The time needed for a substance becomes half of it mass is called half-time, after. In this case, the half time is 100 minutes. Then to know how much substance remain after 200 minutes the equation would be:
Substance remains= 1/2^(time/half-time) x substance initial mass
Substance remains = 1/2^(200 minutes/100minutes) x 1 times= 1/4 times
You should get 5.05 x 10^23 moles.
<u>Answer: </u>
Phases of moon:
- New Moon
- crescent Moon
- First-quarter Moon
- gibbous Moon
- full Moon
<u>Explanation:</u>
The lunar cycle has 8 phases. The first phase is new moon. New moon is seen while the moon lies between the sun and the earth. After few days occurs the crescent moon when the moon travels towards its east. The next phase is first-quarter phase. During this phase half of the moon will be illuminated. The fourth phase is waxing gibbous moon phase where waxing refers to 'growing larger' and gibbous means 'shape' hence waxing gibbous refers to growing shape. Next is the full moon phase. This happens when the moon and the sun comes on the opposite sides of our earth. The next phase will be waning gibbous moon where the moon decreases in size. This phase is followed by third quarter and finally the waning crescent moon phase.
2Na^+ and S^2-
(sodium cation and sulfide anion)
