☃️ Chemical formulae ➝ 
How to find?
For solving this question, We need to know how to find moles of solution or any substance if a certain weight is given.
Solution:
❍ Molecular weight of
= 2 × 126.90
= 253.80
= 254 (approx.)
❍ Given weight: 12.7
Then, no. of moles,
⇛ No. of moles = 12.7 / 254
⇛ No. of moles = 0.05 moles
⚘ No. of moles of Iodine molecule in the given weight = <u>0.05</u><u> </u><u>moles </u>
<u>━━━━━━━━━━━━━━━━━━━━</u>
The total mass would be 142.05 g/mol. Since sodium is 22.99 g/mol and there are 2 sodium atoms, it would be 45.98 g/mol. Divide 45.98 by 142.05 and you get 32.37%
given days = 42 days
So, number of half life, n = 42/14.3 = 2.93
So, after 42 days, the mass of sodium phosphate sample left = original mass
x (1/2)^n,
= 157 mg x (1/2)^2.93 = 20.60 g of Na3PO4 after 42 days
Formula mass of Sodium phosphate = 3(23) + 32 + 4(16) amu = 165 amu
165 g of sodium phosphate contains 32 g of Phosphorus
20.60 g ------------------------------? = 20.60 x 32/ 165 =3.99g of P32
The image<span> formed by a plane </span>mirror<span> is always virtual (meaning that the light rays </span>do<span> not actually come from the </span>image<span>), upright, and of the same shape and size as the object it is reflecting. A virtual </span>image<span> is a copy of an object formed at the location from which the light rays </span>appear<span> to come.</span>
the conversion would be 0.00225 mole
