Carbon molar mass

Polarity Parameter. Despite their appareat simplicity, these parameters, ( ), show a good correlatioa with plasticizer activity for nonpolymeric plasticizers (10). The parameter is defiaed 2ls (j) = [M A j Po)]/1000 where M = molar mass of plasticizer, = number of carboa atoms ia the plasticizer excluding aromatic and carboxyHc acid carbon atoms, and Pg — number of polar (eg, carbonyl) groups present. The 1000 factor is used to produce values of convenient magnitude. Polarity parameters provide useful predictions of the activity of monomeric plasticizers, but are not able to compare activity of plasticizers from different families. 

Dimefoylhydrazine, foe fuel used in foe Apollo lunar descent module, has a molar mass of 60.10 g/mol. It is made up of carbon, hydrogen, and nitrogen atoms. The combustion of 2.859 g of the fuel in excess oxygen yields 4.190 g of carbon dioxide and 3.428 g of water. What are foe simplest and molecular formulas for dimefoylhydrazine ... 

Many of these salts melt or sublime before or during decomposition and reaction temperatures generally increase with molar mass. Thermal analyses for a selection of ammonium carboxylates have been given by Erdey et al. [915] who conclude that the base strength of the anion increases with temperature until it reaches that of NH3. Decompositions of ammonium acetate (>333 K) and ammonium oxalate (>473 K) proceed through amide formation. Ammonium benzoate and ammonium salicylate sublime (>373 K) without decomposition but ammonium citrate decomposes (>423 K) to yield some residual carbon. 

Note-. Bisphenol-A and the diaryl esters of terephthalic acid and isophthalic acid are nonvolatile compounds, so that any excess of these components cannot completely be removed, resulting in a low-molar-mass, unusable polyester. Moreover, excess bisphenol-A causes a strong discoloration of the polyester melt due to thermal degradation at the high reaction temperature used. This can be avoided if the diaryl esters are mixed with 5 mol% of diphenyl carbonate. Any excess of this compound can easily be removed in vacuum at the polycondensation temperature. 

E.29 The king of Zirconia is naturally fond of the element zirconium and has established an independent definition of the mole based on zirconium. The mass of one zirconium-90 atom is 1.4929 X 10 22 g. If zirconium were the standard used for molar mass (instead of carbon-12), 1 mol would be defined as the amount of substance that contains the same number of entities as there are atoms in exactly 90 g of zirconium-90. In that case, what would be (a) the molar mass of carbon-12 (b) the (average) molar mass of gold ... 

SOLUTION We consider a sample of exactly 100 g, then convert the masses into I amounts in moles by dividing the mass percentage for each element by the element s molar mass. The mass of carbon in a sample of vitamin C of mass 100 g is 40.9 g. Because the molar mass of carbon is 12.01 g-moD1,... 

F.13 Osmium forms a number of molecular compounds with carbon monoxide. One light-vellow compound was analyzed to give the following elemental composition 15.89% C, 21.18% O, and 62.93% Os. (a) What is the empirical formula of this compound (b) From the mass spectrum of the compound, the molecule was determined to have a molar mass of 907 g-mol 1. What is its molecular formula ... 

Self-Test L.2B Carbon dioxide can be removed from power plant exhaust gases by combining it with an aqueous slurry of calcium silicate 2 C02(g) + H,0(l) + CaSiOds) — Si02(s) + Ca(HC03)2(aq). What mass of CaSiO, (having molar mass 116.17 g-mol ) is needed to react completely with 0.300 kg of carbon dioxide ... 

M.3 Polychlorinated biphenyls (PCBs) were once widely used industrial chemicals but were found to pose a risk to health and the environment. PCBs contain only carbon, hydrogen, and chlorine. Aroclor 1254 is a PCB with molar mass 360.88 g-mol. Combustion of 1.52 g of Aroclor 1254 produced 2.224 g of CO, and combustion of 2.53 g produced 0.2530 g of H20. How many chlorine atoms does an Aroclor 1254 molecule contain ... 

M.9 The stimulant in coffee and tea is caffeine, a substance of molar mass 194 g-mol When 0.376 g of caffeine was burned, 0.682 g of carbon dioxide, 0.174 g of water, and 0.1 10 g of nitrogen were formed. Determine the empirical and molecular formulas of caffeine, and write the equation for its combustion. 

M.10 Nicotine, the stimulant in tobacco, causes a very complex set of physiological effects in the body. It is known to have a molar mass of 162 g-mol. When a sample of mass 0.385 g was burned, 1.072 g of carbon dioxide, 0.307 g of water, and 0.068 g of nitrogen were produced. What are the empirical and molecular formulas of nicotine Write the equation for its combustion. 

Eleven elements are gases under normal conditions (Fig. 4.2). So are many compounds with low molar masses, such as carbon dioxide, hydrogen chloride, and organic compounds such as the methane, CH4, of natural gas and the... 

The addition of 0.24 g of sulfur to 100. g of the solvent carbon tetrachloride lowers the solvent s freezing point by 0.28°C. What is the molar mass and molecular formula of sulfur ... 

