Aqueous lead nitrare is combined with aqueous potassium chromate to form soild lead chromate and potassim nitrate is solution. If 25.0 grams of each recant is used, what is the percent yield of lead chromate if 20.0 grams of PbCrO4 is collected ? K2CrO4 + Pb(NO3)2 - 2KNO3 answer choices
58.8%
66.6%
69.0%
81.5%

Long term exposure to waves can cause sunburns and skin cancer. a) visible b) infrared c) gamma rays d) ultraviole

Which of the following is a physical change? a.burning a piece of wood b.sawing a piece of wood in half c.rust forming on an iron fence d.a copper roof changing color from orange to green

Which best describes the present-day universe? opaque, expanding very slowly, stars produce heavy elements transparent, expanding at an accelerated rate, stars produce heavy elements opaque, expanding at an accelerated rate, stars produce only hydrogen and helium transparent, expanding very slowly, stars produce only hydrogen and helium