1.1 Moles / 0.5 Liters = 0.22 Molarity
Answer:
<em> 14, 508J/K</em>
ΔHrxn =q/n
where q = heat absorbed and n = moles
Explanation:
<em>m = mass of substance (g) = 0.1184g</em>
1 mole of Mg - 24g
<em>n</em> moles - 0.1184g
<em>n = 0.0049 moles.</em>
Also, q = m × c × ΔT
<em> Heat Capacity, C of MgCl2 = 71.09 J/(mol K)</em>
<em>∴ specific heat c of MgCL2 = 71.09/0.0049 (from the formula c = C/n)</em>
<em>= 14, 508 J/K/kg</em>
ΔT= (final - initial) temp = 38.3 - 27.2
= 11.1 °C.
mass of MgCl2 = 95.211 × 0.1184 = 11.27
⇒ q = 11.27g × 11.1 °C × <em>14, 508 j/K/kg </em>
<em>= 1,7117.7472 J °C-1 g-1</em>
<em />
<em>∴ ΔHrxn = q/n</em>
<em>=1,7117.7472 ÷ 0.1184 </em>
<em>= 14, 508J/K</em>
Answer: The mass of ice you would need to add to bring the equilibrium temperature of the system to 300 K is
kg.
Explanation:
We know that relation between heat energy and specific heat is as follows.
q = 
As density of water is 1 kg/L and volume is given as 400,000 L. Therefore, mass of water is as follows.
Mass of water = Volume × Density
= 
= 400,000 kg
or, =
g (as 1 kg = 1000 g)
Specific heat of water is 4.2 J/gm K. Therefore, change in temperature is as follows.
= 305 K - 273 K
= 32 K
Now, putting the given values into the above formula and calculate the heat energy as follows.
q =
= 
=
J
or, =
kJ
According to the enthalpy of melting of ice 333 kJ/Kg of energy absorbed by by 1 kg of ice. Hence, mass required to absorb energy of
kJ is calculated as follows.
Mass = 
=
kg
Thus, we can conclude that the mass of ice you would need to add to bring the equilibrium temperature of the system to 300 K is
kg.