Compounds such as Freon® 112 (referred to as chlorofluorocarbons, or CFCs) were used as refrigerants for many years, but they were phased out because of their harmful effects on Earth's atmosphere. Write the molecular and empirical formulas for Freon 112. :C::C: CI: :CI: Freon 112 molecular formula: empirical formula:

When aluminum metal is heated with an element from Group 6A of the periodic table, an ionic compound forms. When the experiment is performed with an unknown Group 6A element, the product is 18.56% AI by mass. What is the formula of the compound?

Consider the following diagram, where atom X is represented by a square and atom Y is represented by a circle. (a) Write the equation for the reaction represented by the diagram. (b) If each circle stands for a mole of Y and each square a mole of X, how many moles of X did one start with? How many moles of Y? (c) Using the same representation described in part (b), how many moles of product are formed? How many moles of X and Y are left unreacted?

Many cereals are made with high moisture content so that the cereal can be formed into various shapes before it is dried. A cereal product containing 58% H2O by mass is produced at the rate of 1000. kg/h. What mass of water must be evaporated per hour if the final product contains only 20.% water?

itamin B12 , cyancobalamin, is essential for human nutrition. Its molecular formula is C63H88CoN14O14P . A lack of this vita min in the diet can lead to anemia. Cyanocohalamin is the form of the vitamin found in vitamin supplements. l type='a'> What is the molar mass of cyanocobalamin to two decimal places? How many moles of cyanocohalamin molecules are present in 250 mg of cyanocobalamin? What is the mass of 0.60 mole of cyanocobalamin? How many atoms of hydrogen are in 1 .0 mole of cyanocobalamin? What is the mass of 1.0107 molecules of cyanocobalamin? What is the mass (in grams) of one molecule of cyanocobalamin?

Hydrogen peroxide is used as a cleansing agent in the treatment of cuts and abrasions for several reasons. It is an oxidizing agent that can directly kill many microorganisms; it decomposes on contact with blood, releasing elemental oxygen gas (which inhibits the growth of anaerobic microorganisms); and it foams on contact with blood, which provides a cleansing action. In the laboratory, small quantities of hydrogen peroxide can be prepared by the action of an acid on an alkaline earth metal peroxide, such as barium peroxide: BaO2(s)+2HCl(aq)H2O2(aq)+BaCl2(aq) What mass of hydrogen peroxide should result when 1.50 g barium peroxide is treated with 25.0 mL hydrochloric acid solution containing 0.0272 g HCI per mL? What mass of which reagent is left unreacted?

Sodium borate decahydrate, Na2B4O710H2O is commonly known as borax. It is used as a deodorizer and mold inhibitor. A sample weighing 15.86 g is heated until a constant mass is obtained indicating that all the water has been evaporated off. (a) What percent, by mass of Na2B4O710H2O is water? (b) What is the mass of the anhydrous sodium borate, Na2B4O7?

What amount (moles) of compound is present in 1.00 g of each of the compounds in Exercise 52?

DDT (molar mass = 354.49 g/mol) was a widely used insecticide that was banned from use in the United States in 1973. This ban was brought about due to the persistence of DDT in many different ecosystems, leading to high accumulations of the substance in many birds of prey. The insecticide was shown to cause a thinning of egg shells, pushing many birds toward extinction. If a 20-L drum of DDT was spilled into a pond, resulting in a DDT concentration of 8.75 105 M, how long would it take for the levels of DDT to reach a concentration of 1.41 107 M (a level that is generally assumed safe in mammals)? Assume the decomposition of DDT is a first-order process with a half-life of 56.0 days.

Calcium carbonate forms carbon dioxide and calcium oxide when it is heated above 900 °C in a limekiln. When heated to 1000 °C in a laboratory, 4.31 g calcium carbonate produces 2.40 g calcium oxide and 1.90 g carbon dioxide. Outline a method similar to combustion analysis by which you could determine the empirical formula for calcium carbonate from these data. Carry out the determination.