Answer:
THE FREEZING POINT OF A WATER SOLUTION OF FRUCTOSE MADE BY DISSOLVING 92 g OF FRUCTOSE IN 202g OF WATER IS -4.70 ◦C
Explanation:
To calculate the freezing point of a water solution of fructose,
1. calculate the molar mass of Fructose
( 12 * 6 + 1*12 + 16*6) =72 + 12 +96 = 180 g/mol
2. calculate the number of moles of fructose in the solution
number of moles = mass / molar mass
n = 92 g / 180 g/mol
n = 0.511 moles.
3. calculate the molarity of the solution
molarity = moles / mass of water in kg
molarity = 0.5111 / 202 g /1000 g
molarity = 0.5111 / 0.202
molarity = 2.529 M
4. calculate the change in the freezing point of pure solvent and solution ΔTf
ΔTf = Kf * molarity of the solute
Kf = 1.86 ◦C/m for water
ΔTf = 1.86 * 2.529
ΔTf = 4.70 C
5. the freezing point is therefore
0.00 ◦C - 4.70 ◦C = -4.70 ◦C
Answer:
Pb(NO₃)₂ (aq) + 2NaCl (aq) → PbCl₂ (s) ↓ + 2NaNO₃ (aq)
Explanation:
The reactants are:
Lead(II) nitrate → Pb(NO₃)₂ (aq)
Sodium chloride → NaCl (aq)
The products are:
Lead(II) chloride → PbCl₂ (s)
Sodium nitrate → NaNO₃ (aq)
Salts form nitrate are soluble. The chloride makes a precipitate with the Pb²⁺. The chemical equation for this reaction is:
Pb(NO₃)₂ (aq) + 2NaCl (aq) → PbCl₂ (s) ↓ + 2NaNO₃ (aq)
Answer:
See figure 1
Explanation:
We have to remember that in the isomer structures we have to <u>change the structure</u> but we have to maintain the <u>same formula</u>, in this case 
.
In the formula, we have 1 nitrogen atom. Therefore we will have as a main functional group the <u>amine group</u>.
In the amines, we have different types of amines. Depending on the number of carbons bonded to the "N" atom. In the <em>primary amines</em>, we have only 1 C-H. In the <em>secondary amines</em>, we have two C-N bonds and in the <em>tertiary amines</em>, we have three C-N bonds.
With this in mind, we can have:
-) <u>Primary amines:</u>
1) n-butyl amine
2) sec-butyl amine including 2 optical isomers
3) isobutyl amine
4) tert-butyl amine
-) <u>Secondary amines:</u>
5) N-methyl n-propyl amine
6) N-methyl isopropyl amine
7) N, N-diethyl amine
-) <u>Tertiary amines:</u>
8) N-ethyl N, N-dimethyl amine
See figure 1
I hope it helps!
