Which reaction below is a physical change? a. CH4​(g) + 2O2​(g) → CO2​(g) + 2Hs​O(l)
b. CaO(s) + H2​O(l)→ Ca(OH)2​(s)
c. H2​O (l) → H2​O(s)
D. 2Hs​O (l) → 2H2​(g) + O2​(l)

c. H₂​O (l) → H₂​O(s)

Explanation:

The correct answer is option C: The molecular formulas for the substance(s) on the left side of the equation and on the right side of the equation are identical. This means that there was not a chemical change, but a physical one.

In this concrete example, what happened was a change of states of matter: from liquid (l) to solid (s).

Other reactions have different molecular formulas on both sides of the equation, thus they represent chemical changes.

if two electrons have the same n, the same ℓ, and the same ml, then they are in the same orbital. the pauli exclusion principle states that no two identical fermions (a fancy word for electrons and other subatomic particles like electrons) may occupy the same quantum state in an atom simultaneously.

indicate valleys, hills, steepness and gentleness of slopes.

explanation:

contour lines on a map indicate elevation, or depth. numeric notations on contour lines refer to the level of elevation, or height about sea level.