A bear is tied to a point in the center of a large yard, so the area the bear is able to explore is circular. The chain is 20 feet long. What is the area of the region the is able to explore?

In 1901, thomas edison invented the nickel-iron battery. the following reaction takes place in the battery. fe(s) + 2 nio(oh)(s) + 2 h2o(l) fe(oh)2(s) + 2 ni(oh)2(aq) how many mole of fe(oh)2, is produced when 5.35 mol fe and 7.65 mol nio(oh) react?

You dissolve 8.65 grams of lead(l) nitrate in water and then you add 2 50 grams of aluminum. this reaction occurs 2ai(s)+ 3pb(no3)2(aq) -3pb(s)+ 2aino3la(aq) the theoretical yield of solid lead?

How can a ringing telephone can be heard through a closed door