1. A force of 120 lbs is required to move a 45 lb bag of cat litter up a 3
ft ramp that is 2 ft off the círound.
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What does x represent in the formula for the compound xcl4?

Calculate the molar mass of aluminum oxide (al2o3). express your answer to four significant figures.

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.)