The human body obtains 885 kJ of energy from a chocolate chip cookie.
If this energy were used to vaporize at 100 degree Celsius, how many grams of water could be vaporized? The heat of vaporization of water at 100 degrees Celsius is 40.7 kJ/mole.
40.7 kJ/mol x #mols H2O = 885 kJ
Solve for #mols H2O and convert to grams. g = mols x molar mass
To answer this question, we need to use the concept of heat of vaporization and the given information about energy obtained from the chocolate chip cookie.
First, let's convert the energy obtained from the cookie to joules. We are told that the human body obtains 885 kJ of energy from the cookie. 1 kJ is equal to 1000 J, so the energy obtained is 885,000 J.
Next, we need to determine the number of moles of water that can be vaporized using this energy. We can use the heat of vaporization of water at 100°C, which is 40.7 kJ/mole.
To calculate the number of moles, we can use the formula:
moles = energy (J) / heat of vaporization (J/mole)
moles = 885,000 J / 40,700 J/mole
Calculating this, we find:
moles ≈ 21.7 moles
Finally, we can use the molar mass of water to calculate the mass of water vaporized. The molar mass of water is approximately 18 g/mole.
mass = moles × molar mass
mass = 21.7 moles × 18 g/mole
Calculating this, we find:
mass ≈ 391.5 g
Therefore, approximately 391.5 grams of water could be vaporized using the energy obtained from the chocolate chip cookie.