An atom of strontium-90 contains how many electrons, protons, and neutrons?
38e⁻, 38 protons, and 52 neutrons
Answer: subduction and sea floor spreading
Explanation:
He knew that the continents today were once joined together by fossil records of plants and animals that were found to be on continents far removed from each other. He knew this also by corresponding land forms that matches up as well. What he couldn’t prove is how the land masses would have moved so far away from each other. Subduction and sea floor spreading move the tectonic plates that the continents sit on. That’s what he was missing.
Answer:
0.01185M = moles/0.02755L
0.02755*0.01185=0.00032647
Explanation:
sorry i don't know the answer i'm really sorry
Answer:
pH = 1.32
Explanation:
H₂M + KOH ------------------------ HM⁻ + H₂O + K⁺
This problem involves a weak diprotic acid which we can solve by realizing they amount to buffer solutions. In the first deprotonation if all the acid is not consumed we will have an equilibrium of a wak acid and its weak conjugate base. Lets see:
So first calculate the moles reacted and produced:
n H₂M = 0.864 g/mol x 1 mol/ 116.072 g = 0.074 mol H₂M
54 mL x 1L / 1000 mL x 0. 0.276 moles/L = 0.015 mol KOH
it is clear that the maleic acid will not be completely consumed, hence treat it as an equilibrium problem of a buffer solution.
moles H₂M left = 0.074 - 0.015 = 0.059
moles HM⁻ produced = 0.015
Using the Henderson - Hasselbach equation to solve for pH:
ph = pKₐ + log ( HM⁻/ HA) = 1.92 + log ( 0.015 / 0.059) = 1.325
Notes: In the HH equation we used the moles of the species since the volume is the same and they will cancel out in the quotient.
For polyprotic acids the second or third deprotonation contribution to the pH when there is still unreacted acid ( Maleic in this case) unreacted.
