A student listed the characteristics of chemical and nuclear reactions. Chemical and Nuclear Reactions

C:
A change in atomic number of elements takes place
D:
The atomic number of elements remains the same

Which of these statements best explains the identity of Reaction D?
Olt is a nuciear reaction because the atomic number remains the same when the number of valence electrons changes.
Oit is a nuclear reaction because the atomic number remains the same when the particles are emitted from the nucleus.
Oit is a chamical reaction because the atomic number remains the same when the number of neutrons and protons changes.
Oit is a chemical reaction because the atomic number remains the same for all elernents while a rearrangement of atoms through bonding occurs.

odds are decent that your handwriting right now looks a little bit different than it did five years ago, and will look different again in five more. when i look back through my notebooks from middle school to now, i see a long, slow progression from meticulous and teeny letters to bigger, sloppier ones, plus a few side detours: sometime in high school, for example, i decided those loopy cursive lowercase f’s were just the coolest, adopting them as the lone rep for cursive in my otherwise all-print handwriting.

explanation:

1. for the first question, we must find the mass of the anhydrous salt, mgso₄. the molar mass for mgso₄·7h₂o is 246.47 g/mol, while that of mgso₄ is 120.37 g/mol.7.834 g mgso₄·7h₂o * 1 mol mgso₄·7h₂o/246.47 g * 1 mol mgso₄/1 mol mgso₄·7h₂o * 20.37 g mgso₄/mol = 0.647 g mgso₄

2. mass of water = mass of sample - mass of anhydrous salemass of water = 7.834 - 0.647 = 7.19 gpercent water in hydrate = 7.19/7.834 * 100 = 91.74%