Calculate the number of atoms of hydrogen (H) in 323 cm3 of the colorless gas ethylene at 0 °C and atmospheric pressure, where its density is 1.25×10-3 g cm-3. The molecular formula of ethylene is C2H4.

3.117 For the oxides of iron, FeO, Fe2O3, and Fe3O4, describe how you would determine which has the greatest percentage by mass of oxygen. Would you need to look up any information to solve this problem?

Nitrogen fixation in the root nodules of peas and other legumes occurs with a reaction involving a molybdenum-containing enzyme named nitrogenase. This enzyme contains two Mo atoms per molecule and is 0.0872% Mo by mass. Calculate the molar mass of the enzyme.

4-102 Aspartame, an artificial sweetener used as a sugar substitute in some foods and beverages, has the molecular formula C14H18N2O5. (a) How many mg of aspartame are present in 3.72 × 1026 molecules of aspartame? (b) Imagine you obtain 25.0 mL of aspartame, which is known to have a density of 1.35 g/mL. How many molecules of aspartame are present in this volume? (c) How many hydrogen atoms are present in 1.00 mg of aspartame? (d) Complete the skeletal structure of aspartame, where all the bonded atoms are shown but double bonds, triple bonds, and/or lone pairs are missing. (e) Identify the various types of geometries present in each central atom of aspartame using VSEPR theory. (f) Determine the various relative bond angles associated with each central atom of aspartame using VSEPR theory. (g) What is the most polar bond in aspartame? (h) Would you predict aspartame to be polar or nonpolar? (i) Is aspartame expected to possess resonance? Explain why or why not. (j) Consider the combustion of aspartame, which results in formation of NO2(g) as well as other expected products. Write a balanced chemical equation for this reaction. (k) Calculate the weight of C02(g) that can be prepared from 1.62 g of aspartame mixed with 2.11 g of oxygen gas.

4.69 The pictures below show a molecular-scale view of a chemical reaction between H2 and CO to produce methanol, CH3OH. 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 reaction has gone to completion. Was there a limiting reactant in this reaction? If so, what was it? Write a balanced chemical equation for this reaction. As usual, your equation should use the smallest possible whole number coefficients for all substances.

The present average concentration (mass percent) of magnesium ions in seawater is 0.13%. A chemistry textbook estimates that if 1.00 × 108 tons Mg were taken out of the sea each year, it would take one million years for the Mg concentration to drop to 0.12%. Do sufficient calculations to either verify or refute this statement. Assume that Earth is a sphere with a diameter of 8000 mi, 67% of which is covered by oceans to a depth of 1 mi, and that no Mg is washed back into the oceans at any time.

Boron forms an extensive series of compounds with hydrogen, all with the general formula BxHy. To analyze one of these compounds, you burn it in air and isolate the boron in the form of B2O3 and the hydrogen in the form of water. You find that 0.1482 g BxHy gives 0.4221 g B2O3 when burned in excess O2. Determine the empirical I formula of BxHy.

Calculate the number of atoms of carbon (C) in 475 cm3 of the colorless gas butane at 0 °C and atmospheric pressure, where its density is 2.59×10-3 g cm-3. The molecular formula of butane is C4H10.

What is the value of x? Express your answer as an integer.

Consider the Haber-Bosch process for the synthesis of ammonia from its elements. Calculate the theoretical yield in moles in NH3 from the complete reaction of 15.6 g H2 in the presence of excess N2 gas according to the following balance chemical equations: N2(g) + 3 H2(g) > 2 NH3(g)