Answer: A basis or standard for evaluation, assessment, or comparison; a criterion.
something that is used to judge or understand something else Definition of point of reference. : something that is used to judge or understand something else The professor used the study as a point of reference for evaluating and discussing other theories.
Explanation:
The scale of most metal characteristics goes from the bottom left-hand corner.
The least metallic is the top right-hand.
So then that means that
Calcium-YES, second column
Germanium-No, to far, in the middle
Arsenic-Non-metal,
Bromine, same for this
Calcium
The density of air surrounding the balloon may be calculated by assuming that air is an ideal gas and using the equation,
PV = nRT
In terms of density,
density = PM/RT
Using the given data,
density = (1 atm)(28.84 g/mol)/(0.0821 L.atm/molK)(20+273K) = 1.20 g/L
Using ratio and proportion,
density of balloon = 0.577 g/ V = 1.20 g/L
The volume is equal to 0.48 L.
Since the half-life is 4.5 billion years, two half-lives would have elapsed after 9 billion years.
<span>If you start with 400 g, half decays during the first half-life, leaving 200 g. </span>
<span>During the second half-life, half of the 200 g decays, leaving 100 g.</span>
