Question 3: Empirical and Molecular Formula (1 point) a. What is the difference between the empirical formula and the molecular formula? (.5 point)

b. How does one determine the molecular formula from the empirical formula? (.5 point)

Question 4: Percent Composition (3.5 points)

a. How is the percent composition by mass determined? (.5 point)

b. Determine the percent composition of each element in MgCl2. (1 point)

i. Magnesium (Mg): (.5 point)

ii. Chlorine (Cl): (.5 point)

c. Calculate the empirical formula from the given percent compositions.
82% nitrogen (N), 18% hydrogen (H) (2 points)

Atrain travels 74 kilometers in 3 hours, and then 81 kilometers in 5 hours. what is its average speed?

The table compares the number of electrons in two unknown neutral atoms. comparison of electrons atom number of electrons a 9 d 11 use this information to determine the number of valence electrons in the atoms. which of the following correctly compares the stability of tthe table compares the number of electrons in two unknown neutral atoms. comparison of electrons atom number of electrons a 9 d 11 use this information to determine the number of valence electrons in the atoms. which of the following correctly compares the stability of the two atoms? both are unreactive. both are highly reactive. a is unreactive and d is reactive. a is reactive and d is unreactive.

If 3 moles of a compound use 24 j of energy in a reaction, what is the a hreaction in j/mol?