I think the answer is:
B. Chemical Change.
I think it’s C atomic radius and numbers of unshielded protons
Get a majority of the world to go green
Ca + 2HCl = CaCl₂ + H₂
c=4.50 mol/l
v=2.20 l
n(HCl)=cv
m(Ca)/M(Ca)=n(HCl)/2
m(Ca)=M(Ca)cv/2
m(Ca)=40g/mol·4.50mol/l·2.20l/2=198 g
198 grams of Ca are needed
Answer:
You manage to find a bottle of bromothymol blue and a few extra beakers. You take one of the empty beakers and add some of the first unlabeled solution and some indicator.
The color changes to yellow.
You then add some solution from the other unlabeled flask into this beaker and see the color change to blue.
What are the identities of each unlabeled solution?
Explanation:
Bromothymol blue is a dye and it is used as an indicator.
It is used as a pH indicator.
In acids, it becomes yellow n in color.
In bases, it turns blue.
You take one of the empty beakers and add some of the first unlabeled solution and some indicator. The color changes to yellow.
That means the unlabeled solution is an acid.
You then add some solution from the other unlabeled flask into this beaker and see the color change to blue.
It is a basic solution.
