Answer:
independent variable -- different batteries
dependent variable -- the time that clock stop
Explanation:
In an experiment or a research study, there are two type of variables that can affect the result of the experiment or the conclusion. They are independent variable and the dependent variable.
An independent variable may be defined as that variable in an experiment which can be changed or can be controlled in the scientific experiment in order to test the effect on the dependent variable. It cannot be changed by other variables.
On the other hand, dependent variable are those are those which can be altered or change that can affect the experiment.
In the context, Emily uses the different types of the batteries as an independent variable and the time where the clock stopped in the dependent variable in her research.
Answer:
The increase of prey
Explanation:
Without predators in the ecosysten prey population would increase
The mass percent lithium hydroxide in the mixture with potassium hydroxide, calculated from the equivalence point in the titration of HCl with the mixture, is 19.0%.
The mass percent of lithium hydroxide can be calculated with the following equation:
(1)
Where:
(2)
We need to find the mass of LiOH.
From the titration, we can find the number of moles of the mixture since the number of moles of the acid is equal to the number of moles of the bases at the equivalence point.



Since mol = m/M, where M: is the molar mass and m is the mass, we have:
(3)
Solving equation (2) for m_{KOH} and entering into equation (3), we can find the mass of LiOH:
Solving for
, we have:

Hence, the percent lithium hydroxide is (eq 1):
Therefore, the mass percent lithium hydroxide in the mixture is 19.0%.
Learn more about mass percent here:
I hope it helps you!