Answer:
20.53 g.
Explanation:
- Knowing that every 15.0 g of pure calcium fluoride contains 7.70 g of calcium.
<u>Using cross multiplication:</u>
15.0 g of pure calcium fluoride contains → 7.70 g of calcium.
40.0 g of pure calcium fluoride contains → ??? g of calcium.
<em>∴ The mass of Ca in 40.0 g of calcium fluoride</em> = (7.70 g)(40.0 g)/(15.0 g) = <em>20.53 g.</em>
Answer:

Explanation:
Hello!
In this case, since the given reaction is:

Whereas the equilibrium constant is:
![K=\frac{[C][D]^{5/2}}{[A][B]^2} =4.0](https://tex.z-dn.net/?f=K%3D%5Cfrac%7B%5BC%5D%5BD%5D%5E%7B5%2F2%7D%7D%7B%5BA%5D%5BB%5D%5E2%7D%20%3D4.0)
However, the new target reaction reverses and doubles the initial reaction to obtain:

Whereas the equilibrium constant is:
![K'=\frac{[A]^2[B]^4}{[C]^2[D]^5}](https://tex.z-dn.net/?f=K%27%3D%5Cfrac%7B%5BA%5D%5E2%5BB%5D%5E4%7D%7B%5BC%5D%5E2%5BD%5D%5E5%7D)
Which suggest the following relationship between the equilibrium constants:

So we plug in to obtain:

Best regards!
I have done this question before and even though you didn’t provide the options. I think the correct option is elements
It is the 3rd option. Theories must be substantiated by a large amount of evidence and previous research