Answer:
2,3–dimethylpentane
Explanation:
To know which option is correct, we shall determine the name of the compound.
To obtain the name of the compound, do the following:
1. Determine the longest continuous carbon chain. This gives the parent name of the compound.
2. Identify the substituent group attached to the compound.
3. Locate the position of the substituent group by giving it the lowest possible count.
4. Combine the above to obtain the name of the compound.
Now, we shall determine the name of the compound as follow:
1. The longest continuous carbon chain is 5. Thus, the parent name of the compound is pentane.
2. The substituent group attached is methyl (–CH₃)
3. There are two methyl group attached to the compound. One is located at carbon 2 and the other at carbon 3.
4. Therefore, the name of the compound is:
2,3–dimethylpentane
None of the options are correct.
Answer:
Molar mass→ 0.930 g / 6.45×10⁻³ mol = 144.15 g/mol
Explanation:
Let's apply the formula for freezing point depression:
ΔT = Kf . m
ΔT = 74.2°C - 73.4°C → 0.8°C
Difference between the freezing T° of pure solvent and freezing T° of solution
Kf = Cryoscopic constant → 5.5°C/m
So, if we replace in the formula
ΔT = Kf . m → ΔT / Kf = m
0.8°C / 5.5 m/°C = m → 0.0516 mol/kg
These are the moles in 1 kg of solvent so let's find out the moles in our mass of solvent which is 0.125 kg
0.0516 mol/kg . 0.125 kg = 6.45×10⁻³ moles. Now we can determine the molar mass:
Molar mass (mol/kg) → 0.930 g / 6.45×10⁻³ mol = 144.15 g/mol
A;4, b;6, c;7, d;5, e;8, f;3