Answer:
30, 50
Explanation:
Hello,
In this since an element's atomic number is equal to the number of protons in its atom, we can infer that selenium's atomic number is 30. Moreover, due to the fact the the neutrons are equal to the atomic mass minus the atomic number or the number of protons, by knowing the number of neutrons we compute the atomic as follows:

Thus, answer is 30, 50.
Best regards.
Answer:
a. Approximately
.
b. Approximately
.
Explanation:
The unit of concentration "
" is equivalent to "
", which means "moles per liter."
However, the volume of both solutions were given in mililiters
. Convert these volumes to liters:
.
.
In a solution of volume
where the concentration of a solute is
, there would be
(moles of) formula units of this solute.
Calculate the number of moles of
formula units in each of the two solutions:
Solution in a.:
.
Solution in b.:
.
What volume of that
(same as
)
solution would contain that many
For the solution in a.:
.
Convert the unit of that volume to milliliters:
.
Similarly, for the solution in b.:
.
Convert the unit of that volume to milliliters:
.
Answer:
Explanation:
Catalyst is I2 . Because I2 is reacted with starting material in step 1 and generated in second step
Rate limiting step is step 1. Because in rate equation CH3CHO and I2 is mentioned. Hence the overall rate of reaction is depending CH3CHO and I2. Rate limiting step is step 1
Answer to this question is C. Regarding the volume.
Answer:
0.120M is the concentration of the solution
Explanation:
<em>Assuming the mass of sodium nitrate dissolved was 2.552g</em>
<em />
Molar concentration is an unit of concentration widely used in chemsitry defined as the moles of solute (In this case NaNO3) in 1L of solution.
To find this question we must find the moles of NaNO3 in 2.552g. With this mass and the volume (250mL = 0.250L) we can find molar concentration as follows:
<em>Moles NaNO3 -Molar mass: 84.99g/mol-</em>
2.552g * (1mol / 84.99g) = 0.0300 moles NaNO3
<em>Molar concentration:</em>
0.0300 moles NaNO3 / 0.250L =
<h3>0.120M is the concentration of the solution</h3>