<span>Calculating average atomic mass is exactly like calculating a weighted average. Perform the following calculation:
(mass1)(percentage1) + (mass2)(percentage2) = average atomic mass
(35.0)(0.75) + (37.0)(0.25) = average atomic mass
Make sure your percentages are in decimal form for this calculation.
One of the other answers given is correct, though the explanation is lacking a bit. Two of the answers can be eliminated immediately: 35.0 amu and 37.0 amu cannot be the average. If the mixture of isotopes was 50% and 50%, then 36.0 amu would be correct; however, the mixture is 75/25. This leaves only one possible answer choice.</span>
Sodium-22 remain : 1.13 g
<h3>Further explanation
</h3>
The atomic nucleus can experience decay into 2 particles or more due to the instability of its atomic nucleus.
Usually, radioactive elements have an unstable atomic nucleus.
General formulas used in decay:

T = duration of decay
t 1/2 = half-life
N₀ = the number of initial radioactive atoms
Nt = the number of radioactive atoms left after decaying during T time
half-life = t 1/2=2.6 years
T=15.6 years
No=72.5 g

Answer:
152 kPa = Partial pressure O₂
Explanation:
Data by percent is the molar fraction . 100.
Molar fraction of Helium = 32/ 100 → 0.32
Molar fraction of O₂ = 68/100 → 0.68
Sum of molar fractions in a mixture = 1
0.68 + 0.32 = 1
If we apply the molar fraction, we can determine the partial pressure.
Mole fraction = Partial pressure / Total pressure
0.32 = Partial pressure O₂ / 475kPa → 0.32 . 475 kPa = Partial pressure O₂
152 kPa = Partial pressure O₂
Answer:
2.114 atm
Explanation:
Since it is just pressure and volume, use Boyle's Law
P1V1 = P2V2
Then plug in numbers
(1 atm)(1 L) = P2(.473 L)
P2 = 2.114 atm
Answer:
What do you think causes some rock types to have higher densities than others? (Assuming there are no air pockets in the rock, the types of minerals will determine the density. Granite contains lots of quartz and feldspar - both fairly light minerals, whereas basalt and gabbro are made of heavier minerals.)
Explanation: