an element with mass 630 grams decays by 18.8% per minute. how much of the element is remaining after 7…

Explanation:

Step1: Identify decay formula

The formula for exponential - decay is $A = A_0(1 - r)^t$, where $A_0$ is the initial amount, $r$ is the rate of decay, and $t$ is the time. Here, $A_0=630$ grams, $r = 0.188$, and $t = 7$ minutes.

Step2: Substitute values into formula

$A=630\times(1 - 0.188)^7$. First, calculate $1 - 0.188=0.812$. Then, find $(0.812)^7$. $(0.812)^7=0.812\times0.812\times0.812\times0.812\times0.812\times0.812\times0.812\approx0.2177$.

Step3: Calculate the remaining amount

$A = 630\times0.2177\approx136.1$.

Answer:

$136.1$ grams