Consider three 1L flask at STP. Flask A contains NH3, flask B contains NO2 gas and flask C contain N2 gas. Which constains the largest number of molecules?

Answer : All flask contains the same number of molecules.

Explanation :

As we know that at STP,

Pressure of flask = 1 atm

Temperature of flask = 273 K

Volume of flask = 1 L

The given molecules are,

Every molecule contains equal number of molecules that is, 1.

That means all the value of variables are same. Thus, all flask contains the same number of molecules.

Hence, all flask contains the same number of molecules.

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

that tool would be a compass