Answer:
A
Explanation:
In this question, we are to calculate the enthalpy of change of the reaction. ΔH
To be able to do that, we use the Hess’ law and it involves the subtraction of the summed heat reaction of the reactants from that of the product.
Thus, mathematically, the enthalpy of change of the reaction would be;
[ΔH(CCl4) + 4 ΔH(HCl)] - [ΔH(CH4) + 4 ΔH(Cl2)]
We can see that we multiplied some heat change by some numbers. This is corresponding to the number of moles of that compound in question in the reaction.
Also, for diatomic gases such as chlorine in the reaction above, the heat of reaction is zero.
Thus, we can have the modified equation as follows;
[ΔH(CCl4) + 4 ΔH(HCl)] - [ΔH(CH4)]
Substituting the values we have according to the question, we have;
-95.98 + 4(-92.3) -(-17.9)
= -95.98 - 369.2 + 17.9
= -447.28 KJ/mol
Answer : The concentration of 
needed is, 
Explanation :
First we have to calculate the mole of phosphate.
As we are given that, 1 mg P/L that means, 1 mg of phosphate present in 1 L of solution.
Molar mass of phosphate = 94.97 g/mole
Now we have to calculate the concentration of phosphate.
Now we have to calculate the concentration of .
The second equilibrium reaction is,
The solubility constant expression for this reaction is:
![K_{sp}=[Fe^{3+}][PO_4^{3-}]](https://tex.z-dn.net/?f=K_%7Bsp%7D%3D%5BFe%5E%7B3%2B%7D%5D%5BPO_4%5E%7B3-%7D%5D)
Given: 
![\frac{1}{4}=[Fe^{3+}]\times 1.053\times 10^{-5}mol/L](https://tex.z-dn.net/?f=%5Cfrac%7B1%7D%7B4%7D%3D%5BFe%5E%7B3%2B%7D%5D%5Ctimes%201.053%5Ctimes%2010%5E%7B-5%7Dmol%2FL)
![[Fe^{3+}]=2.37\times 10^4M](https://tex.z-dn.net/?f=%5BFe%5E%7B3%2B%7D%5D%3D2.37%5Ctimes%2010%5E4M)
Thus, the concentration of needed is,
Answer:
NaS2 has two elements within: Sodium & Sulfur.
Basically, the mass percentage of Na2S is:
Sodium = 58.914%
Sulfur = 41.086%
In total, that would equal: 100%.
Explanation:
Well, we know this because Na (Sodium) has 2 atoms & Sodium has no number after it so, that would be an ordinary one atom.
So, knowing that there are more Sodium's than Sulfur, the mass percentage would be higher, than the percentage of Sulfur.
Answer:
Molecules are made of atoms.
