convert the mass of 2-pentanol to moles.
Calculate the molar mass of 2-pentanol (C5H12O) by adding up the atomic masses of carbon, hydrogen, and oxygen:
C (12.01 g/mol) x 5 + H (1.01 g/mol) x 12 + O (16.00 g/mol) = 88.17 g/mol
Divide the mass of 2-pentanol by its molar mass to obtain the number of moles:
3.5 g 2-pentanol / 88.17 g/mol = 0.0397 moles 2-pentanol
Step 2: Determine the stoichiometric ratios.
From the balanced equation, we know that:
1 mole of 2-pentanol reacts with 1 mole of HBr and 1 mole of sodium bromide.
Step 3: Calculate the required amount of sodium bromide.
Since the stoichiometric ratio between 2-pentanol and sodium bromide is 1:1, this means we need 0.0397 moles of sodium bromide.
Step 4: Convert moles of sodium bromide to grams.
The molar mass of sodium bromide (NaBr) is:
Na (22.99 g/mol) + Br (79.90 g/mol) = 102.89 g/mol
Multiply the number of moles by the molar mass to find the mass:
0.0397 moles NaBr x 102.89 g/mol = 4.08 grams NaBr (rounded to two decimal places)
Therefore, you would need approximately 4.08 grams of sodium bromide for this reaction.
Step 5: Calculate the required amount of sulfuric acid.
Since the ratio between 2-pentanol and HBr is 1:1, we need the same number of moles of HBr as 2-pentanol, which is 0.0397 moles.
Step 6: Convert moles of sulfuric acid to volume (mL).
First, we need to know the molarity of the sulfuric acid solution.
Assuming the sulfuric acid concentration is 6 M (as a common value), 6 moles of sulfuric acid are present in 1 liter (1000 mL) of solution.
Using the equation:
moles = molarity x volume (in liters),
we can rearrange it to solve for volume:
volume (L) = moles / molarity
Substituting the known values:
volume (L) = 0.0397 moles / 6 M = 0.0066 L
Finally, convert liters to milliliters:
volume (mL) = 0.0066 L x 1000 mL/L = 6.6 mL
Therefore, you would need approximately 6.6 mL of sulfuric acid for this reaction.
In summary, to perform the substitution reaction of 3.5 grams of 2-pentanol, you would need approximately 4.08 grams of sodium bromide and 6.6 mL of sulfuric acid.