Answer:
a. electrophilic aromatic substitution
b. nucleophilic aromatic substitution
c. nucleophilic aromatic substitution
d. electrophilic aromatic substitution
e. nucleophilic aromatic substitution
f. electrophilic aromatic substitution
Explanation:
Electrophilic aromatic substitution is a type of chemical reaction where a hydrogen atom or a functional group that is attached to the aromatic ring is replaced by an electrophile. Electrophilic aromatic substitutions can be classified into five classes: 1-Halogenation: is the replacement of one or more hydrogen (H) atoms in an organic compound by a halogen such as, for example, bromine (bromination), chlorine (chlorination), etc; 2- Nitration: the replacement of H with a nitrate group (NO2); 3-Sulfonation: the replacement of H with a bisulfite (SO3H); 4-Friedel-CraftsAlkylation: the replacement of H with an alkyl group (R), and 5-Friedel-Crafts Acylation: the replacement of H with an acyl group (RCO). For example, the Benzene undergoes electrophilic substitution to produce a wide range of chemical compounds (chlorobenzene, nitrobenzene, benzene sulfonic acid, etc).
A nucleophilic aromatic substitution is a type of chemical reaction where an electron-rich nucleophile displaces a leaving group (for example, a halide on the aromatic ring). There are six types of nucleophilic substitution mechanisms: 1-the SNAr (addition-elimination) mechanism, whose name is due to the Hughes-Ingold symbol ''SN' and a unimolecular mechanism; 2-the SN1 reaction that produces diazonium salts 3-the benzyne mechanism that produce highly reactive species (including benzyne) derived from the aromatic ring by the replacement of two substituents; 4-the free radical SRN1 mechanism where a substituent on the aromatic ring is displaced by a nucleophile with the formation of intermediary free radical species; 5-the ANRORC (Addition of the Nucleophile, Ring Opening, and Ring Closure) mechanism, involved in reactions of metal amide nucleophiles and substituted pyrimidines; and 6-the Vicarious nucleophilic substitution, where a nucleophile displaces an H atom on the aromatic ring but without leaving groups (such as, for example, halogen substituents).
Answer:
An alloy is the combination of metals homogeneously.
Explanation:
Alloys can also include other elements in combination with metals e.g carbon and Iron forms steel.
Alloys find a host of application in various industries and domestic use.
Alloying of metals helps to improve the physical and chemical properties of such materials better.
Some materials are alloyed to improve their strength.
Alloying can help heat and electrical conduction of a substance.
Alloys can greatly prevent rusting and produce corrosion resistant metals.
Alloys can provide a better means for a material to be worked.
Alloys can be more durable than original materials.
Explanation:
(a). The given data is as follows.
Volume of one glass of water = 
ml = 220 ml
Volume of 4 glass of water = 
= 880 ml
We known that density of water is 1 g/ml. Therefore, calculate the mass of water as follows.
Mass of water = 
= 880 gm
= 0.88 Kg (as 1 kg = 1000 g)
The relation between heat energy, mass and temperature change is as follows.
Q = 
Putting the given values into the above formula as follows.
Q =
= 
= 124.5 kJ
Hence, the body have to supply 124.5 kJ to raise the temperature of the water to 37 degree C.
(b). As we know that the heat of fusion of ice is 333 J/g.
So, energy required for 
g or 840 g is as follows.
= 279.72 kJ
Heat capacity of water= 4.184 
Now, heat energy will be as follows.
Q = 
= 130.03 kJ
Therefore, total heat required = (279.72 + 130.03) kJ
= 409.75 kJ
Hence, for the given situation your body should lose 409.75 kJ of heat.
It will always produce a near-exact measurement
I understand here "bias" to be the uncertainty of measurements. So the order will be the following:
6.4 ± 0.5 s
<span>6.6 ± 0.1 s,
</span><span>6.63 ± 0.01 s,
</span><span>6.52 ± 0.05 s,
</span>
(notice how the second number, the one behind the symbol ± gets smaller, as the bias gets smaller).
