A chemist test new mixtures for paint samples and decides one mixtuees stickiness makes is worthless

Which class of molecules functions as chemical signals? hormones water carbohydrates proteins

100 grams of molten lead (600°c) is used to make musket balls. if the lead shot is allowed to cool to room temperature (21°c), what is the change in entropy (in j/k) of the lead? (for the specific heat of molten and solid lead use 1.29 j/g⋅°c; the latent heat of fusion and the melting point of lead are 2.45 × 104 j/kg and 327°c, respectively.)

Which is an example of a reversible physical change?