A compound is found to have a composition of 54.092% Ca, 43.187% O, and 2.721% H. What is the empirical formula of the compound?

Which of the following true? a_volcanoes and earthquakes often near the plate boundaries. b_volcanoes occur whereve there are tall mountains. c_earthquakes cause volcanoes in the same location to erupt violently d_volcanoes and earthquakes occur only where plates are colliding with each other

What reaction is taking place? 02 + c3h8 = h20 + co2

Use examples from the article to explain one positive and one negative effect that chemistry has had on society.