Answer:
The energy required is 3225 Joules.
Explanation:
Given,
mass of lead cube = 500 grams
T₁ = 25°C
T₂ = 75°C
specific heat of lead = 0.129 J/g°C
Energy required to heat the lead can be found by using the formula,
Q = (mass) (ΔT) (Cp)
Here, ΔT = T₂ - T₁ = 75 - 25 = 50
Substituting the values,
Q = (500)(50)(0.129)
Q = 3225 Joules.
Therefore, energy required is 3225 J.
Answer:

For temperatures higher than 533.49 K we will see a spontaneous reaction, and for temperatures lower than that the reaction will not be spontaneous.
Explanation:
When are chemical reactions spontaneous? To find out we need to look at the reaction's change in Gibbs Free energy:

When this is greater than zero, the reaction isn't spontaneous, when it is less than zero, we have a spontaneous reaction. The reaction must then change from spontaneous to non spontaneous when
. If we insert that into our equation we get:

That is the temperature at which the reaction's spontaneity will change, plugging in our values we find:

At that temperature we have
.
Now, at a temperature greater than this one, the entropy term in our equation for the Gibbs' free energy of reaction will take over, and make
, thus the reaction will be spontaneous.
On the other hand, if we lower the temperature, we will have a smaller entropy term, and we will have:
. That is, the reaction will not be spontaneous. Therefore for temperatures higher than 533.49 K we will see a spontaneous reaction, and for temperatures lower than that the reaction will not be spontaneous.
percent by mass=(mass of solute/ mass of solution)*100 %
mass of solute=58.5 g
density (H₂O)=1 g/cm³*(1000 cm³/1dm³)=1000 g/dm³
mass of solvent (H₂O)=0.5 dm³ * (1000 g/dm³)=500 g
mass of solution=mass of solvent + mass of solut
mass of solution=58.5 g+500 g=558.5 g
% mass=(58.5 g/558.5 g) * 100%=10.47% of Na.
solution: 10.47% of Na.
In given data:
maximum absorption wavelength λ = 580 nm = 580 x 10⁻⁹ m
write the equation to find the crystal field splitting energy:
E = hC / λ
Here, E is the crystal field splitting energy, h = 6.63 x 10⁻³⁴ J.sec is Planck's constant and C = 3 x 10⁸ m/sec is speed of light.
substitute in the equation above:
E = (6.64 x 10⁻³⁴ x 3 x 10⁸) / (580 x 10⁻⁹) = 3.43 x 10⁻¹⁹J
This crystal field splitting energy is for 1 ion.
Number of atoms in one mole, NA = 6.023 x 10²³
to calculate the crystal field splitting energy for one mole:
E(total) = E x NA
= (3.43 x 10⁻¹⁹) x (6.023 x 10²³) = 206 kJ/ mole