Via half-life equation we have:

Where the initial amount is 50 grams, half-life is 4 minutes, and time elapsed is 12 minutes. By plugging those values in we get:

There is 6.25 grams left of Ra-229 after 12 minutes.
Answer:
a) W=12166.20876 J
b) U= -12166.20876 J
Explanation:
No. of moles, n = 8.41
Change of temperature, ΔT = T1 - T2
= 395 - 279
= 116 K
For monatomic gas, γ = 5/3
γ -1 = 2 /3
Solution:
(a)
Work done,
plugging values we get

Ans:
12166.20876 J
Work done, W = + 12166.20876 J
(b)
From first law of thermodynamics, dQ = U + W
but, dQ = 0
( adiabatic process)
Hence, U = - W
= - 12166.20876 J
Ans:
Change in internal energy, U = - 12166.20876 J
Answer:
6 m/s.
Explanation:
From the question given above, the following data were obtained:
Initial velocity (u) = 4 m/s
Acceleration (a) = 2 m/s²
Distance (s) = 5 m
Final velocity (v) =?
The final velocity of the object can obtained as shown below:
v² = u² + 2as
v² = 4² + (2 × 2 × 5)
v² = 16 + 20
v² = 36
Take the square root of both side.
v = √36
v = 6 m/s
Therefore, the final speed of the object is 6 m/s.
1) -76.27
2)-119.47
3)-256.27
4)-87.07
Here’s the formula for the last one so you know how to do it. Hope this helps!!!
Answer:
Something that relates to the periodic table