With work shown. 7. Calculate the number of sodium atoms in 4.66 moles of sodium
ID: 1051606 • Letter: W
Question
With work shown.
7. Calculate the number of sodium atoms in 4.66 moles of sodium.
8. What is the molar mass fo a substance if 0.6502 moles of the substance has a mass of 19.27 grams?
9. How many grams are present in 7.5 moles of Cu (NO3)2?
10. How many atoms are present in a Mg sample with a mass of 14.6 grams?
11. How many atoms of H are present in 37.6 g of NH3?
12. How many atoms are present in 0.45 moles of P4O10?
13. The empirical formula of a compound is CH2O and it's formula weight is 120.12 amu. What is the molecular formula?
14. Analysis of an unknown sample indicated the sample contained 0.140g of N and 0.320 g of O. The molar mass of the compound was determined to be 92.02 amu. What is the molecular formula of the compound?
Explanation / Answer
7. no of sodium atoms = no of moles * 6.023*1023
= 4.66*6.023*1023
= 2.806*1024 atoms
8. molar mass = mass of substance/no of moles
= 19.27/0.6502 = 29.64 g/mole
9. mass of Cu(NO3)2 = no of moles* gram molar mass
= 7.5*187.56 = 1406.7g
10. no of magnesium atoms = W*6.023*1023/G.A.Wt
= 14.6*6.023*1023 /24
= 3.7*1023 atoms
11. no of hydrogen atoms = W*6.023*1023 * atomicity of hydrogen/G.M.Wt
= 14.6*6.023*1023*3 /17
=1.55*1024 hydrogen atoms
12. no of atoms = no of moles * 6.023*1023 * atomicity
= 0.45*6.023*1023 *14
= 3.794*1024 atoms
13. molecular formula = (empirical formula)n
n = M.F.wt/E.F.Wt
= 120.12/30 = 4
molecular formula = (CH2O)4 = C4H8O4
Related Questions
drjack9650@gmail.com
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.