How much heat is lost when 575 grams molten iron at 1825 k becomes solid iron at 293 k? The melting point or iron is 1811 k.
1 answer:
Answer:
146 kJ
Explanation:
There are two heat flows in this question.
Heat lost on cooling + heat lost on solidifying = 0
q₁ + q₂ = 0
mCΔT + nΔHsol = 0
Data:
m = 575 g
C = 0.449 J·K⁻¹g⁻¹
T_i = 1825 K
T_f = 1811 K
ΔHsol = -13.8 kJ·mol⁻¹
Calculations:
(a) Heat lost on cooling
ΔT = T_f - T_i = 1811 K - 1825 K = -14 K
q₁ = mCΔT = 575 g × 0.449 J·K⁻¹g⁻¹ × (-14 K) = -361 J = -3.61 kJ
(b) Heat lost on solidifying
(c) Total heat lost
q = q₁ + q₂ = -3.61 kJ - 142.1 kJ = -146 kJ
The heat lost was 146 kJ.
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Answer:
a)
In Boyle's Law, the variable that remains constant is the absolute temperature of the gas.
In Charle's Law, the variable that remains constant is the pressure of the gas.
In Avogadro's Law, the variables that remain constant are pressure and temperature of the gas.
b)
In Boyle's Law, the variables involved are pressure and volume: the law states that for a fixed mass of ideal gas at constant temperature, the pressure of the gas is inversely proportional to the volume:
where p is the pressure of the gas and V the volume.
In Charle's Law, the variables involved are volume and temperature: the law states that for a fixed mass of ideal gas at constant pressure, the volume of the gas is directly proportional to the temperature:
where V is the volume of the gas and T the temperature.
In Avogadro's Law, the variables involved are the volume and the number of moles: the law states that for an ideal gas kept at constant pressure and temperature, the volume of the gas is directly proportional to the number of moles:
Where V is the volume of the gas and n the number of moles.
c)
See the graphs of the three Laws in attachment:
- First graph: Boyle's Law, which shows that the pressure of the gas is inversely proportional to the volume
- Second Graph: Charle's Law, which shows that the volume of the gas is directly proportional to the absolute temperature
- Third graph: Avogadro's Law, which shows that the volume of the gas is directly proportional to the number of moles of the gas
d)
Here we want to re-write the three laws by making V the subject.
For Boyle's law, we get:
For Charle's Law, we get:
For Avogadro's Law, we get:
Therefore, we see that the two laws that show a direct proportionality are Charle's Law and Avogadro's Law, while Boyle's Law shows an inverse proportionality between the two variables.
Answer:
<h2>1.74 g/mL</h2>Explanation:
The density of a substance can be found by using the formula
From the question we have
We have the final answer as
<h3>1.74 g/mL</h3>Hope this helps you