The formula for determination of atomic mass given the mass of isotopes and relative abundance is:
Ar = ∑(mass * abundance) / 100
Ar = (68.92558 * 60.108 + 70.92470 * 39.892) / 100
Ar = 69.72306
The atomic mass of gallium is 69.72306 amu
I think the answer you have selected is right, I'm not sure tho
<span>A fast moving stream of air has a lower air pressure than a
slower air stream. As the stream of air moved over the
top of the paper, the air pressure over the paper dropped. The
air pressure underneath the paper stayed the same. The
greater air pressure underneath lifted the paper strip and it
rose. The idea that a moving air stream has lower air pressure
than air that is not moving is called “Bernoulli’s Principle”.
</span>The
force of the moving air underneath the balloon was enough to
hold it up. The weight added by the paper clip prevents
the balloon from going too high. But that is only part
of the story. The balloon stays inside the moving stream
of air because the pressure inside is the air stream is lower
than the still air around it. As the balloon moves toward the
still air outside of the air stream, the higher pressure of
the still air forces the balloon back into the lower pressure
of the air stream. Bernoulli’s Principle at work again!
The balanced equation for the above reaction is
2NaOH + H₂SO₄ ---> Na₂SO₄ + 2H₂O
stoichiometry of NaOH to H₂SO₄ is 2:1
number of NaOH moles required-0.5000 M / 1000 mL/L x 21.17 mL = 0.010585 mol
According to stoichiometry, acid moles required are 1/2 of the base moles reacted
Therefore number of H₂SO₄ moles reacted - 0.010585 /2 mol
Number of moles in 42.35 mL of H₂SO₄ - 0.010585 /2 mol
Therefore in 1 L solution - (0.010585) /2 / 42.35 mL x 1000 mL/L = 0.125 M
Molarity of H₂SO₄ - 0.125 M
