What is the molar solubility of calcium carbonate ( CaCO3 ) in water? The solubility-product constant for CaCO3 is 4.5 × 10-9 at 25 °C.
A) 8.35
B) 9.5 × 10-5
C) 9.0 × 10-9
D) 2.3 × 10-9
E) 6.7 × 10-5

Consider the equilibrium system: 2icl(s) ⇄ i2(s) + cl2(g) which of the following changes will increase the total amount of of cl2 that can be produced? all of the listed answers are correct decreasing the volume of the container removing the cl2 as it is formed adding more icl(s) removing some of the i2(s)

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.)

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