Which is an example of a chemical change that occurs as part of the rock cycle? a) lava cools and condenses on the earth's surface b) sedimentary rocks are worn away by water erosion c) igneous rocks are cracked and broken into smaller pieces by weathering d) sedimentary rocks are turned into metamorphic rocks by heat and pressure

For a research project, a student decided to test the effect of the lead(ii) ion (pb2+) on the ability of salmon eggs to hatch. this ion was obtainable from the water‐soluble salt, lead(ii) nitrate, which the student decided to make by the following reaction. pbo(s) + 2 hno3(aq) → pb(no3)2(aq) + h2o losses of product for various reasons were expected, and a yield of 86.0% was expected. in order to have 5.00 g of product at this yield, how many grams of pbo should be reacted? (assume that sufficient nitric acid, hno3, would be used.)