Answer:
3 years
Explanation:
Given data:
Initial amount of sample = 160 Kg
Amount left after 12 years = 10 Kg
Half life = ?
Solution:
at time zero = 160 Kg
1st half life = 160/2 = 80 kg
2nd half life = 80/2 = 40 kg
3rd half life = 40 / 2 = 20 kg
4th half life = 20 / 2 = 10 kg
Half life:
HL = elapsed time / half life
12 years / 4 = 3 years
Using a stove to heat up water.
Answer: 714 g Al2O3
Explanation: Solution attached
First convert mass of O2 to moles
Do the mole ratio between O2 and Al2O3 from the balanced equation.
Convert moles of Al2O3 to mass using its molar mass.