Final answer:
To accurately determine the amount of lead-196 remaining, the half-life of the isotope is essential. Without this information, it is impossible to give a precise answer. If we had the half-life, we would apply the concept of radioactive decay to calculate the remaining lead-196.
Step-by-step explanation:
To determine how much lead-196 is left after 74 minutes, we need to know the half-life of lead-196. However, since the half-life of lead-196 is not provided, we need to use a similar example to illustrate the process of decay. For instance, for the isotope titanium-44 which has a half-life of 60 years, the amount left after four half-lives (240 years) would be one sixteenth of the original amount, since each half-life reduces the amount to one half of the previous amount.
By this logic, with enough half-life information, the calculation for the original amount of 4.8 grams of lead-196 after 74 minutes could be approximated. Unfortunately, without the half-life information for lead-196, an accurate answer cannot be determined. As for the examples provided for other isotopes, the remaining amount of a radioactive isotope can be calculated using its half-life and the amount of time that has passed.