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Problem- An unknown radioactive substance has a half-life of 3.20hours . If 42.6g of the substance is currently present, what mass A0 was present 8.00 hours ago?
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A 44.0 g sample of an unknown metal at 99.0 o C was placed in a constant-pressure calorimeter of negligible heat capacity containing 80.0 mL water at 24.0 o C. The final temperature of the system was found to be 28.4 ...
2KMnO 4 (s) → K 2 MnO 4 (s) + MnO 2 (s) + O 2 (g) If 2.50 L of O 2 (g) is needed at 1.00 atm and 20°C, what mass of KMnO 4 (s) should be decomposed? Assume the decomposition of KMnO 4 (s) goes to completion.
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A chemist must prepare 725. mL of 275. mM aqueous copper(II) sulfate CuSO4 working solution. He'll do this by pouring out some 0.316 M aqueous copper(II) sulfate stock solution into a graduated cylinder and diluting it w ...
A paint contains 180.0 ppm lead. Approximately what mass of lead will be in 1.00 cm ^3 of this paint when 1.00 gal is uniformly applied to 445.0 ft 2 of a wall. The density of the paint is 8.00 lb/gal.
What is the mass of NaOH present in grams, given that a 100. mL solution has a concentration of 0.125 M?
As your book describes, the United States did not recognize foreign copyrights until the late 1800s. As a result, U.S. publishers routinely published foreign works without permission or compensation for the non U.S. auth ...
A sample of CaCO 3 (s) is introduced into a sealed container of volume .654 L and heated to 1000 K until equilibrium. The reaction is . K p for the reaction is3.9*10 -2 at this temperature. Calculate the mass of CaO(s ...
This experiment involves collecting data for the cooling of water between 175 o -160. o F in different containers. What is 175 o F in celsius? Please report your answer correctly to three significant digits.
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