Answer:
2.05mg Fe/ g sample
Explanation:
In all chemical extractions you lose analyte. Recovery standards are a way to know how many analyte you lose.
In the problem you recover 3.5mg Fe / 1.0101g sample: <em>3.465mg Fe / g sample. </em>As real concentration of the standard is 4.0 mg / g of sample the percent of recovery extraction is:
3.465 / 4×100 = <em>86,6%</em>
As the recovery of your sample was 1.7mg Fe / 0.9582g, the Iron present in your sample is:
1.7mg Fe / 0.9582g sample× (100/86.6) = <em>2.05mg Fe / g sample</em>
<em></em>
I hope it helps!
Secondary succession occurs more rapidly than primary because soil is already available so there is no need for any other species. Also, there might still be surviving species in the soil present like seeds, roots and other plant organs.
Answer:
TRIAL 1:
For “Event 0”, put 100 pennies in a large plastic or cardboard container.
For “Event 1”, shake the container 10 times. This represents a radioactive decay event.
Open the lid. Remove all the pennies that have turned up tails. Record the number removed.
Record the number of radioactive pennies remaining.
For “Event 2”, replace the lid and repeat steps 2 to 4.
Repeat for Events 3, 4, 5 … until no pennies remain in the container.
TRIAL 2:
Repeat Trial 1, starting anew with 100 pennies.
Calculate for each event the average number of radioactive pennies that remain after shaking.
Plot the average number of radioactive pennies after shaking vs. the Event Number. Start with Event 0, when all the pennies are radioactive. Estimate the half-life — the number of events required for half of the pennies to decay.
Explanation:
Answer:
1.36x10^-19 J
Explanation:
First, we need to write the bohr's equation for the energy levels:
E(n) = -1/n² * 13.6 eV
Now, the question is asking this energy in Joules, so at the end we will use the conversion of eV to Joules.
As the energy level is 4, we just replace the value of n = 4 in the equation and solve for the energy in eV first:
E(4) = -1/4² * 13.6
E(4) = -0.85 eV
Now, the conversion for eV to Joules is the following:
1 eV = 1.6022x10^-19 J
Therefore, we just need to multiply the obtained value of Energy in eV with this factor, and we have the energy in Joules as required:
E = -0.85 * 1.6022x10^-19
E = 1.36x10^-19 J
This is the energy in Joules for an electron in the level 4.
The answer would be both, because the physical change is liquid to gases, and the chemical change is the molecules being split into hydrogen and oxygen molecules.