What isotope has mass of 204 and 124 neutrons?

Needthe meter is the standard unit for: 1) height 2) length 3) weight 4) mass

Classify this reaction: 2al+n2-> aln.

Amixture initially contains a, b, and c in the following concentrations: [a] = 0.300 m , [b] = 1.05 m , and [c] = 0.550 m . the following reaction occurs and equilibrium is established: a+2b⇌c at equilibrium, [a] = 0.140 m and [c] = 0.710 m . calculate the value of the equilibrium constant, kc.