Exam 3: Stoichiometry: Mass, Formulas, and Reactions

The combustion of ethanol (CH₃CH₂OH, 46.1 g/mol) results in the formation of water and carbon dioxide. How many grams of carbon dioxide are produced when 46.1 g of ethanol burns?

Which statement about a balanced chemical reaction equation is always correct?

A compound was analyzed and found to contain 25.24% S and 74.76% F. What is the empirical formula for the molecular compound?

Baking soda (NaHCO₃, 84.0 g/mol) requires acids from other ingredients to generate the carbon dioxide needed to make bread rise. The following equation describes this reaction, where HB is some unspecified acid. If 20.4 g of baking soda are used in a recipe and enough acid is present for a complete reaction, how many moles of carbon dioxide are generated? HB NaHCO₃ H₂O CO₂ NaB

In one analysis, the density of ozone in an air sample was found to be 5.00 10^-8 mol/L. What is the density in molecules per liter?

Write the balanced reaction equation for the decomposition of ammonium nitrate into nitrogen gas, oxygen gas, and water vapor.

Diborane undergoes combustion according to the following unbalanced reaction. B₂H₆ O₂ HBO₂ H₂O Balance the equation and calculate how much HBO₂ can be formed from 12.6 g of B₂H₆?

Which statement about the following chemical reaction is not correct? 2H₂ O₂ 2H₂ O₂

The most abundant metal in Earth's crust is aluminum, found mostly in the form of clays. There are no economical routes for extracting aluminum from clay. However, bauxite ore, impure hydrated aluminum oxide, is found in hot, humid regions, such as Australia, Guinea, and Brazil, and it can be purified and refined to make the metal. After the first purification step, hydrated aluminum oxide (Al₂O₃ . xH₂O) is obtained. When 100.0 g of this solid were heated, and the water driven off, 65.36 g of Al₂O₃ remained. How many water molecules (x in the molecular formula) were there in the hydrate?

A gallon of water has a mass of 3.79 kg. How many moles of water (18.02 g/mol) is this?

Household bleach contains 5.0% sodium hypochlorite (NaOCl) by mass. Household ammonia contains 5.0% NH₃ by mass. If 50.00 g of bleach are mixed with 50.00 g of 5.0% ammonia, what mass of the toxic chloramine gas would be produced by the following reaction? NaOCl NH₃ NH₂Cl NaOH

A hydrocarbon molecule contains carbon and hydrogen atoms in equal numbers. Its molar mass is 130.18 g/mol. What is the molecular formula for the hydrocarbon?

A fuel cell works on the same principle as a battery but is continually fed with fuel. In one fuel cell, methanol (CH₃OH) enters on one side of the unit and air enters on the other side. Both circulate past electrodes, and a chemical reaction occurs that produces electricity, plus carbon dioxide and water as byproducts. Which balanced chemical reaction equation best represents the reaction that occurs in this fuel cell?

Why is the term formula unit more appropriate for an ionic compound such as sodium chloride, NaCl, than the term molecular formula?

Metallic sodium was originally produced by the Deville process, where sodium carbonate and carbon black are heated to 1100 ^$\circ$ C to produce sodium (as a liquid at that temperature) and carbon monoxide gas, according to the following balanced equation. Na₂CO₃(s) 2C(s) 2Na(l) 3CO(g) If 2.3 kg of sodium carbonate is heated, what is the maximum amount of sodium that can be produced?

The average adult exhales about 1.0 kg of carbon dioxide each day. How much oxygen is needed in metabolizing glucose (C₆H₁₂O₆, 180 g/mol) to make that much carbon dioxide?

Which statement A-D regarding the carbon cycle is not correct?

What are the stoichiometric coefficients for oxygen and water, respectively, in the balanced chemical reaction equation representing the combustion of butane (C₄H₁₀)?

Baking ammonia or ammonium bicarbonate (NH₄HCO₃, 79.1 g/mol) is a leavening agent used in some older recipes. As it is heated, it breaks down into three gases: ammonia, water, and carbon dioxide. For each 20 g of baking ammonia heated (about 4 tsp), how many grams of carbon dioxide are produced?

Hydrogen peroxide decomposes to produce water and oxygen. Which relationship regarding the quantities of reactants and products associated with this reaction is not correct? 2H₂O₂ $\to$ 2H₂O + O₂