Can someone please help me? I am so lost. John Dalton made the following claim: "Atoms of different elements vary in size and mass." Refer back to any of the periodic tables to support this claim with reasoning and evidence.

Often on a topographic map, every fifth contour line is darkened. what is this line called? a. key b.slope c.benchmark d. index contour

Astudent is trying to create a table that compares hypotheses, theories, and laws. hypothesis theory law do scientific researchers formulate it? yes yes yes does it explain why things happen? yes yes no yes yes yes is it used to make predictions? no yes yes which of the following questions would most likely fill the blank in the table? is it an intelligent guess? is it newly formulated? is it based on observations? has it been proved?

Areaction is first order with respect to reactant x and second order with respect to reactant y. which statement describes the rate law for this reaction?