can you help me with this
The half-life of technetium-99m is 6.0 hours. A 120 .- mg sample of technetium-99m is used for a diagnostic procedure.
Part 1 of 2
How much Tc-99m remains after 12.0 hours? Be sure your answer has the correct number of significant figures.
mg of Tc-99m
Part 2 of 2
How much Tc-99m remains after exactly 3 days? Be sure your answer has the correct number of significant figures.
mg of Tc-99m
Part 1:
After 12 hours, the amount of technetium-99m remaining can be calculated using the formula: A = A₀ * (1/2)^(t/t₁/₂), where A is the remaining amount, A₀ is the initial amount, t is the time passed, and t₁/₂ is the half-life.
A = 120 mg * (1/2)^(12/6)
A = 120 mg * (1/2)^2
A = 120 mg * 1/4
A = 30 mg
Therefore, after 12.0 hours, 30 mg of technetium-99m remains.
Part 2:
After 3 days (3 * 24 = 72 hours), we can use the same formula:
A = 120 mg * (1/2)^(72/6)
A = 120 mg * (1/2)^12
A = 120 mg * 1/4096
A = 0.029 mg
Therefore, after exactly 3 days, 0.029 mg of technetium-99m remains.