Final answer:
To make 2.0 moles of urea, 68.12 grams of ammonia is required, based on the balanced chemical equation, where 2 moles of ammonia are needed per mole of urea.
Step-by-step explanation:
The student has asked to write a balanced equation for the combination of carbon dioxide (CO2) and ammonia (NH3) to form urea (CH4N2O) and water, and then calculate the mass of ammonia needed to make 2.0 moles of urea. The balanced chemical equation for the formation of urea from CO2 and NH3 is:
1 CO2(g) + 2 NH3(g) → 1 CH4N2O(s) + 1 H2O(l)
To calculate the mass of ammonia required, we use the molar mass of ammonia (NH3) which is 17.03 g/mol. Since the equation shows that 2 moles of ammonia are needed to produce 1 mole of urea, we need 2 moles of ammonia for every mole of urea produced. For 2 moles of urea, we need:
2 moles of urea × (2 moles of NH3 / 1 mole of urea) × 17.03 g/mol = 68.12 grams of NH3
Therefore, to make 2.0 moles of urea, 68.12 grams of ammonia is required.