Answer:
(a)
(b) 15 hours
Explanation:
half life, T = 12 hours
No = 19 g
(a) Let N be the amount remaining after time t.
Let λ be the decay constant.
The equation of radioactivity used here is given by
(b) N = 8 gram
Substitute the values in above equation
λ = 0.0577 per hour
So,
Take natural log on both the sides
- 0.0577 t = - 0.865
t = 15 hours
The mass percent composition of aluminum is 52.9% in aluminum oxide.
Mass of the aluminum = 3.53 g
Mass of the aluminum oxide = 6.67 g.
The mass percent of a substance is the mass of the substance divided by the mass of the compound into 100.
Aluminum reacts with oxygen to form aluminum oxide.
The overall balanced equation for the reaction is,
The mass percent composition of aluminum in the aluminum oxide is,
= 52.9 %
Therefore, the mass percent composition of aluminum is 52.9% in aluminum oxide.
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