When a substance cannot be reduced by physical or chemical means to a simpler form, it is an example of a(n):

mixture

molecule

element

compound

Amixture that has two or more substances that are spread out evenly is called a. compound b. heterogeneous c. substance d. homogeneous

Ascientist conducted an experiment and discovered that certain plants grow faster when given a particular amount of fertilizer. anouther scientist conducted the same experiment and got similar results. which concept does this best illustrate? a) repetition b) replication c) precision d) validity

In a laboratory determination of the atomic weight of tin, a sample of tin is weighed in a crucible. nitric acid is added, and the reaction proceeds to give a hydrated tin(iv)oxide plus no2and h2o. the hydrated tin(iv)oxide is then heated strongly and reacts as follows: sno2.xh2o(s)sno2(s)+ xh2o(g)the sno2is finally cooled and weighed in the crucible. explain the effect on the calculated atomic weight of tin that would result from each of the following experimental errors: (a)considerable spattering occurs when the nitric acid is added to the tin.(b)the hydrated tin(iv)oxide is not heated sufficiently to change it completely to tin oxide.