Final answer:
To calculate how much of the element is remaining after 18 minutes, we can use the formula: Amount Remaining = Initial Amount * (1 - Decay Rate)^(Time/Time Constant). In this case, the initial amount is 820 grams, the decay rate is 26.8% per minute, and the time constant is the reciprocal of the decay rate (1/26.8%). Substituting these values into the formula, we find that approximately 303.9 grams of the element is remaining after 18 minutes.
Step-by-step explanation:
To calculate how much of the element is remaining after 18 minutes, we can use the formula:
In this case, the initial amount is 820 grams, the decay rate is 26.8% per minute, and the time constant is the reciprocal of the decay rate (1/26.8%). Substituting these values into the formula, we get:
Amount Remaining = 820 * (1 - 0.268)^(18/(1/26.8%))
Calculating this expression, we find that approximately 303.0 grams of the element is remaining after 18 minutes.