Hey there!
A half-life means after a certain amount of time, half of that substance will be gone/changed after that time.
60 hours is 4 half lives because 60 ÷ 15 = 4.
So, the 18g sample will be divided in half 4 times.
18 ÷ 2 = 9
9 ÷ 2 = 4.5
4.5 ÷ 2 = 2.25
2.25 ÷ 2 = 1.125
There will he 1.125g of sodium-24 left after 60 hours.
Hope this helps!
Answer:
4. KCl(s)
Explanation:
KCl is an ionic salt that dissolves in water to form a KCl aqueous solution.
Answer:
Atoms were impenetrably hard, meaning they could not be divided. In Greek, the prefix "a" means "not" and the word "tomos" means cut. Our word atom therefore comes from atomos, a Greek word meaning uncuttable.
A pendulum. Hold it high and it has potential energy but no kinetic energy because it is still. As it moves down when you drop it, it changes to kinetic energy and moves faster and faster until it's at the bottom where it has no potential energy. However, it still has momentum, so now it is changed to potential energy as it moves up the other side
Groups 13-16, hope this helps!
