Q: What is the change of entropy for 3.0 kg of water when the 3.0 kg of water is changed to ice at 0 °C? (Lf = 3.34 x 105 J/kg)
Answer:
-3670.33 J/K
Explanation:
Entropy: This can be defined as the degree of randomness or disorderliness of a substance. The S.I unit of Entropy is J/K.
Mathematically, change of Entropy can be expressed as,
ΔS = ΔH/T ....................................... Equation 1
Where ΔS = Change of entropy, ΔH = heat change, T = temperature.
ΔH = -(Lf×m).................................... Equation 2
Note: ΔH is negative because heat is lost.
Where Lf = latent heat of ice = 3.34×10⁵ J/kg, m = 3.0 kg, m = mass of water = 3.0 kg
Substitute into equation
ΔH = -(3.34×10⁵×3.0)
ΔH = - 1002000 J.
But T = 0 °C = (0+273) K = 273 K.
Substitute into equation 1
ΔS = -1002000/273
ΔS = -3670.33 J/K
Note: The negative value of ΔS shows that the entropy of water decreases when it is changed to ice at 0 °C
Answer:
35Cl ⇒ 34.968853 amu has an abundance of 30.05%
Explanation:
The molar mass of chlorine, (which is the average of all its naturally stable isotope masses), is 36.36575 amu.
There are 2 naturally stable isotopes, this means together they have an abundance of 100%
The isotopes are:
35Cl ⇒ 34.968853 amu has an abundance of X %
37Cl ⇒ 36.965903 amu has an abundance of Y %
X + Y = 100% OR X = 100% - Y
36.36575 = 34.968853X + 36.965903Y
36.36575 = 34.968853(1-Y) + 36.936.96590365903Y
36.36575 = 34.968853 -34.968853Y + 36.965903Y
1.396897 = 1.99705Y
Y = 0.699 = 69.95%
X = 100-69.9 = 30.05%
To control, we can plug in the following equation:
34.968853 * 0.3005 + 36.965903 * 0.6995 = 36.3658
This means
37Cl ⇒ 36.965903 amu has an abundance of 69.95 %
35Cl ⇒ 34.968853 amu has an abundance of 30.05%
The equilibrium expression shows the ratio between
products and reactants. This expression is equal to the concentration of the
products raised to its coefficient divided by the concentration of the
reactants raised to its coefficient. The correct equilibrium expression for the
given reaction is:<span>
<span>H2CO3(aq) + H2O(l) = H3O+(aq) + HCO3-1(aq)
Kc = [HCO3-1] [H3O+] / [H2O] [H2CO3]</span></span>
Answer:
Accuracy is the closeness to the specific target and precision is the closeness of the measurements to each other.
