Answer: The molar mass of H2S is greater than the molar mass of NH3, making the velocity and effusion rate of NH3 particles faster.
Effusion rate is inversely proportional to molar mass.
NH3 will have a higher average molecule velocity, so it will diffuse faster and will reach the other side of the room more quickly.
Explanation: change up your response a bit
In a flashlight, the electrical energy becomes light energy and thermal energy in the bulb.
Molar mass Na2CO3 = 106 g/mole
Using dimensional analysis:
0.787 moles Na2CO3 x 106 g/mole Na2CO3 = g Na2CO3
Answer = 83.4 g Na2CO3