Slow chemical change
It is a chemical change because the erosion is due to the chemical reaction between the acid and the in the rain and the calcium carbonate.
It is slow due to the concentration of acid is low.
The answer will be A & B not only because it makes sense but evaporation is taking water away not adding to (gaining)
Making repeated separations of the various substances in the pitchblende, Marie and Pierre used the Curie electrometer to identify the most radioactive fractions. They thus discovered that two fractions, one containing mostly bismuth and the other containing mostly barium, were strongly radioactive.
<h3>What was surprising about pitchblende?</h3>
Since it was no longer appropriate to call them “uranic rays,” Marie proposed a new name: “radioactivity.”
Even more surprising, Marie next found that a uranium ore called pitchblende contained two powerfully radioactive new elements: polonium, which she named for her native Poland, and radium.
<h3>Why is radium more radioactive than uranium?</h3>
It is 2.7 million times more radioactive than the same molar amount of natural uranium (mostly uranium-238), due to its proportionally shorter half-life.
Learn more about highly radioactive elements here:
<h3>
brainly.com/question/10257016</h3><h3 /><h3>#SPJ4</h3>
I believe the answer is a
Answer:
8.20 % → Percent yield reaction
Explanation:
To find the percent yield of reaction we apply this:
(Produced yield / Theoretical yield) . 100 = %
Produced yield = 112.9 g
Theoretical yield = 1375.5 g
We replace → (112.9g / 1375.5 g) . 100
8.20 % → Percent yield reaction
