What is the minimum amount of heat required to completely melt 20.0 grams of ice at its melting point?
(1) 20.0 j (3) 6680 j
(2) 83.6 j (4) 45 200 j

Identify the lewis acid in this balanced equation: ag+ + 2nh3 -> ag(nh3)2+a. ag+b. nh3c. ag(nh3)2+

State one important difference between a physical change and a chemical change?

Choose all the answers that apply. fluorine (f) has an atomic number of 9 and an atomic weight of 18.99. fluorine has a. 9 protons b. 10 neutrons c. 18 electrons d. an atomic mass of 19 e. at least one isotope