What you need to do is find 1/8 of 50
you can just divide 50 by 8 to get 6.25
so now you have to find how many days it will take till there are 6.25 grams of iodine left
every 8.1 days its mass is split in half
so start splitting it in half and every time you do, you add 8.1 days
50/2 =25 8.1
25/2 =12.5 + 8.1
12.5/2= 6.25 +8.1
now you have reached 1/8 of the original amount of Iodine-131
so to find how long it took just add 8.1+8.1+8.1
(this is the same as 8.1x3)
which equals 24.3
it will take 24.3 days for Iodine 131 to decay to 1/8 of its original mass.
(good luck on the regent if thats what your studying for :)
Answer:
64.0
Explanation:
2Mg+O2 ---> 2MgO
use dimentional analysis to find the amount of moles of O2 needed first
4.00molMg x 1.00mol O2/ 2.00 mol Mg=. 2.00 mol O2
using the coefficients you can see the mole ratio for O2:Mg the mole ratio is 1:2 which is why there is 1 mole on the top for 2 moles on the bottom. The Mg would cancel and multiply 4 by 1 then divide by 2, or multipy 4 by 1/2
Now that you have the moles of O2 you use the molar mass to find the grams in 2 moles of O2
2.00 mol O2 x 32.0g/1.00 mol = 64.0 g
multiply 2 by 32
The question is missing the graphics required to answer which I have attached as an image.
There are four different representations of the orientation of water molecules around chloride anion. Let's first analyze the water molecule.
We have H-O-H as the structure of water. The oxygen atom is more electronegative than the hydrogen atoms, which results in a partial positive charge on the hydrogen atoms and a partial negative charge on the oxygen atom.
The chloride anion is a negative charge. Therefore, the water molecules should orient themselves with the hydrogen atoms facing the chlorine atom as the partial positive charge on the hydrogen atoms will be attracted to the negative charge of the chlorine atom.
The correct representation is shown in graph 3 which shows all hydrogen atoms facing the chlorine anion.
The answer is (3) An electron in the third shell has more energy than an electron in the second shell. The energy of electron will increase when number of shell increase.
C. Visible light does not produce transitions between electronic energy levels in the N₂ molecule but does produce transitions in the I₂ molecule.
Explanation:
Abortion of light by molecules will produce electronic transitions from a ground level to a higher level equal to the energy of absorbed light.
In the case of nitrogen (N₂) the allowed electronic transitions are between electronic energy levels with a energy difference equal to the energy of photons of the ultraviolet light. Nitrogen will not absorb from the visible range so it is colorless.
Now iodine (I₂) have the allowed electronic transitions between electronic energy levels with a energy difference equal to the energy of photons of the visible light. As a consequence Iodine vapors have a violet color.
Learn more about:
electronic transitions
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