Answer:
B
Explanation:
Isotopy is a phenomenon in which there exists two or more kind of atoms of the same element. These atoms have the same number of protons but different mass numbers. That is, they have the same atomic number but differ only by the number of neutrons in the nucleus of the atom. Now, let us apply this information to the options individually:
A. Is wrong, they are not the same element
B. Is correct. they both belong to the same element hydrogen. Infact, they are named protium and deuterium respectively
C is wrong they are not same element
D is wrong They are not elements at all
E. Is wrong, one is an element, the other is a molecule
Answer:
Equation correctly showing the heat of solution
Explanation:
Mass of aqueous solution = m = 100 g
Specific heat of solution = c = 4.18 J/gºC
Change in temperature = 
ΔT = 21.6ºC - 30.0ºC = -8.4ºC
Heat lost by the solution = Q
Q = -3,511.2 J ≈ -3.51 kJ
Heat absorbed by potassium nitrate when solution in formed; Q'
Q' = -Q = 3.51 kJ
Moles of potassium nitrate , n= 
The heat of solution =
So, the equation correctly showing the heat of solution
Magnesium plus chlorine equals to magnesium chloride
Mg(c) + 237shi (4z) ¥at h2)
Corroding iron. The reason why iron corrodes is that it reacts with the oxygen in the air to create iron oxide which is what we call rust. when iron turns to rust, the chemical identity of the iron changes.
when you break ice, the ice is still ice. that water did not change into something else. when you run a current through copper, the electrons in the copper move due to the voltage but the copper is not changing. After the circuit stops, the copper wires are still made out of copper (the copper did not undergo a chemical change). When you melt gold, the gold is only going from solid form to liquid form. The gold has not changed chemically, it just underwent a phase change.
I hope this helps. Let me know if anything is unclear.
