Iodine 131 and iodine 126 are the same in the sense that, they both have the same number of electrons and protons in their atoms, it is only the number of their neutrons that is different. Iodine 131 has 78 neutrons while iodine 126 has 73 neutrons.
<span>C7H8
First, lookup the atomic weight of all involved elements
Atomic weight of carbon = 12.0107
Atomic weight of hydrogen = 1.00794
Atomic weight of oxygen = 15.999
Then calculate the molar masses of CO2 and H2O
Molar mass CO2 = 12.0107 + 2 * 15.999 = 44.0087 g/mol
Molar mass H2O = 2 * 1.00794 + 15.999 = 18.01488 g/mol
Now calculate the number of moles of each product obtained
Note: Not interested in the absolute number of moles, just the relative ratios. So not going to get pedantic about the masses involved being mg and converting them to grams. As long as I'm using the same magnitude units in the same places for the calculations, I'm OK.
moles CO2 = 3.52 / 44.0087 = 0.079984
moles H2O = 0.822 / 18.01488 = 0.045629
Since each CO2 molecule has 1 carbon atom, I can use the same number for the relative moles of carbon. However, since each H2O molecule has 2 hydrogen atoms, I need to double that number to get the relative number of moles for hydrogen.
moles C = 0.079984
moles H = 0.045629 * 2 = 0.091258
So we have a ratio of 0.079984 : 0.091258 for carbon and hydrogen. We need to convert that to a ratio of small integers. First divide both numbers by 0.079984 (selected since it's the smallest), getting
1: 1.140953
The 1 for carbon looks good. But the 1.140953 for hydrogen isn't close to an integer. So let's multiply the ratio by 1, 2, 3, 4, ..., etc and see what each new ratio looks like (Effectively seeing what 1, 2, 3, 4, etc carbons look like)
1 ( 1 : 1.140953) = 1 : 1.140953
2 ( 1 : 1.140953) = 2 : 2.281906
3 ( 1 : 1.140953) = 3 : 3.422859
4 ( 1 : 1.140953) = 4 : 4.563812
5 ( 1 : 1.140953) = 5 : 5.704765
6 ( 1 : 1.140953) = 6 : 6.845718
7 ( 1 : 1.140953) = 7 : 7.986671
8 ( 1 : 1.140953) = 8 : 9.127624
That 7.986671 in row 7 looks extremely close to 8. I doubt I'd get much closer unless I go to extremely high integers. So it looks like the empirical formula for toluene is C7H8</span>
Answer:
The symbol of the ion is A^-
Explanation:
Let A be the symbol of the element.
Proton = 17
Electron = 18
Neutron = 20
Since the element has more electrons than protons, it means it has gain electrons.
From the question given,
The difference between the electron and proton = 18 — 17 = 1
So, the element has gain 1 electron.
Therefore the symbol of the ion is A^-
Answer:
(x + 2)(x + 2)
Explanation:
You need 2 numbers that times to give 4 and add to give 4. So 2 and 2.
Answer : The time passed in years is 
Explanation :
Half-life = 5730 years
First we have to calculate the rate constant, we use the formula :
Now we have to calculate the time passed.
Expression for rate law for first order kinetics is given by:
where,
k = rate constant = 
t = time passed by the sample = ?
a = let initial amount of the reactant = X g
a - x = amount left after decay process = 
Now put all the given values in above equation, we get
Therefore, the time passed in years is
