Is concrete a homogenous or heterogenous mixture?

How many liters of oxygen gas, at standard temperature and pressure, will react with 35.8 grams of iron metal? 4 fe (s) + 3 o₂ (g) → 2 fe₂o₃ (s)

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

An unsaturated hydrocarbon is a hydrogen-carbon compound with a. a network solid structure b. single bonds c. single bonds in a branched-chain structure d. double or triple bonds