Answer:
a. C: +3 ; b. N: +5 ; c. S:+6 ; d. C: +4; e. Mn: +7 ; f. Cr: +6.
Explanation:
Global charges in molecules is 0
You sum all the oxidation states to determine the oxidation state for the compound.
Na₂C₂O₄ → Sodium oxalate → Global charge: 0
Oxidation state for C: +3
HNO₃ → Nitric acid → Global charge: 0
Oxidation state for N: +5
H₂SO₄ → Sulfuric acid → Global charge: 0
Oxidation state for S: +6
HCO₃⁻ → Bicarbonate → Global charge: -1, this is an anion
Oxidation state for C: +4
KMnO₄ → Potassium permanganate → Global charge: 0
Oxidation state for Mn: +7
Cr₂O₇⁻ → Anion dichromate → Global charge: -2
Oxidation state for Cr: +6
Answer:
15.4 g of sucrose
Explanation:
Formula to be applied for solving these question: colligative property of freezing point depression. → ΔT = Kf . m
ΔT = Freezing T° of pure solvent - Freezing T° of solution
Let's replace data given: 0°C - (-0.56°C) = 1.86 C/m . m
0.56°C / 1.86 m/°C = m → 0.301 mol/kg
m → molality (moles of solute in 1kg of solvent)
Our mass of solvent is not 1kg, it is 150 g. Let's convert it from g to kg, to determine the moles of solute: 150 g. 1kg/1000g = 0.150 kg
0.301 mol/kg . 0.150kg = 0.045 moles.
We determine the mass of sucrose, by the molar mass:
0.045 mol . 342 g/1mol = 15.4 g