You need to use Stoichiometry
This is a simple algebraic problem, specifically for the mixture type of problem. Let x be the mass of 40% solution and y be the mass of 70% solution. The first equation would then be:
x + y = 20 --> eqn 1
The second equation would be the mass balance shown below:
(x)(0.40) + y(0.70) = 20(0.52) --> eqn 2
Rearranging eqn 1,
x = 20 - y
Substitute this to eqn 2:
(20 - y)(0.40) + y(0.70) = 20(0.52)
Solve for y,
y = 8 grams
Finally, solve for x.
x = 20 - 8 = 12 grams
<em>Therefore, Serena needs 12 grams of the 40% solution and 8 grams of the 70% solution.</em>
Answer:
5000 and 
indicate that there is more B than A at equilibrium
Explanation:
For the given reaction: ![K=\frac{[B]}{[A]}](https://tex.z-dn.net/?f=K%3D%5Cfrac%7B%5BB%5D%7D%7B%5BA%5D%7D)
where [B] and [A] represents equilibrium concentration B and A respectively. K represents equilibrium constant
More B than A at equilibrium means, [B] > [A]
So, ![K=\frac{[B]}{[A]}>1](https://tex.z-dn.net/?f=K%3D%5Cfrac%7B%5BB%5D%7D%7B%5BA%5D%7D%3E1)
As, both 5000 and are greater than 1 therefore these two K values indicate that there is more B than A at equilibrium
From shortest wavelength to longest wavelength: ultraviolet ,visible light ,infrared
