1 answer:
Answer:
Explanation:
Half life of Nobelium-253 is 97 seconds . That means after every 97 seconds half of the Nobelium amount will be disintegrated .
Time taken in bringing the sample to laboratory = 291 seconds
291 second = 291 / 97 half life
n = 3
N =
N₀ is original mass , N is mass after n number of half life.
N = 5 mg x
= .625 mg
Only 0.625 mg of Nobelium-253 will be left .
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1.51 x 10²⁵atoms
Explanation:
Given parameters:
Mass of Na = 578g
Unknown:
Number of atoms = ?
Solution:
To find the number of atoms, we must first find the number of moles the given mass contains.
Number of moles =
molar mass of Na = 23g
Number of moles = = 25.13moles
1 mole of a substance = 6.02 x 10²³atoms
25.13 mole of Na = 25.13 x 6.02 x 10²³atoms
This gives 1.51 x 10²⁵atoms of Na
Learn more:
Avogadro's constant brainly.com/question/2746374
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<h2>Question:- </h2>
A solution has a pH of 5.4, the determination of [H+].
<h2>Given :- </h2>- pH:- 5.4
- pH = - log[H+]
Take negative to other side
-pH = log H+
multiple Antilog on both side
(Antilog and log cancel each other )
Antilog (-pH) = [ H+ ]
New Formula :- Antilog (-pH) = [+H]
Now put the values of pH in new formula
Antilog (-5.4) = [+H]
we can write -5.4 as (-6+0.6) just to solve Antilog
Antilog ( -6+0.6 ) = [+H]
Antilog (-6) × Antilog (0.6) = [+H]
put the value in equation