Answer:
Although PPT was initially prepared from terephthalic acid (TPA) and 1,3-propanediol (PDO) in the 1950s, it has been mainly synthesized by transesterification of PDO with dimethyl terephthalate (DMT) similar to poly(ethylene terephthalate) (PET) and poly(butylene terephthalate) (PBT).
Explanation:
Na₂CO₃(s) → 2Na⁺(aq) + CO₃²⁻(aq)
The sodium carbonate formed from a strong base and a weak acid. Hydrolysis is subjected to the anion of a weak acid.
CO₃²⁻ + H₂O ⇄ HCO₃⁻ + OH⁻
HCO₃⁻ + H₂O ⇄ H₂CO₃ + OH⁻
pH>7 alkaline solution
2Na⁺ + CO₃²⁻ + 2H₂O ⇄ 2Na⁺ + 2OH⁻ + H₂CO₃
Answer:
yeyeye
Explanation:
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Answer:
Na₂CO₃.2H₂O
Explanation:
For the hydrated compound, let us denote is by Na₂CO₃.xH₂O
The unknown is the value of x which is the amount of water of crystallisation.
Given values:
Starting mass of hydrate i.e Na₂CO₃.xH₂O = 4.31g
Mass after heating (Na₂CO₃) = 3.22g
Mass of the water of crystallisation = (4.31-3.22)g = 1.09g
To determine the integer x, we find the number of moles of the anhydrous Na₂CO₃ and that of the water of crystallisation:
Number of moles = 
Molar mass of Na₂CO₃ =[(23x2) + 12 + (16x3)] = 106gmol⁻¹
Molar mass of H₂O = [(1x2) + (16)] = 18gmol⁻¹
Number of moles of Na₂CO₃ = 
= 0.03mole
Number of moles of H₂O = 
= 0.06mole
From the obtained number of moles:
Na₂CO₃ H₂O
0.03 0.06
Simplest
Ratio 0.03/0.03 0.03/0.06
1 2
Therefore, x = 2
Answer:
Option e.
Explanation:
The option 'e' fact about Hydrogen bonds are correct, that is; ''form weak interactions but can provide structural stability when many are found in a single molecule''.
So, what is this Hydrogen bond?
Hydrogen bonds is a kind of strong dipole- dipole attractions. Hydrogen bonding occurs as a result of the bonding between hydrogen and strongly electronegative atoms for example oxygen, Fluorine and so on.
Since we now know what Hydrogen bond is, let us take a look at the options.
(a) for the first option, we can see from above meaning of Hydrogen bonds that Hydrogen bonds occur between Hydrogen and a strong Electronegative atom. So, this option is wrong.
(b). Option 'b' is also wrong Because Hydrogen bonds does not occur between hydrogen and oxygen atoms ONLY but also with other strong Electronegative atoms such as oxygen.
(c). Option 'c' is wrong because between a strong and not only between a weak electronegative atom and hydrogen.
(d). Option 'd' is also not correct.
(e). Option 'e' is correct. Hydrogen bonds contribute to the effect of boiling and melting point of substance, solubilty, dimerization, strength of bonds, shape of molecules and so on
