Acetylene gas C2H2 burns in the oxyacetylene torch for welding. How many grams of C2H2 are burned if
the reaction produces 75.0 g CO2?
2 C2H2(g) + 5 O2(g)
4 CO2(g) + 2 H2O(g)

answer; protein;

b. accuracy of the data matters alot more than its number of digits, organization or amount of detail. quantitative observation is more accepted than the qualitative observation.

your answer is a. the enthalpy of formation for a pure element in its standard state is always positive.