The density would be the same for the whole bar as well as one half of the bar. Density is a identity I believe, by this I mean that it stays the same no matter how little or how much of the same substance you have. Since density = mass / volume, half the bar has half of the weight as well as half of the volume of the whole bar, making the density the same.
For example, a block weighs 10 grams and has a volume of 5 ml. the density would be d = 10/5 or, d = 2g/ml
Half of the block weighs 5 grams and has a volume of 2.5 ml. The density is d = 5/2.5, or, d = 2 g/ml.
See, although there are different amounts of the same substance, their density is the same.
Answer : The correct option is, +91 kJ/mole
Solution :
The balanced cell reaction will be,
![Cu(s)+Pb^{2+}(aq)\rightarrow Cu^{2+}(aq)+Pb(s)](https://tex.z-dn.net/?f=Cu%28s%29%2BPb%5E%7B2%2B%7D%28aq%29%5Crightarrow%20Cu%5E%7B2%2B%7D%28aq%29%2BPb%28s%29)
Here copper (Cu) undergoes oxidation by loss of electrons, thus act as anode. Lead (Pb) undergoes reduction by gain of electrons and thus act as cathode.
First we have to calculate the standard electrode potential of the cell.
![E^0_{[Pb^{2+}/Pb]}=-0.13V](https://tex.z-dn.net/?f=E%5E0_%7B%5BPb%5E%7B2%2B%7D%2FPb%5D%7D%3D-0.13V)
![E^0_{[Cu^{2+}/Cu]}=+0.34V](https://tex.z-dn.net/?f=E%5E0_%7B%5BCu%5E%7B2%2B%7D%2FCu%5D%7D%3D%2B0.34V)
![E^0_{cell}=E^0_{cathode}-E^0_{anode}](https://tex.z-dn.net/?f=E%5E0_%7Bcell%7D%3DE%5E0_%7Bcathode%7D-E%5E0_%7Banode%7D)
![E^0_{cell}=E^0_{[Pb^{2+}/Pb]}-E^0_{[Cu^{2+}/Cu]}](https://tex.z-dn.net/?f=E%5E0_%7Bcell%7D%3DE%5E0_%7B%5BPb%5E%7B2%2B%7D%2FPb%5D%7D-E%5E0_%7B%5BCu%5E%7B2%2B%7D%2FCu%5D%7D)
![E^0_{cell}=-0.13V-(0.34V)=-0.47V](https://tex.z-dn.net/?f=E%5E0_%7Bcell%7D%3D-0.13V-%280.34V%29%3D-0.47V)
Now we have to calculate the standard Gibbs free energy.
Formula used :
![\Delta G^o=-nFE^o_{cell}](https://tex.z-dn.net/?f=%5CDelta%20G%5Eo%3D-nFE%5Eo_%7Bcell%7D)
where,
= standard Gibbs free energy = ?
n = number of electrons = 2
F = Faraday constant = 96500 C/mole
= standard e.m.f of cell = -0.47 V
Now put all the given values in this formula, we get the Gibbs free energy.
![\Delta G^o=-(2\times 96500\times (-0.47))=+90710J/mole=+90.71kJ/mole\approx +91kJ/mole](https://tex.z-dn.net/?f=%5CDelta%20G%5Eo%3D-%282%5Ctimes%2096500%5Ctimes%20%28-0.47%29%29%3D%2B90710J%2Fmole%3D%2B90.71kJ%2Fmole%5Capprox%20%2B91kJ%2Fmole)
Therefore, the standard Gibbs free energy is +91 kJ/mole
Answer:
n = 0.324 mol
Explanation:
PV = nRT
STP:
273.15K and 101.325kPa
n = PV/RT
n = (101.325kPa)(7.27L)/(8.314 L kPa/mol K)(273.15K)
n = 0.3243693408 mol
n = 0.324 mol
Hope that helps
Answer: A suspension is a heterogenous mixture containing large particles that will settle on standing. Sand in water is an example of a suspension. A solution is a homogenous mixture of two or more substances where one substance has dissolved the other.
Answer:
answer is in exaplation
Explanation:
Answer. Chemical reaction had occurred and both the powders are different substances.
Explanation:
As density is an intensive property of the substance.Which means that different substance have different densities.
Density = \frac{mass}{volume}
volume
mass
Density of powder 1, d_1=\frac{0.5g}{45cm^3}=0.11g/cm^3d
1
=
45cm
3
0.5g
=0.11g/cm
3
Density of powder 2, d_2=\frac{1.3g}{65cm^3}=0.02g/cm^3d
2
=
65cm
3
1.3g
=0.02g/cm
3
On comparing both the densities of the powders we can say that both the substances are different. So we can conclude that the chemical reaction had occurred.