AP CollegeBoard AP Chemistry
Test Booklet
Unit 9 Review

2X(g) + Y(g) = 3Z(g)
The reaction mixture represented above is at equilibrium at 298 K, and the molar concentrations
are [X] - 2.0 M. [= 0.5 M, and [2] = 4.0 M. What is the value of the equilibrium constant for the
reaction at 298 K ?
0.50
2.0
4.0
16
32
I

answer; i do believe the correct answer is (river); /// good luck

given:

mass of na = 115 g

excess cl2

to determine:

mass of nacl produced

explanation:

given reaction is-

2na(s) + cl2(g) → 2nacl(s)

since cl2 is in excess, na will be the limiting reagent

as per the reaction stoichiometry na: nacl = 1: 1

i.e. moles of na reacted = moles of nacl formed

now, # moles of na = mass of na/atomic mass

                                  = 115 g/23 g.mol-1 = 5 moles

therefore, moles of nacl = 5

molar mass of nacl = 58 g/mol

mass of nacl = 5 moles * 58 g.mol-1 = 290 g

ans: amount of nacl produced = 290 g

i do not get it   at all

it's c (engineer's do their work with mechanical stuff not on any living being)