Doubt about implementation of N: N relationship using C #

I'm having to make a relationship between N: N classes but storing objects in memory, follows the following relationship:

Imadetheimplementationasfollowsandwouldliketoknowifitiscorrectornot.

  

ChemicalClass

publicclassChemical{publicintID{get;set;}publicstringChemicalName{get;set;}publicstringChemicalFormula{get;set;}publicDecimalMW{get;set;}publicintVFId{get;set;}//Visual_Flow_IDpublicBooleanProjectChemical{get;set;}publicChemical(){}

  

StreamClass

publicclassStream{publicintID{get;set;}publicstringName{get;set;}publicvirtualIList<StreamComposition>Chemicals{get;set;}publicStream(){this.Chemicals=newList<StreamComposition>();}publicvoidAddChemical(StreamCompositionsc){this.Chemicals.Add(sc);Console.WriteLine("Adding Chemical: " + sc.Chemical.ChemicalName + 
                    " to the Stream: => " + sc.Stream.Name + "\n");
            }
        }

  

StreamComposition class

public class StreamComposition
{
    public virtual Stream Stream { get; set; }

    public virtual Chemical Chemical { get; set; }

    public Decimal MolePerCent { get; set; }

    public StreamComposition()
    {
    }
}

Populating objects

Creating Stream

Stream Stream1 = new Stream() { ID = 1, Name = "SHD4", };

Creation of the 3 objects 'Chemicals'

Chemical ch1 = new Chemical() // Criando uma 'Chemical'
                {
                    ID = 1,
                    ChemicalName = "Hidrogenio",
                    ChemicalFormula = "H",
                    MW = 2,
                    VFId = 2,
                    ProjectChemical = true
                };

Chemical ch2 = new Chemical() // Criando outra 'Chemical'
            {
                ID = 2,
                ChemicalName = "Ferro",
                ChemicalFormula = "Fe",
                MW = 4,
                VFId = 8,
                ProjectChemical = false,
            };

Chemical ch3 = new Chemical()
            {
                ID = 3,
                ChemicalName = "Agua",
                ChemicalFormula = "H20",
                MW = 9,
                VFId = 10,
                ProjectChemical = true,
            }; 

Creating the 3 associative classes

StreamComposition sc1 = new StreamComposition() // Criando StreamComposition
            {
                Stream = Stream1,
                Chemical = ch1,
                MolePerCent = 4.0m,
            };

StreamComposition sc2 = new StreamComposition() // Criando StreamComposition
            {
                Stream = Stream1,
                Chemical = ch2,
                MolePerCent = 8.0m,
            };

StreamComposition sc3 = new StreamComposition() // Criando StreamComposition
            {
                Stream = Stream1,
                Chemical = ch3,
                MolePerCent = 8.0m,
            };

Assigning the Chemicals Created for the Stream 'Stream1'

            Stream1.AddChemical(sc1);
            Stream1.AddChemical(sc2);
            Stream1.AddChemical(sc3);