Atomic mass is the mass of a chemical element expressed in atomic mass units. Molar mass the mass of a given substance divided by its amount of substance in (mol) .
Answer:<span> a) the process for the first ionization energy
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<span>Every time you take a electron you're requiring more and more energy. Expelling the first one
will require less energy than expelling the second and the second will
require less than the third, and so on.
When you take the first one, the atom becomes positive and with that the negative forces of the electron will be more attracted to the positive
charge. The more electrons that are lost, the
more positive this ion will become, causing it to be more difficult to separate the
electrons from the atom.
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most events like the rising and setting of the Sun were used a natural measurement of time until recently.
Solar time, which is based on the motion of the Sun, is not the only way of measuring time, however. One might keep track of the regular appearance of the full Moon. That event occurs once about every 29.5 solar days. The time between appearances of new moons, then, could be used to define a month.
One also can use the position of the stars for measuring time. The system is the same as that used for the Sun, since the Sun itself is a star. All other stars also rise and set on a regular basis.
Although any one of these systems is a satisfactory method for measuring some unit of time, such as a day or a month, the systems may conflict with each other. It is not possible, for example, to fit 365 solar days into 12 or 13 lunar months exactly. This problem creates the need for leap years
Read more: http://www.scienceclarified.com/Ti-Vi/Time.html#ixzz5e1E705sr
I abbreviated most of it but there is a ton more at this link if you still need more.
Answer: The concentration of unknown sample is 1.8 mg/ml
Explanation:
According to the dilution law,
where,
= concentration of stock solution = ?
= volume of stock solution = 0.25 ml
= concentration of diluted solution = 0.45 mg/ml
= volume of diluted solution = (0.25+0.75) ml = 1.00 ml
Putting in the values we get:
Therefore, concentration of unknown sample is 1.8 mg/ml
