<span>a) 7.9x10^9
b) 1.5x10^9
c) 3.9x10^4
To determine what percentage of an isotope remains after a given length of time, you can use the formula
p = 2^(-x)
where
p = percentage remaining
x = number of half lives expired.
The number of half lives expired is simply
x = t/h
where
x = number of half lives expired
t = time spent
h = length of half life.
So the overall formula becomes
p = 2^(-t/h)
And since we're starting with 1.1x10^10 atoms, we can simply multiply that by the percentage. So, the answers rounding to 2 significant figures are:
a) 1.1x10^10 * 2^(-5/10.5) = 1.1x10^10 * 0.718873349 = 7.9x10^9
b) 1.1x10^10 * 2^(-30/10.5) = 1.1x10^10 * 0.138011189 = 1.5x10^9
c) 1.1x10^10 * 2^(-190/10.5) = 1.1x10^10 * 3.57101x10^-6 = 3.9x10^4</span>
Answer:
radiation, conduction, convection, conduction
A mixture
having a uniform composition where the components can't be seen separately and
all components are in the same state best describes a solution.
<span>In chemistry, a </span>solution<span> is a
homogeneous mixture composed of two or more substances. In such a mixture, a
solute is a substance dissolved in another substance, known as a solvent.</span>
The correct answer between all
the choices given is the third choice or letter C. I am hoping that this answer
has satisfied your query and it will be able to help you in your endeavor, and
if you would like, feel free to ask another question.
A measure of thermal energy transferred between two different bodies at different temperatures would be the correct answer. So, the third option.
