Is silver tarnishing a chemical or physical change?

How does a hydroelectric power plant converts energy into energy.

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 mass of 2.00 l of an intravenous glucose solution with a density of 1.15 g/ml?