Final answer:
The mixture of hydrogen and carbon monoxide produced by heating natural gas with steam is called water gas.
Step-by-step explanation:
The mixture of hydrogen and carbon monoxide produced by heating natural gas with steam is called water gas. This reaction involves passing steam over coke (an impure form of elemental carbon) at high temperatures, typically around 1000 °C. The balanced equation for this reaction is: C(s) + H₂O(g) → CO(g) + H₂(g).