Use the following chemical equation to answer the question. 4K(s) + O2(g) → 2 K2O(s)

If a staff member at a laboratory has 12.0 grams of potassium metal, what mass of potassium oxide could the scientist potentially produce from the reaction with oxygen gas?

Express the following number in scientific notation. 0.026890 =

What are the first three quantum numbers for the electrons located in subshell 2s?

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.)