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;

18.5 seconds

explanation;

velocity is distance covered per unit time; it is given by displacement divided by time.

thus; time = displacement/velocity

total time = total displacement/velocity

total distance = 5000 meters south

total time = 5000/4.5

                  = 1111.11 seconds

but; 1 minute = 60 sec

thus; 1111.11 /60

                = 18.51 seconds

thus; the time taken is 18.5 seconds