Answer:
Average of measurements = 20.97 cm
Explanation:
Given data:
Three measurements of pete's = 20.9 cm, 21.0 cm, 21.0 cm.
Average value of measurements = ?
Formula:
Average of measurements = sum of all measurements / Total number of measurements
Solution:
Average of measurements = 20.9 cm + 21.0 cm + 21.0 cm. / 3
Average of measurements = 62.9 cm / 3
Average of measurements = 20.97 cm
Ionic compounds are formed between oppositely charged ions.
A binary ionic compound is composed of ions of two different elements - one of which is a positive ion(metal), and the other is negative ion (nonmetal).
To write the empirical formula of binary ionic compound we must remember that one ion should be positive and other ion should be negative, then only the correct formula should be written. To write the empirical formula the charges of opposite ions should be criss-crossed.
First empirical formula of binary ionic compound is written between![Zn^{2+} (Positive ion)and F^{-} (Negative ion)](https://tex.z-dn.net/?f=%20Zn%5E%7B2%2B%7D%20%28Positive%20ion%29and%20F%5E%7B-%7D%20%28Negative%20ion%29)
First Formula would be ![ZnF_{2}](https://tex.z-dn.net/?f=%20ZnF_%7B2%7D%20)
Second empirical formula is between ![Zn^{2+}(Positive ion) and O^{2-}(Negative ion)](https://tex.z-dn.net/?f=Zn%5E%7B2%2B%7D%28Positive%20ion%29%20and%20O%5E%7B2-%7D%28Negative%20ion%29)
Second Formula would be ![Zn_{2}O_{2}](https://tex.z-dn.net/?f=Zn_%7B2%7DO_%7B2%7D)
Note : When the subscript are same they get cancel out, so
would be written as ![ZnO](https://tex.z-dn.net/?f=ZnO)
Third empirical formula is between ![Ni^{4+}(Positive ion) and F^{-}(Negative ion)](https://tex.z-dn.net/?f=Ni%5E%7B4%2B%7D%28Positive%20ion%29%20and%20F%5E%7B-%7D%28Negative%20ion%29)
Third Formula would be :![NiF_{4}](https://tex.z-dn.net/?f=NiF_%7B4%7D)
Forth empirical formula is between ![Ni^{4+}(Positive ion)and O^{2-}(negative ion)](https://tex.z-dn.net/?f=Ni%5E%7B4%2B%7D%28Positive%20ion%29and%20O%5E%7B2-%7D%28negative%20ion%29)
Forth Formula would be :
or ![NiO_{2}](https://tex.z-dn.net/?f=NiO_%7B2%7D)
Note- The subscript will be simplified and the formula will be written as
.
The empirical formula of four binary ionic compounds are : ![ZnF_{2}, ZnO, NiF_{4},NiO_{2}](https://tex.z-dn.net/?f=ZnF_%7B2%7D%2C%20ZnO%2C%20NiF_%7B4%7D%2CNiO_%7B2%7D)