I am confused about how to claculate half lives. Can you explain. ( How much of a 400 gm sample od gold is left after 10.8 days if the half life is 2.7)
This way.
k = 0.693/t1/2
You don't have any units for the half life of 2.7 WHAT? Make sure unit for this agrees with unit below (in days).
Substitute k into the equation below.
ln(No/N) = kt
No = what you start with--400 g
solve for N, the number left after time t.
k from above.
t = time = 10.8 days.
2.7 days.. so the answer is 25 g ?
1. billion
I don't know the answer to your question, but can some one help me with mine?
Question: After six half-lives, what percentage of a radioactive sample will remain?
Please help me!, Thank you.
Responding to Amber,
Six half lives:
1/2 * 1/2 * 1/2 * 1/2 * 1/2 * 1/2 = 1/64 = 0.015625 = 1.5625%
Sure! I can explain how to calculate half-lives and help you solve the specific problem you mentioned.
The half-life of a substance is defined as the amount of time it takes for half of a given quantity of that substance to decay or transform into another form. It is a characteristic property of a radioactive element or a process that undergoes exponential decay.
To calculate the remaining amount of a substance after a certain number of half-lives, you can use the following formula:
Remaining amount = Initial amount × (1/2)^(number of half-lives)
In your case, let's break down the problem:
1. Initial amount: You have a 400 gm sample of gold.
2. Half-life: The half-life of gold is given as 2.7 days.
3. Time passed: The time passed is given as 10.8 days.
To find the number of half-lives (n) that have passed, divide the time passed by the half-life:
n = Time passed / Half-life
n = 10.8 days / 2.7 days
n = 4
Now that you know the number of half-lives (n), you can calculate the remaining amount using the formula mentioned earlier:
Remaining amount = Initial amount × (1/2)^(number of half-lives)
Remaining amount = 400 gm × (1/2)^4
Remaining amount = 400 gm × (1/16)
Remaining amount = 25 gm
After 10.8 days, there will be 25 grams of gold remaining from the initial 400 grams sample.
I hope this explanation helps! Let me know if you have any further questions.