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Do not use any other values except the ones provided in the table below.

Element Molar Mass (g/mol)

Carbon 12.01

Hydrogen 1.01

oxygen 16.00

1.
Correctly calculate the molar mass of Ethanol (CHsmall3CHsmall2OH) and type the value below.

2.
A chemist will use a sample of 30g of glucose (Csmall6Hsmall12Osmall6) in an experiment. Determine the number of moles of glucose the chemist will use based on the molar mass values provided in the table.

Your answers should be a number with 2 decimal places; i.e. the hundredths place.

1 answer

  1. To calculate the molar mass of Ethanol (C₂H₅OH), we can sum the molar masses of the individual elements:
  • Carbon (C): 2 × 12.01 g/mol = 24.02 g/mol
  • Hydrogen (H): 6 × 1.01 g/mol = 6.06 g/mol
  • Oxygen (O): 1 × 16.00 g/mol = 16.00 g/mol

Now add them together: \[ \text{Molar Mass of Ethanol} = 24.02 , \text{g/mol} + 6.06 , \text{g/mol} + 16.00 , \text{g/mol} = 46.08 , \text{g/mol} \]

Thus, the molar mass of Ethanol is 46.08 g/mol.

  1. To find the number of moles of glucose (C₆H₁₂O₆) in a 30 g sample, we first calculate the molar mass of glucose:
  • Carbon (C): 6 × 12.01 g/mol = 72.06 g/mol
  • Hydrogen (H): 12 × 1.01 g/mol = 12.12 g/mol
  • Oxygen (O): 6 × 16.00 g/mol = 96.00 g/mol

Now add them together: \[ \text{Molar Mass of Glucose} = 72.06 , \text{g/mol} + 12.12 , \text{g/mol} + 96.00 , \text{g/mol} = 180.18 , \text{g/mol} \]

Now we can determine the number of moles of glucose in 30 g: \[ \text{Number of moles} = \frac{\text{mass (g)}}{\text{molar mass (g/mol)}} = \frac{30 , \text{g}}{180.18 , \text{g/mol}} \approx 0.1665 \]

Rounding this to two decimal places gives us 0.17 moles.