The correct answer is B. 
Explanation
The question provides us with information about the concentration of ![[OH^{-} ]](https://tex.z-dn.net/?f=%5BOH%5E%7B-%7D%20%5D)
and we are supposed to use this information to find the ![[H^{+} ]](https://tex.z-dn.net/?f=%5BH%5E%7B%2B%7D%20%5D)
concentration. The pH of a solution gives us information about
If we the reaction is in equilibrium and with standard conditions of 25°C, then pH is given by the formula
.
Once we find the pH we use the relationship ![pH= -log[H^{+} ]](https://tex.z-dn.net/?f=pH%3D%20-log%5BH%5E%7B%2B%7D%20%5D)
, then the ,is given by
![pH = -log[H^{+} ]\\\implies [H^{+} ]= 10^{-pH} = 10^{-5.8}= 1.58 \times 10^{-6}](https://tex.z-dn.net/?f=pH%20%3D%20-log%5BH%5E%7B%2B%7D%20%5D%5C%5C%5Cimplies%20%5BH%5E%7B%2B%7D%20%5D%3D%2010%5E%7B-pH%7D%20%3D%2010%5E%7B-5.8%7D%3D%201.58%20%5Ctimes%2010%5E%7B-6%7D)
Answer:
ionic bond
Explanation:
Covalent bonds are formed when two or more atoms share electrons between them. So two chlorine anions form an ionic bond with one magnesium cation for form MgCl2, a neutral chemical compound.
Here's my best guess
the volume of the unit cell is (385*10^-12)^3=5.7066*10^-29 m^3
multiply by density to get mass
mass = (7 g/cm^3)*(100^3 cm^3 / 1^3 m^3) * 5.7066*10^-29 m^3= 3.99466*10^-22 g
covert to moles
3.99466*10^-22 g * 1 mol / 239.82 g = 1.6657 *10^-24 mol
convert to number of units
1.6657 *10^-24 mol * 6.23*10^23 units/mol = 1.04
385 pm = 3.85*10^(-8) cm
The volume of the unit cell is the cube of that, which is 5.71*10^(-23) cm^3. Since the ratio of mass to volume (i.e. the density) must be the same no matter what amount of TlCl you have, you can say:
7 = x/(5.71*10^(-23)), where x is the mass of the unit cell. Solving for x, you get 4*10^(-22) g.
The mass of a molecule of TlCl is 240 amu, which in grams is 4*10^(-22) g. The mass of the unit cell and the mass of a molecule of TlCl is the same. Therefore there is one formula unit of TlCl per unit cell.
Answer:
43.0 kJ
Explanation:
The free energy (ΔG) measures the total energy that is presented in a thermodynamic system that is available to produce useful work, especially at thermal machines. In a reaction, the value of the variation of it indicates if the process is spontaneous or nonspontaneous because the free energy intends to decrease, so, if ΔG < 0, the reaction is spontaneous.
The standard value is measured at 25°C, 298 K, and the value of free energy varies with the temperature. It can be calculated by the standard-free energy of formation (G°f), and will be:
ΔG = ∑n*G°f products - ∑n*G°f reactants, where n is the coefficient of the substance in the balanced reaction.
By the balanced reaction given:
2NOCl(g) --> 2NO(g) + Cl2(g)
At ALEKS Data tab:
G°f, NOCl(g) = 66.1 kJ/mol
G°f, NO(g) = 87.6 kJ/mol
G°f, Cl2(g) = 0 kJ/mol
ΔG = 2*87.6 - 2*66.1
ΔG = 43.0 kJ
