Question

Butyric acid has a density of 0.959 g/mL at 20°C. How many moles of butyric acid are contained in 1.56 mL of butyric acid Expresp your answer to three significant figures and include the appropriate units.

Answer 1

To find the number of moles of butyric acid, we need to use the formula:

moles = mass / molar mass

First, we need to find the mass of butyric acid in 1.56 mL. We can do this by multiplying the volume (1.56 mL) by the density (0.959 g/mL):

mass = volume * density
mass = 1.56 mL * 0.959 g/mL
mass = 1.49504 g

Next, we need to calculate the molar mass of butyric acid. The molecular formula of butyric acid is C₄H₈O₂. To calculate the molar mass, we can sum the atomic masses of each element in the formula:

molar mass = (4 * atomic mass of carbon) + (8 * atomic mass of hydrogen) + (2 * atomic mass of oxygen)
molar mass = (4 * 12.01 g/mol) + (8 * 1.008 g/mol) + (2 * 16.00 g/mol)
molar mass = 88.11 g/mol

Now we can determine the number of moles of butyric acid by dividing the mass (1.49504 g) by the molar mass (88.11 g/mol):

moles = mass / molar mass
moles = 1.49504 g / 88.11 g/mol
moles = 0.01695 mol

Therefore, there are 0.017 mol of butyric acid in 1.56 mL.