Which structure is a valid representation of a hydrocarbon molecule?

What is the relation between concentration of reactants and the rate of chemical reaction?

Which of the following contributes to the structural rigidity of cellulose? adjacent glucose polymers are stabilized by hydrogen bonding. glucose residues are joined by (α1→4) linkages. cellulose is a highly branched molecule. the conformation of the glucose polymer is a coiled structure.

What is the most common reason for matter changing its state?