Answer:
The SI base unit for amount of substance is the mole. 1 mole is equal to 1 moles C3H8, or 44.09562 grams
Hydrocarbons. They usually burn. In fact, I can't think of one that does not.
<u>Answer:</u> The original element is 
<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.

For the given alpha decay process of an isotope:

<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 
Hence, the original element is 
The scientific study of the origin, history, structure, and composition of the earth.