Based on the graph, we would expect the bacterial population to change over time. Initially, growth is exponential. The population curve then levels off; that probably represents the carrying capacity for the population. The curve then turns downward indicating a decline in the microbial population. The decline can be attributed to many factors, both density-dependent and density-independent.
You would still have 651 g of a certain compound but in different products, so the splitting of water via electrolysis you still have 2 Hydrogen and 1 Oxygen.
