4. Consider the side chain of the amino acids valine, aspartate, and lysine. Explain how the side chain of each molecule would change as the environment changed from pH2, to pH7, and
then pH12. Tip: think about the functional groups present and if they would be protonated/
deprotonated or charged/ not charged.
I

When water dissociates, each water molecule splits into a hydroxide ion and a) h 3 o + b) a hydrogen atom c) a hydrogen ion d) h 2 o e) oh —

Modern pennies are composed of zinc coated with copper. a student determines the mass of a penny to be 2.482 g and then makes several scratches in the copper coaling (to expose the underlying zinc). the student puts the scratched penny in hydrochloric acid, where the following reaction occurs between the zinc and the hcl (the copper remains undissolved): zn(s) + 2 hcl(aq) → h2(g) + zncl(aq)the student collects the hydrogen produced over water at 25 °c. the collected gas occupies a volume of 0.899 l at a total pressure of 79 j mmhg. calculate the percent zinc (by mass) in the penny. (assume that all the zn in the penny dissolves.)

According to le chatelier’s principle, a system in chemical equilibrium responds to stress by shifting the equilibrium in a direction that reduces the stress. normalizes the stress. increases the stress. changes the stress.