Which of the following is NOT a characteristic of a compound?

What mass of natural gas (ch4) must you burn to emit 276 kj of heat?

Pl what kind of reaction is this? nahco3 + h2o → co2 + naoh + h2o -composition -decomposition -single replacement -double replacement im leaning more toward single replacement. if im wrong can you explain whyy?

The element chlorine has two stable isotopes, chlorine-35 with a mass of 34.97 amu and chlorine-37 with a mass of 36.95 amu. from the atomic weight of cl = 35.45 one can conclude that: