Hydrogen molar mass

Notice that the formula of a substance must be known to find its molar mass. It would be ambiguous, to say the least, to refer to the molar mass of hydrogen. One mole of hydrogen atoms, represented by the symbol H, weighs 1.008 g the molar mass of H is 1.008 g/mol. One mole of hydrogen molecules, represented by the formula H weighs 2.016 g the molar mass of H2 is 2.016 g/mol. 

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 reactions that take place slowly under ordinary conditions occur readily in living organisms in the presence of catalysts called enzymes. Enzymes are protein molecules of high molar mass. An example of an enzyme-catalyzed reaction is the decomposition of hydrogen peroxide ... 

Denatured ethanol, 592 Density The ratio of the mass of a substance to its volume, 14-15 measuring, 14-15 electron, in hydrogen atom, 165 lipoprotein, 603-604 measuring, 14-15 molar mass and, 109-111 Dexedrine, 601 Diabetes, 593... 

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 ... 

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... 

FIGURE 5.8 The boiling points of most of the molecular hydrides of the p-block elements show a smooth increase with molar mass in each group. However, three compounds—ammonia, water, and hydrogen fluoride are strikingly out of line. 

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 ... 

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. 

Alcohols with low molar masses are liquids, and alcohols have much lower vapor pressures than do hydrocarbons with approximately the same molar mass. For example, ethanol is a liquid at room temperature, but butane, which has a higher molar mass than ethanol, is a gas. The relatively low volatility of alcohols is a sign of the strength of hydrogen bonds. The ability of alcohols to form hydrogen bonds also accounts for the solubility in water of alcohols with low molar mass. 

Ethers are more volatile than alcohols of the same molar mass because their molecules do not form hydrogen bonds to one another (Fig. 19.2). They are also less soluble in water because they have a lower ability to form hydrogen bonds to water molecules. Because ethers are not very reactive and have low molecular polarity, they are useful solvents for other organic compounds. However, ethers are flammable diethyl ether is easily ignited and must be used with great care. 

Ethers are not very reactive. They are more volatile than alcohols with similar molar masses because their molecules cannot form hydrogen bonds with one another. Crown ethers adopt shapes that can enclose ions and carry them into nonpolar solvents. 

The average molar mass of a hydrogen-bonded pair of nucleotides in a DNA molecule is 625 g-mol Each successive pair is found at a distance of 340 pm along the chain. If the total length of one strand of a DNA molecule is 0.299 m, what is the molar mass of the molecule ... 

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. 

The polymer in natural rubber consists almost entirely of ci -poly(isoprene) (1.6). The molecules are linear, with relative molar mass typically lying between 300 000 and 500 000. The macromolecular nature of rubber was established mainly by Staudinger in 1922, when he hydrogenated the material and obtained a product that retained its colloidal character, rather than yielding fragments of low relative molar mass. 

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. 

Hydrogen phthalate has one acidic hydrogen atom. As the net reaction shows, there is a 1 1 molar ratio between hydrogen phthalate and hydroxide HCg Hq O4 + OH Cg Hq O4 + H2 O The number of moles of hydrogen phthalate anions is the same as the number of moles of KHCg Hq Oq, which is calculated from its mass and molar mass ... 

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. 

Example A compound of nitrogen and hydrogen has an empirical formula NH2. The molar mass of the compound is 32 g mol-1. Calculate the molecular formula of the compound (relative atomic masses N = 14, H = 1). 

Since for every mole of hydrogen produced, one mole of zinc is consumed, the last step would be to convert these moles to grams by multiplying by the molar mass of zinc. 

Background Avogadro s law (Vin2 = V2ni), where moles, n = mw (grams/mole) exPresses the relationship between molar mass, the actual mass and the number of moles of a gas. The molar volume of a gas at STP, VSTP is equal to the volume of the gas measured at STP divided by the number of moles VSTp = pp. Dalton s Law of Partial Pressure (Ptotai = Pi + P2 + P3 +. ..) and the derivation, Pi = pp Ptotai will also be used in this experiment to predict the volume occupied by one mole of hydrogen gas at STP. 

We can use Graham s law to determine the rate of effusion of an unknown gas knowing the rate of a known one or we can use it to determine the molecular mass of an unknown gas. For example, suppose you wanted to find the molar mass of an unknown gas. You measure its rate of effusion versus a known gas, H2. The rate of hydrogen effusion was 3.728 mL/s, while the rate of the unknown gas was 1.000 mL/s. The molar mass of H2 is 2.016 g/mol. Substituting into the Graham s law equation gives ... 

Your answer must be reasonable. Hydrogen is the lightest gas (2.018 g/mol) so that any molar mass less than this value is not reasonable. 

A molar mass (molecular weight) less than 1.0 g/mol indicates an error. No molecular weight is less than the atomic weight of hydrogen. 

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