public void printReaction(){
  
    System.out.printf(""+molReactants.get(0).toStringf()+" + "+molReactants.get(1).toStringf()+" --> ");
    
    System.out.printf(""+molProducts.get(0).toStringf());
    for(int i=1; i< molProducts.size(); i++){
    
      System.out.printf(" + "+molProducts.get(i).toStringf());
    }
  
  
    System.out.printf("\n");
  }