When ice melts, the physicals state changes from solid to liquid. The energy or the heat required (q) required to change a unit mass (m) of a substance from solid to liquid is known as the enthalpy or heat of fusion (ΔHf). The variables; q, m and ΔHf are related as:
q = m * ΔHf
the mass of ice m = 65 g
the heat of fusion of water at 0C = ΔHf = 334 J/g
Therefore: q = 65 g * 334 J/g = 21710 J
Now:
4.184 J = 1 cal
which implies that: 21710 J = 1 cal * 21710 J/4.184 J = 5188.8 cal
Hence the heat required is 5188.8 cal or 5.2 Kcal (approx)
The first ionization energy of a known element is the energy
it needs to remove its highest energy or outermost electron. It is done to make
a neutral atom be a positively charged ion. The first ionization energy of neon
as a chemical equation is this:
Ne (g) -> Ne+ (g) + e-
Answer:
See explanation
Explanation:
The number of electrons in each principal energy shell increases as the number of shells increases because more electronic orbitals become available to accommodate the electrons.
For instance, the n= 2 level only accommodates eight electrons in the s and p orbitals whereas the n=3 level accommodates 18 electrons in s, p and d orbitals respectively.
Each principal level accommodates 2n^2 electrons where n= the principal energy shell.
The statement which is true is
Fluorine is more reactive than nitrogen because fluorine needs only one electron to fill its outermost shell.
<u><em>Explanation</em></u>
Fluorine has electron configuration of 1S²2S²2P⁵ while nitrogen has 1S²2S²2P³ electron configuration.
The 2P sub shell for nitrogen is half filled therefore it is sable than fluorine.
since p orbital can hold a maximum of 6 electrons ,Fluorine requires 1 electron to completely fill it's 2P sub shell which make it more reactive than nitrogen.
An acid-base reaction or a neutralization reaction is a <u>chemical reaction that occurs between an acid and a base producing a salt and water</u>. The acids and bases can be strong or weak depending on their degree of ionization in water.
Butyric acid is a weak acid and in water it is ionized in the following way, loosing a proton (H+):
HC4H7O2 (aq) ⇆ H+ (aq) + C4H7O2- (aq)
On the other hand, potassium hydroxide is a strong base, so it will be completely ionized in water:
KOH(aq) → K+(aq) + OH-(aq)
Then the <u>net acid-base reaction</u> between butyric acid and KOH is:
HC4H7O2 (aq) + OH- (aq) ⇆ H2O + C4H7O2- (aq)
It is valid to consider only the OH- produced from the ionization of KOH in water since, as mentioned, this molecule is completely ionized. Also, we do not include the K + in the net equation since it is a spectator ion, it does not undergo chemical changes.
