The location of the valence electron or the outermost electron is expressed in quantum numbers. There are five quantum numbers: prinicipal (n), angular momentum (l), magnetic (ms) and magnetic spin (ms) quantum numbers. This is based on Bohr's atomic model where electrons orbit around the nucleus. These electrons are in the orbitals with specific energy levels. Starting from energy level 1 that is closest to the nucleus, the energy level decreases to 2, 3, 4, 5, 6, and 7. These energy level numbers represent the principal quantum number. Within each orbital also contains subshell. From increasing to decreasing order, these subshells are the s, p, d and f subshells. These subshells represent the angular momentum quantum numer. Specifically, s=0, p=1, d=2 and f=3. Therefore, if the electron is in the orbital 5p, the quantum number would be: 5, 1. Applying these to the choices, the correct pairing would be:
2p: n=2. l=1
3d: n=3, l=2
2s: n=2. l=0
4f: n=4. l=3
1s: n=1, l=0
Considering the definition of molar mass, the number of moles of Zn reactant used is 2 moles.
<h3>Definition of molar mass</h3>
The molar mass of substance is a property defined as its mass per unit quantity of substance, in other words, molar mass is the amount of mass that a substance contains in one mole.
<h3>Number of moles of Zn used</h3>
The balanced reaction is:
Zn(s) + 2 HCl(aq) → ZnCl₂ + H₂(g)
Assume that 130.8 grams of Zn was used in this reaction.
To determine the number of moles of hydrogen gas formed, you need to know the number of moles of Zn reactant was used.
So to determine the number of moles used you know that the molar mass of Zn is 65.37
. Then:
Solving:
number of moles× 65.37= 130.8 g
<u><em>number of moles≅ 2 moles</em></u>
Finally, the number of moles of Zn reactant used is 2 moles.
Learn more about molar mass:
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Answer: is A
Explanation:
how becuase i just take the test
Answer:
When the water is mixed with water at lower temperature the effective temperature of the system (i.e the water at lower temperature) will increase, thereby increasing it's entropy
Explanation:
The answer that "the entropy will is increases" is correct as:
The water at 90° C i.e at higher temperature is mixed with the water at 10° C i.e the water at the lower temperature.
The water at lower temperature will have molecules with lower energy while the water with higher temperature will have molecules undergoing high thermal collisions. Thereby, when the water is mixed with water at lower temperature the effective temperature of the system (i.e the water at lower temperature) will increase, thereby increasing it's entropy.
Therefore, the answer is correct with respect to the water at lower temperature.
Meanwhile, for the water at higher temperature , the temperature of the system will decrease. Thus, the entropy of the water at higher level will decrease.
