. A compound with an empirical formula of C20H4 and a molar mass of 88 grams per mole. What is the molecular formula of this compound? A. C.O2H12 . A compound with an empirical formula of CaH«O and a molar mass of 136 grams per mole. What is the molecular formula of this compound? A. CeHeO2 B. C.OAH10 C. C2O2H6 D. C.O2He B. C&H&O4 C. C2H2O2 D. CioH1804

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?

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

4.9 Sulfur, S8, combines with oxygen at elevated temperatures to form sulfur dioxide. (a) Write a balanced chemical equation for this reaction. (b) If 200 oxygen molecules are used up in this reaction, how many sulfur molecules react? (c) How many sulfur dioxide molecules are formed in part (b)?

Bacterial digestion is an economical method of sewage treatment. The reaction is an intermediate step in the conversion of the nitrogen in organic compounds into nitrate ions. What mass of bacterial tissue is produced in a treatment plant for every 1.0 104 kg of wastewater containing 3.0% NH4+ ions by mass? Assume that 95% of the ammonium ions are consumed by the bacteria.

Small amounts of tungsten (W) are usually added to steel to strengthen and harden the steel. Two ores of tungsten are ferberite (FeWO4) and scheelite (CaWO4). How many grams of FeWO4 would contain the same mass of tungsten that is present in 725 g of CaWO4?

3.120 1f you have 32.6 g of sodium carbonate that is dissolved to give 2.10 L of solution, what is the molarity of the solution? What is the molarity of the sodium ions?

A large family of boron-hydrogen compounds has the general formula BxHy. One member of this family contains 88.5% B; the remainder is hydrogen. What is its empirical formula?

3.109 Materials engineers often create new alloys in an effort to improve the properties of an existing material. ZnO based semiconductors show promise in applications like light-emitting diodes, but their performance can be enhanced by the addition of small amounts of cadmium. One material that has been studied can he represented by the formula Zn0.843Cd0.157O. (These materials are solid solutions, and so they can have variable compositions. The noninteger coefficients do not imply fractional atoms.) Express the composition of this alloy in terms of (a) at%, (b) mol%, and (c) wt%.

3.75 The following pictures show a molecular-scale view of a chemical reaction between the compounds AB2 and B2. (A atoms are shown in blue and B atoms in white). The box on the left represents the reactants at the instant of mixing, and the box on the right shows what is left once the reac- tion has gone to completion. Write a balanced chemical equation for this reaction. As usual, your equation should use the smallest possible whole number coefficients for all substances.