What causes high and low tides on Earth? A. The moon's gravitational pull on Earth causes water to bulge on two sides of Earth. B. Earth's rotation is so fast, water will swell and shrink twice a day. C. Earth is tilted on an axis, causing water to spread unevenly throughout the planet. D. Water swells when tsunamis occur in two areas of Earth at the same time. PLZ HELP FAST

The formation of a solid, also known as a is an indication of a chemical change. precipitate particulate particle powder

There are two steps in the usual industrial preparation of acrylic acid, the immediate precursor of several useful plastics. in the first step, calcium carbide and water react to form acetylene and calcium hydroxide: cac2 (s) + 2h2o (g) → c2h2 (g) + caoh2 (s) =δh−414.kj in the second step, acetylene, carbon dioxide and water react to form acrylic acid: 6c2h2 (g) + 3co2 (g) + 4h2o (g) → 5ch2chco2h (g) =δh132.kj calculate the net change in enthalpy for the formation of one mole of acrylic acid from calcium carbide, water and carbon dioxide from these reactions. round your answer to the nearest kj .

What does a numerical subscript following an element in a chemical formula mean?