An elemental analysis of epinephrine resulted in the following composition 59.0% carbon, 26.2% oxygen, 7.15% hydrogen, and 7.65% nitrogen by mass. When 0.64 g of epinephrine was dissolved in 36.0 g of benzene, the freezing point decreased by 0.50°C. (a) Determine the empirical formula of epinephrine, (b) What is the molar mass of epinephrine ... 

The mass of an atom in terms of the atomic mass constant is numerically the same as the molar mass in grams per mole. For instance, the molar mass of carbon-12 is exactly 12 g-mol, and the mass of a carbon-12 atom is exactly 12mu. 

A hydrocarbon is 90% carbon by mass and 10% hydrogen by mass and has a molar mass of 40 g-mol It decolorizes bromine water, and 1.46 g of the hydrocarbon reacts with 1.60 L of hydrogen (measured at STP) in the presence of a nickel catalyst. Write the molecular formula of the hydrocarbon and the structural formulas of two possible isomers. 

If the sample consists of atoms of one element, the mass spectrum gives the isotopic distribution of the sample. The relative molar masses of the isotopes can be determined by comparison with atoms of carbon-12. If the sample is a compound, the formula and structure of the compound can be determined by studying the fragments. For example, the + 1 ions that CH4 could produce are CH4, CH3+, CH, CFI4, C+, and H4. Some of the particles that strike the detector are those that result when the molecule simply loses an electron (for example, to produce Cl I4+ from methane) ... 

The molar enthalpy of combustion increases with molar mass as might be expected, because the number of moles of CO, and H,0 formed will increase as the number of carbon and hydrogen atoms in the compounds increases. The heat released per gram of these hydrocarbons is essentially the same because the H to C ratio is similar in the three hydrocarbons. 

Unlike the case with dilute solutions of polymer, the variation of the melt viscosity and molar mass is far from completely understood. However, the melt viscosity, has been found to vary uniformly with number of carbon atoms in the chain above about 300-500, according to the equation ... 

The molar mass (MM) of any substance is the mass of one mole of that substance. As described in Section 2-1. each isotope of a particular element has a different mass. Therefore, the mass of one mole of any isotope has a unique value, its isotopic moiar mass. This characteristic molar mass can be found by multiplying the mass of one atom of that isotope by Avogadro s number. For example, mass spectrometry experiments reveal that one atom of carbon-13 has a mass of 2.15928 X 10- g, from which we can calculate the isotopic molar mass of... 

Analysis of ibuprofen, the active ingredient in several over-the-counter pain relievers, shows that it contains 75.7% carbon, 8.8% hydrogen, and 15.5% oxygen. The mass spectrum of ibuprofen shows that its molar mass is less than 210 g/mol. Determine the chemical formula of this compound. 

You can verify that Cg Hig has a molar mass of 114 g/mol. This compound, containing only carbon and hydrogen, is an example of a hydrocarbon. Its name is octane, from the eight carbon atoms in the molecule. Gasoline Is known to contain hydrocarbons, so this is a reasonable result. 

C03-0071. Calculate the molar mass of each of the following substances (a) carbon tetrachloride (b)... 

C03-0089. Combustion analysis of 0.60 g of an unknown organic compound that contained only C, H, and O gave 1.466 g of carbon dioxide and 0.60 g of water in a combustion analysis. Mass spectral analysis showed that the compound had a molar mass around 220 g/mol. Determine the empirical formula and molecular formula. 

C05-0071. Freons (CFCs) are compounds that contain carbon, chlorine, and fluorine in various proportions. They are used as foaming agents, propellants, and refrigeration fluids. Freons are controversial because of the damage they do to the ozone layer in the stratosphere. A 2.55-g sample of a particular Freon in a 1.50-L bulb at 25.0 °C has a pressure of 262 torr. What is the molar mass and formula of the compound ... 

C05-0072. Gaseous hydrocarbons, which contain only carbon and hydrogen, are good fuels because they bum in air to generate large amounts of heat. A sample of hydrocarbon with m— 1.65 g exerts a pressure of 1.50 atm in a 945-mL bulb at 21.5 °C. Determine the molar mass and chemical formula of this hydrocarbon. 

C12-0071. An aqueous solution contains 1.00 g/L of a derivative of the detergent lauryl alcohol. The osmotic pressure of this solution at 25.0 °C is measured to be 64.8 torr. (a) What is the molar mass of the detergent (b) The hydrocarbon portion of the molecule is an 11-carbon chain. What is the molar mass of the polar portion ... 

C13-0003. Draw one complete specific line structure for each of the following (a) an amine with the formula Cg Hi 5 N (b) an ester with at least seven carbon atoms (c) an alcohol with a molar mass of 74 g/mol and (d) a molecule with at least ten carbons that contains an aldehyde group and a phenyl ring... 

Figure 7.7b shows the essential features of a refinery catalytic cracker. Large molar mass hydrocarbon molecules are made to crack into smaller hydrocarbon molecules in the presence of a solid catalyst. The liquid hydrocarbon feed is atomized as it enters the catalytic cracking reactor and is mixed with the catalyst particles being carried by a flow of steam or light hydrocarbon gas. The mixture is carried up the riser and the reaction is essentially complete at the top of the riser. However, the reaction is accompanied by the deposition of carbon (coke) on the surface of the catalyst. The catalyst is separated from the gaseous products at the top of the reactor. The gaseous products leave the reactor... 

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