Acetylene gas (c2h2) used in welding, pro- duces an extremely hot flame when it burns in pure oxygen according to the reaction 2 c2h2(g)+5 o2(g) −→ 4 co2(g)+2 h2o(g) . how much co2 is produced when 20000 g of c2h2 burns completely?

             67692 g of CO₂

Solution:

Balance Chemical Equation is as follow,

                            2 C₂H₂  +  5 O₂    →    4 CO₂  +  2 H₂O

According to equation,

         52 g ( 2 mole) Acetylene produces  =  176 g (4 mole) of CO₂ 
So,
              20000 g Acetylene will produce  =  X g of CO₂

Solving for X,
                          X  =  (20000 g × 176 g) ÷ 52 g

                          X  =  67692 g of CO₂

Yes, endothermic means it turns cold. and some chemical changes include change of tempature.