Solder is a silver metal used to hold pipes together. When the solder is heated, it melts and acts as a type of metal "glue." Mrs. Hanley heats a piece of solder until it melts between two pipes. What best identifies the point at which a physical change first takes place? A)when the solder melts

B)when the solder cools down

C)when the solder is a soft metal

D)when the solder becomes solid again

Aspirin has a density of 1.40 g/cm3 what is the volume in cubic centimeters of a tablet weighing 320 mg ?

Calculate the number of kilojoules to warm 125 g of iron from 23.5°c to 78.0°c.

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.