Considering the definition of percentage by mass, the sample of pure lithium nitrate contains 7.99% lithium by mass.
<h3>Definition of percentage by mass</h3>
The percentage by mass expresses the concentration and indicates the amount of mass of solute present in 100 grams of solution.
In other words, the percentage by mass of a component of the solution is defined as the ratio of the mass of the solute to the mass of the solution, expressed as a percentage.
The percentage by mass is calculated as the mass of the solute divided by the mass of the solution, the result of which is multiplied by 100 to give a percentage. This is:

<h3>This case</h3>
Because percent by mass indicates the ratio of solute to solution based on mass, if the sample has twice the mass of the first sample, the ratio remains constant.
So the percentage by mass is the same.
That is, the sample of pure lithium nitrate contains 7.99% lithium by mass.
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Learn more about percent by mass:
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Pain in the fingers, wrists, or other parts of the body: may include a dull aching pain, a sharp stabbing pain, or even a burning sensation
The rule used to translate the image is
.
In this question we are going to speak of point translations. Vectorially speaking, a translation between two points is defined by this expression:
(1)
Where:
- Original point.
- Translation vector.
- Translated point.
If we know that
and
, then the translation vector is:



Therefore, the rule used to translate the image is
.
We kindly invite to see this question on translations: brainly.com/question/17485121