Question

How many moles are in a sample of ethylene glycol (commonly found in antifreeze), HOCH₂CH₂OH, that has a volume of 250.0 mL? The molar mass and density of ethylene glycol are 62.07g/mol and 1.11g/mL respectively.

a) 2.25 moles
b) 4.01 moles
c) 1.50 moles
d) 3.76 moles

Answer 1

To calculate the moles of ethylene glycol in a 250.0 mL sample, we use its density (1.11 g/mL) to find its mass (277.5 g) and then divide by its molar mass (62.07 g/mol) to obtain approximately 4.47 moles. This value does not match any of the provided choices, suggesting an error in the question.

Step-by-step explanation:

To calculate the number of moles of ethylene glycol in a 250.0 mL sample, we will first convert the volume of ethylene glycol to mass using its density, and then convert the mass to moles using the molar mass:

• Determine the mass using the density:
  Density of ethylene glycol = 1.11 g/mL
  Volume of ethylene glycol = 250.0 mL
  Mass = Density × Volume = 1.11 g/mL × 250.0 mL = 277.5 g
• Convert the mass to moles using the molar mass:
  Molar mass of ethylene glycol = 62.07 g/mol
  Moles of ethylene glycol = Mass / Molar mass = 277.5 g / 62.07 g/mol ≈ 4.47 moles

Thus, the sample of ethylene glycol contains approximately 4.47 moles, which is not an option listed above. It seems there might be an error in the question as presented, since none of the options given match the calculated value. Therefore, we cannot confidently select any of the options (a) through (d).