Answer:
A simple displacement reaction occurs when an iron nail is immersed to a beaker containing copper sulphate solution.
a)
Iron is more reactive than copper. As a result a displacement reaction will take place. The ferrous or Fe (II) irons will move to the solution. The copper ions (Cu II) will get deposited on the nail. This will cause the colour to change from blue to green.
b)
The equation can be written as:
Fe (s) + CuSO4 (aq) -> FeSO4 (aq) + Cu (s)
c)
A chemical change can be described as a change that causes a substance to change to another form. Hence, this reaction is a chemical change.
Answer:
The correct answer is: pH= 4.70
Explanation:
We use the <em>Henderson-Hasselbach equation</em> in order to calculate the pH of a buffer solution:
![pH= pKa + log \frac{ [conjugate base]}{[acid]}](https://tex.z-dn.net/?f=pH%3D%20pKa%20%2B%20log%20%20%20%5Cfrac%7B%20%5Bconjugate%20base%5D%7D%7B%5Bacid%5D%7D)
Given:
pKa= 4.90
[conjugate base]= 4.75 mol
[acid]= 7.50 mol
We calculate pH as follows:
pH = 4.90 + log (4.75 mol/7.50 mol) = 4.90 + (-0.20) = 4.70
Answer:
Adding a solution containing an anion that forms an insoluble salt with only one of the metal ions.
Explanation:
The student have in solution Ag⁺ and Cu²⁺ ions but he just want to analyze the silver, that means he need to separate ions.
Centrifuging the solution to isolate the heavier ions <em>FALSE </em>Centrifugation allows the separation of a suspension but Ag⁺ and Cu²⁺ are both soluble in water.
Adding enough base solution to bring the pH up to 7.0 <em>FALSE </em>At pH = 7,0 these ions are soluble in water and its separation will not be possible.
Adding a solution containing an anion that forms an insoluble salt with only one of the metal ions <em>TRUE </em>For example, the addition of Cl⁻ will precipitate the Ag⁺ as AgCl(s) allowing its separation.
Evaporating the solution to recover the dissolved nitrates. <em>FALSE</em> . Thus, you will obtain the nitrates of these ions but will be mixed doing impossible its separation.
I hope it helps!
Remember this:
atomic mass= atomic number + number of neutrons
The atomic number (same thing as number of protons) in this case is 15. The atomic mass is 31.
So, we subtract 15 from 31 to find the number of neutrons.
31-15=16
16 neutrons!!!
No the maximum number of electrons for "4p" is 6 so there can't be a 4p7
