The concentration of A will be <em>0.34 mol·L⁻¹</em> after 60 min.
In a first-order reaction, the formula for the amount remaining after <em>n</em> half-lives is
![\text{[A]} = \frac{\text{[A]}_{0}}{2^{n}}\\](https://tex.z-dn.net/?f=%5Ctext%7B%5BA%5D%7D%20%3D%20%5Cfrac%7B%5Ctext%7B%5BA%5D%7D_%7B0%7D%7D%7B2%5E%7Bn%7D%7D%5C%5C)
If 
∴ ![\text{[A]} = \frac{\text{2.7 mol/L}}{2^{3.0}} = \frac{\text{2.7 mol/L}}{8.0} = \textbf{0.34 mol/L}](https://tex.z-dn.net/?f=%5Ctext%7B%5BA%5D%7D%20%3D%20%5Cfrac%7B%5Ctext%7B2.7%20mol%2FL%7D%7D%7B2%5E%7B3.0%7D%7D%20%3D%20%5Cfrac%7B%5Ctext%7B2.7%20mol%2FL%7D%7D%7B8.0%7D%20%3D%20%5Ctextbf%7B0.34%20mol%2FL%7D)
Answer:
237.8L of water would need to be added.
Explanation:
The first thing to do is to identify that the equation to be used is M1V1=M2V2. (This equation works because it turns everything into moles which can then be compared).
Then figure out what information you have and what is being found. In this case:
M1 = 54.7 M
V1 = 1092 mL = 1.092 L
M2 = 0.25 M
V2 = unknown
Then solve the equation for whatever you are trying to find.
M1V1=M2V2
V2=M1V1/M2
Now you need to plug everything in.
V2=(54.7M*1.091L)/0.25M
V2=238.93L
That means that the solution needs a volume of 238.7L to gain a molarity of 0.25M but the starting solution already had a volume of 1.092 L meaning that to find the amount of solvent that needs to be added you just subtract the starting volume by the volume that the solution needs to be.
238.93L - 1.091L = 237.8L
Therefore the answer is that 237.8L needs to be added to a 1.092L 54.7M NaCl solution to make the concentration 0.25M.
I hope this helps. Let me know if anything is unclear.
Answer:
Cobaltous Nitride,I think so anyway.......
Answer:
Potassium
General Formulas and Concepts:
<u>Chem</u>
- Reading a Periodic Table
- Periodic Trends
- Ionization Energy - energy required to remove an electron from a given element
- Coulomb's Law
- Shielding Effect
- Z-effective and Forces of Attraction
Explanation:
The Periodic Trend for 1st Ionization Energy is increasing up and to the right. That means He would have the highest I.E and therefore take the most amount of energy to remove an electron.
Potassium and Gallium are both in Period 4. Potassium is element 19 and Gallium is element 31.
Potassium's electron configuration is [Ne] 4s¹ and Gallium's electron configurations is [Ne] 4s²3d¹⁰4p¹. Since both are in Period 4, they have the same number of core e⁻. Therefore, the shielding effect is the same.
However, since Gallium is element 31, it has 31 protons compared to Potassium, which is element 19 and has 19 protons. Gallium would have a greater Zeff than Potassium as it has more protons. Therefore, the FOA between the electrons and nucleus of Ga is much stronger than that of K. Thus, Ga requires <em>more</em> energy to overcome those FOA to remove the 4p¹ e⁻. Since K has less protons, it will have a smaller Zeff and thus less FOA between the e⁻ and nucleus, requiring <em>less</em> energy to remove the 4s¹ e⁻.
Parrallax is used to calculate the distance.
