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
It’s x200 plus 300 that’s why it is that answer
Answer:
1
Explanation:
An unknown element, X, is a nonmetal that contains seven valence electrons. Element X most likely forms <u>1 </u>covalent bond.
Nonmetals gain the electron to complete the octet and form anion. Consider the example of halogen.
When it combine with another halogen atom they form covalent bond. There are seven valance electrons in outer most orbital of halogen atom. By combining with other halogen atom they form one covalent bond and complete the octet.
For example:
Cl atom combine with other Cl atom and form Cl₂.
I think the two are text and pictorial.
