Explain how a cold compress used by athletes is an endothermic or exothermic
reaction.

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How many liters of water vapor can be produced if 108 grams of methane gas (ch4) are combusted at 312 k and 0.98 atm? show all work. pls ! will mark as brainliest

Part 1: include important facts found through your research. part 2: include your visual display. include your summary of “the chemistry of water” from the national science foundation website. include your experiment. part 3: include responses to the reflection questions.

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.)