Answer:
ΔQ = - 762 J (Negative Sign shows heat transfer from the system)
Explanation:
The heat transferred to or from the system can be given by using First law of Thermodynamics as follows:
where,
ΔQ = Heat Transferred to or from system = ?
ΔU = Change in Internal Energy of System = Change in Thermal Energy
ΔU = - 240 J (negative sign due to decrease in energy)
W = Work done on system = -522 J (negative sign due to work done "on" system)
Therefore,
<u>ΔQ = - 762 J (Negative Sign shows heat transfer from the system)</u>
The last one, the soil will become weak & unable to support plant growth
Answer:a
Explanation:
Given
![[H^+]=5.3\times 10^{-4}\ M](https://tex.z-dn.net/?f=%5BH%5E%2B%5D%3D5.3%5Ctimes%2010%5E%7B-4%7D%5C%20M)
and 
Also ![pH=-\log [H^+]](https://tex.z-dn.net/?f=pH%3D-%5Clog%20%5BH%5E%2B%5D)
therefore 
Thus 
and ![pOH=-\log [OH^{-}]](https://tex.z-dn.net/?f=pOH%3D-%5Clog%20%5BOH%5E%7B-%7D%5D)
![[OH]^{-1}=10^{-10.25}](https://tex.z-dn.net/?f=%5BOH%5D%5E%7B-1%7D%3D10%5E%7B-10.25%7D)
![[OH]^{-1}=1.88\times 10^{-11}\ M](https://tex.z-dn.net/?f=%5BOH%5D%5E%7B-1%7D%3D1.88%5Ctimes%2010%5E%7B-11%7D%5C%20M)
As the pH is less than 7 therefore solution is acidic
I believe that the correct given values are:
density = 755 kg/m^3
volume = 640 cm^3
First let us convert volume to m^3 units.
volume = 640 cm^3 * (1 m / 100 cm)^3 = 6.4 x 10^-4 m^3
so the mass is:
mass = 755 kg/m^3 * (6.4 x 10^-4 m^3)
<span>mass = 0.4832 kg = 483.2 g</span>
Heat released from combustion is calculated by multiplying the amount of substance being burned with its heat of combustion. From this, we can calculate the mass needed from the system above. The calculation is as follows:
-543 kJ = x x -1320 kJ/mol
x = 0.411 mol
Mass of x = 0.411 x 71.83 g/mol
Mass of x = 29.55 g
