A 7.50 g sample of potassium-40 was collected. After 8.757 x 10^9 years,
0.05859 g of the sample remained. What is the half-life of potassium-40?

answer : a model is often used to explain and make things easier to understand when any scientific topic needs to be demonstrated and explained.

as in this case where a scientist wants to use a model to present the results of his detailed scientific investigation. he should do it as it will him to make the audience understand the concept in a much better way. also, it can be changed according to new scientific understandings.

your answer is a. the enthalpy of formation for a pure element in its standard state is always positive.

what is the average time it took the car to travel 0.25 meters?

⇒ 2.23 seconds

what is the average time it took the car to travel 0.50 meters?

⇒ 3.13 seconds