How many moles are equivalent to 2.50x1020 atoms of fe?

Aglow stick contains a glass vial with chemicals. when the glow stick is bent, the vial breaks and the chemicals react to produce a glow. a science student observes that a glow stick kept in the freezer glows for a longer duration than a glow stick kept at room temperature. what conclusion can be drawn based on the observation? be sure to note the outcome and test variables in the conclusion.

Aconcentrated solution of ammonia is 14.8m and has a density of 0.899g/l. what is the concentration of ammonia in this solution in weight percent (%w/w)?

Consider the heating curve of h2o and line segments a, b, and c. several changes are taking place at a, b, and c. all but one would be an appropriate description as e move through segments a, b and then c.