Answer: m = 0.42; Tb = 79°
Explanation: The relationship between boiling point of the solvent above a solution is directly proportional to the molal concentration of the solute, i.e.:
ΔT = 
where
ΔT is the change in boiling point of the solvent;
is the molal boiling point elevation constant;
m is the molal concentration of the solute in the solution;
For there two solutions:
1) Ethanol:
ΔT =
Tb - 
Tb - 78.4 = 1.22.m (1)
2) Carbon Tetrachloride:
Tb -
Tb - 76.8 = 5.03.m (2)
Solving the system of equations:
Tb - 78.4 = 1.22.m
Tb = 1.22.m + 78.4 (3)
Substituing (3) in (2)
1.22.m + 78.4 - 76.8 = 5.03m
3.81m = 1.6
m = 0.42
With m, find Tb:
T - 76.8 = 5.03.0.42
T = 2.11 + 76.8
T = 79°
<u>Molal</u> concentration is <u>0.42</u> and boiling point is 79°
Answer:
About 2 liters
Explanation:
Since 1 gallon equals 3.785 liters, you figure out how many liters per week she uses by 3.785 x 0.75 which is 2.83875. Then divide that by 7 which is 0.405535 liters per day. Then multiply that by 5 days which is 2.027 liters in 5 days.
Based on Hess's Law:
<span>2 N2(g) + 6 O2(g) + 2 H2(g) −→ 4 HNO3(l) ∆Hf = (−171.9 kJ/mol)(4 mol) </span>
<span>2 H2O(l) −→ 2 H2(g) + O2(g) ∆Hf = (-283.8 kJ/mol)(2 mol)(-1) →times -1, rxn is reversed </span>
<span>4 HNO3(l)−→ 2 N2O5(g) + 2 H2O(l) ∆Hf = (-76.4 kJ/mol)(2 mol)(-1) →times -1, rxn is reversed </span>
<span>2 N2(g) + 5 O2(g) −→ 2 N2O5(g) ∆H0 = 32.8 kJ</span>
Well without natural resources wood have no water, Fruits,Wood,Rocks,Air and Coal or petroleum many things we need to live.
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