<span>Ca has 2 valence electrons and F has 7, they would end up having to share electrons but Ca or F has to keep one because in total there are 9 valence elections and only 8 are needed to make this pair "happy". that's all i can provide. i hope it helped some</span>
The reaction equation is:
<span>2CuO(s) + C(s) </span>→ <span>2Cu(s) + CO</span>₂<span>(g)
First, we determine the number of grams present in one ton of copper oxide. This is:
1 ton = 9.09 x 10</span>⁵ g
We convert this into moles by dividing by the molecular mass of copper oxide, which is:
9.09 x 10⁵ / 79.5 = 11,434 moles
Each mole of carbon reduces two moles of copper oxide, so the moles of carbon required are:
11,434 / 2 = 5,717 moles of Carbon required
The mass of carbon is then:
5,717 x 12 = 68,604 grams
The mass of coke is:
68,604 / 0.95 = 72,214 g
The mass of coke required is 7.22 x 10⁴ grams
Explanation:
the pH of the solution defined as negatuve logarithm of 
ion concentration.
![pH=-\log[H^+]](https://tex.z-dn.net/?f=pH%3D-%5Clog%5BH%5E%2B%5D)
1. Hydrogen ion concentration when pH of the solution is 11.
![11=-\log[H^+]](https://tex.z-dn.net/?f=11%3D-%5Clog%5BH%5E%2B%5D)
![[H^+]=1\times 10^{-11} mol/L](https://tex.z-dn.net/?f=%5BH%5E%2B%5D%3D1%5Ctimes%2010%5E%7B-11%7D%20mol%2FL)
..(1)
At pH = 11, the concentration of ions is 
.
2. Hydrogen ion concentration when the pH of the solution is 6.
![6=-\log[H^+]'](https://tex.z-dn.net/?f=6%3D-%5Clog%5BH%5E%2B%5D%27)
![[H^+]'=1\times 10^{-6} mol/L](https://tex.z-dn.net/?f=%5BH%5E%2B%5D%27%3D1%5Ctimes%2010%5E%7B-6%7D%20mol%2FL)
..(2)
At pH = 6, the concentration of ions is 
.
3. On dividing (1) by (2).
![\frac{[H^+]}{[H^+]'}=\frac{1\times 10^{-11} mol/L}{1\times 10^{-6} mol/L}=1\times 10^{-5}](https://tex.z-dn.net/?f=%5Cfrac%7B%5BH%5E%2B%5D%7D%7B%5BH%5E%2B%5D%27%7D%3D%5Cfrac%7B1%5Ctimes%2010%5E%7B-11%7D%20mol%2FL%7D%7B1%5Ctimes%2010%5E%7B-6%7D%20mol%2FL%7D%3D1%5Ctimes%2010%5E%7B-5%7D%20)
The ratio of hydrogen ions in solution of pH equal to 11 to the solution of pH equal to 6 is 
.
4. Difference between the ions at both pH:
This means that Hydrogen ions in a solution at pH = 7 has 
ions fewer than in a solution at a pH = 6
Answer:
answer is b
Explanation:
I think it is b. I don't know what land lenses are but focusing light on the can would heat it up more.
