The Kj of heat that are needed to completely vaporize 1.30 moles of H2O if the heat of vaporization for water is 40.6 Kj/mole is calculated as below
Q(heat) = moles x heat of vaporization)
=1.30 mol x40.6 kj/mol= 52.78 Kj is needed
<span>Which of the following is an electronic device that measures pH?
</span><span>a. a pH meter</span>
Answer:
-219
Explanation:
1.5(339) - 1.5(485) = -219
mass defect = mass of constituents - mass of atom
N has 7p and 9n
proton mass ~ 1.00728 amu
neutron mass ~ 1.00866 amu
electron mass ~ 0.000549 amu
Nitrogen mass ~ 14.003074 amu
mass defect = (7*1.00728)-(7*1.00866)-(7*0.000549)
- 14.003074
= 0.11235amu
convert to energy, the binding energy = 1.68x10^-11 J
Answer:Cell reaction is going forward.
Explanation:
For any chemical reaction to be spontaneous or to move in forward direction the ΔG ,the Gibbs free energy must be negative.
The cell potential of a battery is positive for a spontaneous reaction, so for a battery to give output its cell potential must be positive.
Thermodynamics and electro-chemistry are related in the following manner:
ΔG=-nFE
n=number of electrons involved
F=Faradays constant
E=cell pottential of battery
so from the above equation ΔG would only be negative when E cell that is the cell potential is positive.
For a battery which is being used its cell potential is positive and hence the ΔG would be negative. So the cell reaction occurring would be in forward direction as ΔG is negative.
when the cell potential Ecell is 0 then ΔG is also zero then the reaction occurring in battery would be at equilibrium.
When the cell potential Ecell is - then ΔG is positive and the reaction would be occurring backwards.
