Group 1 cations precipitate easily in a relatively high concentration of hydrochloric acid. After the separation from the other group 1 cations, the presence of lead can be tested by addition of potassium chromate. Explain what is wrong with the given equation for this test. Pb(aq) + CrO4(aq) <-> PbCrO(aq)

Although respiratory organs vary across different organisms, they all contain respiratory surfaces that have a large surface area and are extremely thin. explain why having an extremely thin respiratory surface with a large surface area is advantageous for the process of gas exchange

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.)

How does the value of the equilibrium constant show that a reaction reaches equilibrium very quickly? (a) the equilibrium constant is large. (b) the equilibrium constant is small. (c) the equilibrium constant is zero. (d) the value of the equilibrium constant does not show how quickly a reaction comes to equilibrium.