Which statement below describes a physical property of a substance? A. Helium gas floats because is less air dense than air

B. Sulfuric acid is a toxic liquid

C. Iron rusts when exposed to water and air

D. Sodium metal explodes when exposed to water

Achemist has dissolved a certain substance in water. the chemist knows that more of the substance could be dissolved into the water before it stops dissolving. therefore

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 many atoms are in 2 moles of phosphorus