Answer:
A. Is independent of other energy influences
Explanation:
Nuclear decay occurs at a constant rate. The rate of decay is independent of temperature.
B, C, and D are wrong. The decay rate cannot be sped up or slowed down at ordinary temperatures.
The first statement is true. To remember this, ionic compounds are a mix of the two different types of elements (metal/nonmetal). Electrons are transferred from one atom to the other.
<u>Answer:</u> The original element is ![_{84}^{212}\textrm{Po}](https://tex.z-dn.net/?f=_%7B84%7D%5E%7B212%7D%5Ctextrm%7BPo%7D)
<u>Explanation:</u>
Alpha decay is defined as the process in which alpha particle is emitted. In this process, a heavier nuclei decays into a lighter nuclei. The alpha particle released carries a charge of +2 units.
The released alpha particle is also known as helium nucleus.
![_Z^A\textrm{X}\rightarrow _{Z-2}^{A-4}\textrm{Y}+_2^4\alpha](https://tex.z-dn.net/?f=_Z%5EA%5Ctextrm%7BX%7D%5Crightarrow%20_%7BZ-2%7D%5E%7BA-4%7D%5Ctextrm%7BY%7D%2B_2%5E4%5Calpha)
For the given alpha decay process of an isotope:
![^{Z}_{A}\textrm{X}\rightarrow ^{208}_{82}\textrm{Pb}+_2^4\alpha](https://tex.z-dn.net/?f=%5E%7BZ%7D_%7BA%7D%5Ctextrm%7BX%7D%5Crightarrow%20%5E%7B208%7D_%7B82%7D%5Ctextrm%7BPb%7D%2B_2%5E4%5Calpha)
<u>To calculate A:</u>
Total mass on reactant side = total mass on product side
A = 208 + 4
A = 212
<u>To calculate Z:</u>
Total atomic number on reactant side = total atomic number on product side
Z = 82 + 2
Z = 84
The isotopic symbol of unknown element is ![_{84}^{212}\textrm{Po}](https://tex.z-dn.net/?f=_%7B84%7D%5E%7B212%7D%5Ctextrm%7BPo%7D)
Hence, the original element is ![_{84}^{212}\textrm{Po}](https://tex.z-dn.net/?f=_%7B84%7D%5E%7B212%7D%5Ctextrm%7BPo%7D)
<span>Cu + 2 AgNO</span>₃<span> = 2 Ag + Cu(NO</span>₃<span>)</span>₂
mole ratio:
1 mole Cu --------------> 2 moles Ag
? mole Cu --------------> 3.50 moles Ag
moles Cu = 3.50 x 1 / 2
moles Cu = 3.50 / 2
= 1.75 moles
Answer B
hope this helps!