Are these physical change or chemical change? Prompt 1iron chain rusting over a long period of time

Answer for prompt 1 iron chain rusting over a long period of time

Prompt 2a piece of paper burning

Answer for prompt 2 a piece of paper burning

Prompt 3peach spoils by bacteria and rots

Answer for prompt 3

peach spoils by bacteria and rots

Prompt 4glue gun melts a glue stick

How can you use chemical equations to predict the products of the reaction you can carry out?

Lab reagent, hypothesis test.a reference solution used as a lab reagent is purported to have a concentration of 5 mg/dl. six samples are taken from this solution and the following concentrations are recorded: (5.32, 4.88, 5.10, 4.73, 5.15, 4.75) mg/dl.these six measurements are assumed to be an srs of all possible measurements from solution.they are also assumed to have a standard deviation of 0.2, a normal distributin, and a mean concentration equal to the true concentration of the solution.carry out a significance test to determine whether these six measurements provide reliable evidence that the true concentration of the solution is actually not 5 mg/dl.

What is the molar mass of the anhydrous compound? answer using four significant figures. 36.02 g/mol 120.15 g/mol 156.12 g/mol