Is a fireplace poker glowing red when placed into fire a chemical or physical change

What is the partial pressure of ethane, pethane, in the flask?

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.)

Five different substances are given to you to be dissolved in water. which substances are most likely to undergo dissolution in water? check all that apply. view available hint(s) check all that apply. sodium fluoride, naf octane, c8h18 propanol, ch3ch2ch2oh potassium iodide, ki benzene, c6h6