Answer:
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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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We suggest starting to prep for the the SAT as early as eighth grade year. It sound early, but if a student plans on taking the SAT several times throughout high school, eighth graders can take a relaxed and long-view approach to prepping, and can plan on taking their first SAT sophomore year.
The suggested number of sleep hours for teens is between 8 to 10 hours daily.
<h3>
Sleeping hours of teens</h3>
This is the estimated time in which teens are expected to sleep or have full rest.
The average estimated time of sleep hours for teens is between 8 to 10 hours. This may vary according to health condition of individuals.
Thus, the suggested number of sleep hours for teens is between 8 to 10 hours daily.
Learn more about sleeping time here: brainly.com/question/20555693
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