Why is the separation of mixtures into pure or relatively pure substances so important when performing a chemical analysis?

In performing horizontal analysis, why is it important to look at both the amount and the percentage change?

Geneticists often carry out reciprocal crosses when they are studying the inheritance of traits. Why do geneticists use reciprocal crosses?

When performing a molecular evolution experiment, why is it important to repeat the selection and replication steps for several generations?

In the fruit fly Drosophila melanogaster, very dark (ebony) body color is determined by the e allele. The $e^{+}$ allele produces the normal wild-type, honey-colored body. In heterozygotes for the two alleles, a dark marking called the trident can be seen on the thorax, but otherwise the body is honey-colored. The $e^{+}$ allele is thus considered to be incompletely dominant to the e allele. a. When female $e^{+} e^{+}$ flies are crossed to male $e^{+} e$ flies, what is the probability that progeny will have the dark trident marking? b. Animals with the trident marking mate among themselves. Of 300 progeny, how many would be expected to have a trident, how many ebony bodies, and how many honey-colored bodies?

Explain why an acid-base indicator changes color over a range of pH values rather than at a specific pH.

Why are actual yields usually less than calculated theoretical yields?

Why do real gases not always behave ideally? Under what conditions does a real gas behave most ideally? Why?

Why are the tin(IV) halides more volatile than the tin(II) halides?

Why are the tin(IV) halides more volatile than the tin(II) halides?

What special property of the noble gases makes them unreactive? The boiling points and melting points of the noble gases increase steadily from He to Xe. Explain. The noble gases were among the last elements discovered; their existence was not predicted by Mendeleev when he published his first periodic table. Explain. In chemistry textbooks written before 1962, the noble gases were referred to as the inert gases. Why do we no longer use this term? For the structures of the xenon compounds in the figure, give the bond angles exhibited and the hybridization of the central atom in each compound.

What is wrong with the following statement? “The results of the experiment do not agree with the theory. Something must be wrong with the experiment.”

On which temperature scale $(^{o}\text{F}, ^{o}\text{C}$, or $\text{K})$ does 1 degree represent the smallest change in temperature?

What is the difference between $\mathscr { G }$ and $\mathscr { G } ^ { \circ } ?$ When is $\mathscr { G }$ equal to zero? When is $\mathscr { G } ^ { \circ }$ equal to zero? (Consider "regular" galvanic cells as well as concentration cells.)