Answer: 27 neutrons
Explanation:
Recall that the number of protons in the nucleus of an atom = Atomic number.
Hence, Calcium with mass number 47 and atomic number 20 will have 20 protons
Therefore, since Mass number = number of protons + neutrons
47 = 20 + neutrons
Neutrons = 47 - 20 = 27
Thus, there are 27 neutrons in radioactive calcium nucleus.
This is because, for the main reason that these elements that are mostly monatomic, are unreactive, they do not react, or in other words, exchange, and or share valence electrons through chemical bonds, as they already posses the maximum number of valence electrons in their valence shell, which is 8.
Answer:
Bonds are broken and new bonds are formed during chemical reactions only.
Explanation:
- A physical change in a substance doesn't change what the substance is.
- In a chemical change where there is a chemical reaction, a new substance is formed and energy is either given off or absorbed.
- Physical changes can be reversed, chemical changes cannot be reversed with the substance changed back without extraordinary means, if at all. For example, a cup of water can be frozen when cooled and then can be returned to a liquid form when heated.
So, the right choice is:
Bonds are broken and new bonds are formed during chemical reactions only.
Answer:
.500
Explanation:
Use the ideal gas law equation: PV = nRT
Plug in the initial values given:
P = 1.2 atm
V = .500 L
n = number of moles
R = Gas Constant 8.314
T = 25.0 C
(1.2)(.5) = n(8.314)(25)
solving for n we get .00289
Now use the same equation with the new values solving for V
(3.6)V = (.00289)(8.314)(75.0)
V = .4999999 ROund to .500
Many electrophilic aromatic halogenations require the presence of an aluminum trihalide as a catalyst. We generally acetylated the amino group as protection. Now, this acetanilide can be brominated at Ortho or para position. An atom that is attached to an aromatic system usually hydrogen is replaced by an electrophile is an organic reaction which is called Electrophilic aromatic substitution. There are what you called important electrophilic aromatic substitutions they are aromatic nitration, aromatic sulfonation, aromatic halogenation and acylation and alkylating Friedel-Crafts reaction. Aromatic bromination is an electrophilic aromatic substitution (EAS) reaction, which will require benzene to act as a nucleophile to acquire an electrophile. Therefore, any directing groups that activate the ring will make it react more quickly with respect to aromatic bromination. Acetanilide is a moderately-activated ring <span>having a decent EWG.</span>
