The much of the sample that would remain unchanged after 140 seconds is 2.813 g
Explanation
Half life is time taken for the quantity to reduce to half its original value.
if the half life for Scandium is 35 sec, then the number of half life in 140 seconds
=140 sec/ 35 s = 4 half life
Therefore 45 g after first half life = 45 x1/2 =22.5 g
22.5 g after second half life = 22.5 x 1/2 =11.25 g
11.25 g after third half life = 11.25 x 1/2 = 5.625 g
5.625 after fourth half life = 5.625 x 1/2 = 2.813
therefore 2.813 g of Scandium 47 remains unchanged.
All the following are equal to Avogadro's number EXCEPT a. the number of atoms of bromine in 1 mol Br₂.
1 mol Br₂ contains Avogadro’s number of molecules of Br₂.
However, each molecule contains two atoms of Br, so there are
<em>2 × Avogadro’s number of Br atoms </em>in 1 mol Br₂.
Answer:
<h2>0.93 g/mL</h2>
Explanation:
The density of a substance can be found by using the formula
From the question
mass = 37.2 g
volume = 40 mL
We have
We have the final answer as
<h3>0.93 g/mL</h3>
Hope this helps you
varying composition is not a property of a pure substance
