<span>A characteristic feature of diatom cells is that they are encased within a unique cell wall made of silica (hydrated silicon dioxide) called a frustule.</span>
I would say that you should wear a lab coat, safety goggles, and gloves
when the teacher says so - not everything in a lab is dangerous, so
there is no need to always wear these. But when the teacher says you
should - then you should.
Always use this method !!! always
A local community needs to provide more electricity for its growing population. Currently, the community's electricity needs are met by coal-burning power plants several kilometres away. Citizens are concerned that burning more coal will produce too much air pollution.
Which of the following could be used as an alternative energy resource to help minimise air pollution in this community?
A. hydroelectric energy
B. solar energy
C. wind energy
<u>D. all of these
</u>
<u />
<h3>
Answer:</h3>
2000 atoms
<h3>
Explanation:</h3>
We are given the following;
Initial number of atoms of radium-226 as 8000 atoms
Time taken for the decay 3200 years
We are required to determine the number of atoms that will remain after 3200 years.
We need to know the half life of Radium
- Half life is the time taken by a radio active material to decay by half of its initial amount.
- Half life of Radium-226 is 1600 years
- Therefore, using the formula;
Remaining amount = Original amount × 0.5^n
where n is the number of half lives
n = 3200 years ÷ 1600 years
= 2
Therefore;
Remaining amount = 8000 atoms × 0.5^2
= 8000 × 0.25
= 2000 atoms
Thus, the number of radium-226 that will remain after 3200 years is 2000 atoms.
