Answer:
2.68
Explanation:
At the solution, the number of moles of each substance (acid and conjugate base) is the volume multiplied the concentration
nHNO₂ = 0.50 L * 0.85 mol/L = 0.425 mol
nNO₂⁻ = 0.50 L * 0.61 mol/L = 0.305 mol
At the buffer, the substances are in equilibrium. When HBr is added, it dissociantes in H⁺ and Br⁻, and the H⁺ will react with NO₂⁻ to form more HNO₂. So, NO₂⁻ will be consumed and HNO₂ will be formed at a 1:1:1 reaction:
nH⁺ = nHBr = 0.15 mol
nNO₂⁻ = 0.305 - 0.15 = 0.155 mol
nHNO₂ = 0.425 + 0.15 = 0.575 mol
The pH of a buffer can be calculated by the Handerson-Halsebach equation:
pH = pKa + log[A⁻]/[HA]
Where [A⁻] is the concentration of the conjugate base, and [HA], the concentration of the acid. Because the volume is the same, it can be used the number of moles:
pH = 3.25 + log (0.155/0.575)
pH = 2.68
The answer is b, because solid water is less dense than liquid water and that is why it floats. This property of water is due to hydrogen bonds between the water molecules because <span>in ice, the regular pattern of hydrogen bonds pushes the molecules further apart leaving a lot of empty space between the water molecules. </span>
Answer: here u go i hope this hlpe
Answer:
A. is the correct answer because Boron has 3 electrons too,
All elements in Group 13 have three electrons in their outermost energy level. The two most popular elements in this group are Boron and Aluminum.