Matching 19. Molds and Casts 20. Freezing
21. Imprint
22. Petrification
23. Amber

a. remains turn to solid rock
b. shows space once occupied by organism
c. often preserves entire insect bodies
d. can show things like foot prints
e. preserves entire animals (Wooly Mammoth)

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

in the analysis of systems that involve fluid flow, we frequently encounter the combination of properties u and pv.

you need to stop taking that class