It should be 0.25 M. Use the formula C1*V1=C2*V2, for those values, as it is right when it changed colour. Remember to change the if those are not the same (but in your case it is, so no need this time).
C1*V1=C2*V2
C1*27ml=0.55M*12.5ml
C1=(0.55M*12.5ml)/27ml = 0.25M
Answer:
No, it's a physical reaction.
Explanation:
A chemical change produces new chemical compounds, but combining water and powder is just mixing the powder with the water. It's not a new compound.
I don't know how to really explain, sorry :)
The answer which would have been a major difference in the ocean basins is the following one:
<span>B. Mid-ocean ridges would have been chains of mountains.
Given that the waters were lower in the past, those ridges would no longer be just mid-ocean ridges, but complete mountains due to the low levels of water around them.</span>