8 seconds have passed. There is a sample of lithium-8 being tested. The half-life of lithium-8 is 0.84 seconds. The sample of lithium-8 after 8 seconds is 28 grams. How much lithium-8 was in the sample at the beginning of the experiment? Round your answer to 2 sig figs.
Do no forget units!

Why are people not able to scuba dive in the deep part of the ocean

Which of the following two events occur to create a sea breeze? select all that apply. warm air rises on the ocean and moves toward the land to cool warm air rises on land and moves toward the ocean to cool cool air moves from the ocean to be warmed by the land cool air moves from the land to be warmed by the ocean

If 1.8 l of water is added to 2.5l of a 7.0 m koh solution, what is the molarity of the new solution