<span>Well... first, let's recognize that the chemical formula for chlorodifluoromethane is CHClF2. Count out how many valence electrons there are. C = 4, H = 1, Cl = 7, F (X2) = 14. Total is 26. Let's put C as the central atom, and put the other elements surrounding it. Draw a pair of electrons beach each element and the central atom. Then fill the halogen elements with 3 pairs of electrons each to fill their octets. Count out how many dots you have. There should be 26, making this the correct lewis structure!
Remember, hydrogen doesn't have a full octet, only a maximum of two electrons.</span>
First convert the amount of grams you have of each substance to moles. Find your limiting reactant by calculating how many grams are needed to complete this reaction. If done correctly, you would see that we need .226 moles of Potassium to complete this reaction. However, we only have .118 moles of Potassium, so K must be our limiting reactant. Then use the moles of K to find out how many moles of K^2S are made. Then convert the amount of moles of K^2S to grams and you should get 10.3 g K^2S
Answer:
Negative sign says that release of heat.
Explanation:
The expression for the calculation of the heat released or absorbed of a process is shown below as:-
Where,
is the heat released or absorbed
m is the mass
C is the specific heat capacity
is the temperature change
Thus, given that:-
Mass = 25.2 g
Specific heat = 0.444 J/g°C
So,
Negative sign says that release of heat.
4. Blue, Red, Green, Purple
(Lowest densities on the top, highest densities on the bottom)
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.
