Answer :
Final answer:
The number of moles in 172 grams of pentanal is calculated by dividing the mass of pentanal by its molar mass, which is 176.124 g/mol. The result is approximately 0.9765 moles of pentanal.
Explanation:
To calculate the number of moles in 172 grams of pentanal, we begin by understanding the concept of molar mass.
The molar mass of a compound is the mass in grams of one mole of that compound. For pentanal, the molar mass is 176.124 g/mol.
The number of moles (n) can be found by dividing the mass of the compound in grams (m) by its molar mass (M).
The formula to find the number of moles is:n = m / M
Plugging in the values for pentanal:n = 172 g / 176.124 g/mol
After performing the division, we get approximately 0.9765 moles of pentanal (rounded to four significant figures).
If we consider a very small fraction of a mole, such as 10-4, we expect the corresponding mass to be a tiny fraction of the molar mass.
However, in this case, we have a significant mass (172 g) that corresponds to a substantial number of moles, which is nearly one mole.
This consideration contrasts with an example where a mass close to 0.02 g would correspond to a 10-4 fraction of a mole.
