Final answer:
To determine the total mass of NH3 for a saturated solution in 200 grams of water at 20°C, consult Table G for NH3's solubility at that temperature, then multiply by 2 for the 200 grams of water. The exact mass cannot be provided without Table G.
Step-by-step explanation:
The student's question requires the use of a solubility table (Table G) to determine the mass of NH3 that can be dissolved in 200 grams of water at 20°C to make a saturated solution. Since Table G is not provided here, we cannot provide the exact mass. However, to find the answer, one would look up the solubility of NH3 at 20°C in Table G, which would state the maximum grams of NH3 that can be dissolved in 100 grams of water at that temperature. The student would then use this solubility value to calculate the amount for 200 grams of water. For example, if Table G indicated that 50 grams of NH3 could dissolve in 100 grams of water at 20°C, then for 200 grams of water, the total mass would be 50 grams x 2 = 100 grams of NH3 for a saturated solution.