Sodium-24 has a half life of 15 hours. how much sodium-24 will remain in an 18.0 g sample after 60 hours

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: c. the experiment shows that the red substance experienced a chemical change.

explanation: chemical change is the change in which chemical composition of the substance changes. physical change is the change in which there is no change in chemical composition.

chemical changes are accompanied by following changes:

a) precipitate formation

b) energy is released or absorbed

c) formation of bubbles

d) change in color

as it is given that the red color has disappeared and there is production of gas, it means the red substance has undergone a chemical change.

e

um i think it might be a car?