Answer:
The concentration the student should write down in her lab is 2.2 mol/L
Explanation:
Atomic mass of the elements are:
Na: 22.989 u
S: 32.065 u
O: 15.999 u
Molar mass of sodium thiosulfate, Na2S2O3 = (2*22.989 + 2*32.065 + 3*15.999) g/mol = 158.105 g/mol.
Mass of Na2S2O3 taken = (19.440 - 2.2) g = 17.240 g.
For mole(s) of Na2S2O3 = (mass taken)/(molar mass)
= (17.240 g)/(158.105 g/mol) = 0.1090 mole.
Volume of the solution = 50.29 mL = (50.29 mL)*(1 L)/(1000 mL)
= 0.05029 L.
To find the molar concentration of the sodium thiosulfate solution prepared we use the formula:
= (moles of sodium thiosulfate)/(volume of solution in L)
= (0.1090 mole)/(0.05029 L)
= 2.1674 mol/L
Answer:
Lewis structure of polyatomic formate anion.
Explanation:
To draw Lewis structure for any chemical species,
1)Count the total number of valence electrons present in it.
This can be obtained by adding valence electrons of each constituent atom.
2)Arrange those valence electrons in such a way that each atom should attain eight electrons around it to satisfy octet theory.
The structure of formate ion and its Lewis structure are shown below:
HCOO- is the formate ion.
It has total:
1+4+6+6+1 = 18 valence electrons.
Since, hydrogen has one, carbon has four and oxygen has six valence electrons and the charge of the anion is one.
Arrange this 18 electrons in such a way that each atom should get 8 electrons around it.
Resonance structures of formate ion:
Detrivores; i.e, Earth Worms, Rolly Pollies etc.
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