Answer:
The further an electron is from the nucleus. the greater its energy level.
Explanation:
When an electron is close to the nucleus, it is at as low an energy level as it can get.
We must put energy into an electron to pull it away from the attraction of a nucleus.
So, electrons that are further from the nucleus are at higher energy levels.
Mole is equal to mass of the element divided by molar mass of the element. that is
mole=mass/molar mass
From periodic table calcium has a molar mass of 40 g/mol
moles is therefore =800g/40g/mol=20moles
If not all of the salt has dissolved then the measurement of the concentration at the time is really inaccurate.
<h3>What is concentration?</h3>
The concentration is the amount of substance that is present in solution. We know that we can not measure the concentration unless all of the solute have been dissolved in the solution.
Thus, if not all of the salt has dissolved then the measurement of the concentration at the time is really inaccurate.
Learn more about concentration:brainly.com/question/10725862
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Cu ions plus EDTA2- ->cu(EDTA)2- plus 2H-
number of moles of CU ions used which is equal to molarity multiplied by volume in litres
that is 50xo.o2 divided by 1000 that is 0.001moles
Since ratio is 1:1 the moles of EDTA is also0.001moles
volume of EDTA is 0.001 divided by 0.0510m which is 0.0196 litres in ml is 0.0196x1000 which is 19.61ml
