What the answer I’m on a midterm and can’t seem to find it help
1 answer:
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Answer:
Explanation:
When heat is supplied to a substance, the temperature of the substance increases according to:
where
Q is the amount of heat supplied
m is the mass of the substance
C is the specific heat capacity of the substance
is the initial temperature
is the final temperature
For the sample of magnesium in this problem, we have:
m = 63 g is the mass
Q = 6689 J is the hear supplied
C = 1.023 J/gC is the specific heat capacity
is the final temperature
Solving the formula for , we find the final temperature:
Answer:
Explanation:
A radioactive isotope is an isotope that undergoes nuclear decay, breaking apart into a smaller nucleus and emitting radiation during the process.
The half-life of an isotope is the amount of time it takes for a certain quantity of a radioactive isotope to halve.
For a radioactive isotope, the amount of substance left after a certain time t is:
(1)
where
is the mass of the substance at time t = 0
m(t) is the mass of the substance at time t
is the half-life of the isotope
In this problem, the isotope is uranium-235, which has a half-life of
We also know that the amount of uranium left in the rock sample is 6.25% of its original value, this means that
Substituting into (1) and solving for t, we can find how much time has passed: