Answer:
5.61 * 10²¹ molecules
Explanation:
You have 1.25 g of malic acid, C4H.Os, an acid found in apples and other fruits. How many molecules of the acid do you have?
Solution:
A molecule is the group of two or more atoms held together by chemical bonds.
The number of molecules is calculated using the formula:
number of molecules in a substance = number of moles of substance * Avogadro constant
Avogadro constant = 6.02 * 10²³ mol⁻¹
number of moles = mass / molar mass
Given that mass = 1.25 g
molar mass of malic acid (C₄H₆O₅) = (12 * 4) + (1 * 6) + (16 * 5) = 48 + 6 + 80 = 134 g/mol
number of moles = mass / molar mass = 1.25 g / 134 g/mol = 0.0093 mol
Recall that: number of molecules in a substance = number of moles of substance * Avogadro constant
number of molecules in a substance = 0.0093 mol * 6.02 * 10²³ mol⁻¹ = 5.61 * 10²¹ molecules
