0.5 mg
.25 mg
1 mg
0.25 mg
0.5 mg
This would depend on the specific sample and its stability. Without additional information, it is not possible to determine how much of the sample would remain unchanged after two hours.
5g would remain
1mg
0.5 mg
The mass is 1,075 g.
The mass is 1,075 g.
I suppose that you think to the radioactive isotope Cs-17; After 4 years remain 9,122 g.
You must know the half life of Caesium to calculate this.
0.25
1 mg
Approximately 400 grams of the potassium-40 sample will remain after 3.91 years, as potassium-40 has a half-life of around 1.25 billion years. This means that half of the initial sample would have decayed by that time.
.25 mg