1000 is the answer to the queshtion
I believe the correct answer from the choices listed above is option 2. The isotope of an atom that contains 40 protons and 51 neutrons and suddenly has two neutrons added to it would be Zirconium-93. We look at a periodic table and find the element with the atomic number 40 which equal the number of protons.
The water pollution comes from trash
Answer:
years.
Explanation:
The half-life is the time needed to reduce in 50% the mass of the sample. So, imagine compound A, after its first half-life, it will have 0.5A. After its second half-life, will have 50% of the 0.5A! So, the mass will be 0.25A. So, the percentage of A, is given by:

Where n is the quantitative of half-life. So, for 18.7% of C, or 0.187:

Applying log in both side of the equation:

nlog(0.5) = log(0.187)
-0.301n = -0.728
n = 2.419 half-life
If one half-life is 5,730 yr, than 2.419 will be:
2.419x5730 = 13,860.870 yr
years.
CuSO4. 5H2O(s) → CuSO4(s) + 5 H2O(g)
Here, when we heat copper (II) sulphate pentahydrate, it will turn white in colour from blue colour.