Aluminum molar mass

E.4 In your new nanotechnology lab you have the capability to manipulate individual atoms. The atoms on the left are aluminum atoms (molar mass 27 g-mol 1), those on the right are atoms of beryllium (molar mass 9 g-mol ). How many beryllium atoms would have to be added to the pan on the right for the masses on the two pans to be equal ... 

C03-0111. Aluminum sulfate is AI2 (804)3 (a) Compute its molar mass, (b) Compute the number of moles... 

Equation is used to calculate how much heat flows, provided we know n, C, and A T. Use the mass of the frying pan and the molar mass of aluminum to calculate n ... 

Mendeleev also predicted the existence of elements that had not yet been discovered. His arrangement of the then-known elements left some obvious holes in the periodic table. For instance, between zinc (combines with 2 Cl) and arsenic (combines with 5 Cl) were holes for one element that would combine with three chlorine atoms and another that would combine with four. Mendeleev assigned these holes to two new elements. He predicted that one element would have a molar mass of 68 g/mol and chemical properties like those of aluminum, while the other would have a molar mass of 72 g /mol and chemical properties similar to silicon. These elements, gallium (Z = 31, M M = 69.7 g/mol) and germanium (Z = 32, M M — 72.6 g/mol), were discovered within 15 years. Chemists soon verified that gallium resembles aluminum in its chemishy, while germanium resembles silicon, just as Mendeleev had predicted. 

As expected, aluminum has the greatest quantity of charge transferred per unit mass (1.00 g) of metal oxidized. This is because aluminum has the smallest molar mass and forms die most highly charged cation (3+ vs 2+ for Zn and Fe). 

Step 4 Use the molar mass of aluminum to convert the amount of aluminum to a mass. 

Nevertheless, the use of enzymes presents some drawbacks. Enzymes are expensive and large amounts are needed for polymerization. Besides, it is stiU quite challenging to synthesize high molar mass polyesters. The control of polymerization remains less efficient with enzymes than with chemical initiators such as aluminum alkoxides. 

A student performed an experiment to determine the molar mass (MM) of a volatile liquid by determining its vapor density. She placed a small amount of a volatile liquid into a flask of known volume then covered the flask with aluminum foil that had been punctured with a small pin. She then placed the apparatus into a boiling water bath and allowed the liquid to vaporize (see figure below). 

Last, multiply the number of moles of aluminum by its molar mass (which is 26.98 g) to give you grams of Al(s) ... 

CHEMICAL NAME = aluminum(lll) oxide CAS NUMBER = 1344-28-1 MOLECULAR FORMULA = Al203 MOLAR MASS = 102.0 g/mol COMPOSITION =AI(52.9%) 0(47.1%)... 

Self-Test E.2B In one day, 5.4 kg of aluminum was collected from a recycling bin. How many moles of A1 atoms did the bin contain, given that the molar mass of A1 is 26.98 g-mol 1 ... 

B,155,1 m Z. Shakhashiri, "Determination of the Molecular Mass of a Volatile Liquid," Chemical Demonstrations, A Handbook for Teachers of Chemistry, Vol. 1 (The University of Wisconsin Press, Madison, 1983) pp. 51-54. A boiling-water bath is used to heat a volatile liquid until it is vaporized, completely filling an Erlenmeyer flask covered by aluminum foil with a pinhole orifice. From atmospheric pressure, bath temperature, volume of the flask, and mass of recondensed vapor, the molar mass of the volatile liquid is determined. 

Beside the activating effect aluminum alkyl cocatalysts are also efficient molar mass control agents. Control of molar mass is achieved by the adjustment of the molar ratio of nAi/nN(j (Sects. 2.1.4, 2.2.8 and 4.5). An increase in the amount of cocatalyst results in a decrease of molar mass. A change of the nAi/ Nd-ratio also influences the rate of the polymerization reaction which is a major shortcoming in the large-scale production of Nd-BR, particularly in continuous processes. Detailed discussions of this issue are found in Sect. 2.2.8. Because of this disadvantage research on Nd-BR still strikes out to find efficient non Al-based molar mass control agents which do not influence the rate of polymerization. 

Variations of the amount of cocatalyst which are usually expressed by the molar ratio W Nd have a significant influence on polymerization rates, molar masses, MMDs and on the microstructures of the resulting polymers. These aspects are addressed in the following sections with a special emphasis on ternary catalyst systems. For ternary systems it has to be emphasized, however, that in many reports the ratio Ai/ Nd only accounts for the amount of aluminum alkyl cocatalyst and not for other Al-sources such as alkyl aluminum halides. Variations of the Ai/ Nd-ratios are also used for defined control of molar mass. This aspect is addressed in separate sections (Sects. 2.2.8 and 4.5). 

To the best of our knowledge, beside aluminum alkyls and hydridoalu-minumalkyls only vinyl chloride [206,207] and benzyl-H containing compounds such as toluene [157,384,385,409,410] are unambiguously effective in molar mass regulation. The reports on molar mass control by diethyl zinc are controversial [157,180-182,466,467]. 

In a later patent (1986) it is disclosed that phase separation of cz s-1,4-BR and BD occurs at 30 to 35 °C. Below 30 °C there is a single phase and above 35 °C there are two distinct phases of BR and BD. By the application of two polymerization steps the first of which is performed below and the second above the critical solution temperature molar mass is decreased and costs for aluminum alkyls which are used for molar mass control are reduced [511,512], Control of molar mass is further improved by the sequen-... 

In a scientific paper on the control of molar mass in gas-phase polymerization, the importance of Ai/ Nd is also emphasized, hi addition, a combination of the cocatalysts TIBA and DIBAH is recommended. By the use of two aluminum alkyl compounds the concentration ratio of two different active Nd-species is adjusted. As these two species produce different molar masses and MMDs the combination of TIBA and DIBAH allows for the control of these two parameters [229,230]. 

As discussed in Sects. 2.1 and 2.2.8 control of molar mass is an important aspect in the large-scale polymerization of dienes. In Nd-catalyzed polymerizations the control of molar mass is unique amongst Ziegler/Natta catalyst systems as standard molar mass control agents such as hydrogen, 1,2-butadiene and cyclooctadiene which are well established for Ni- and Co-systems do not work with Nd catalysts [82,206,207]. The only known additives which allow for the regulation of molar mass without catalyst deactivation are aluminum alkyls, magnesium alkyls, and dialkyl zinc. 

In contrast to these observations, no influence on molar mass was found when the amount of aluminum alkyl cocatalyst was varied for two allyl Nd-based catalyst systems (1) Nd(tj3- CsHs Cl 1.5 THF and (2) Nd( y3- C3H5)C12- 2 THF [292]. 

The addition of ZnEt2 to the catalyst system NdV/DIBAH/EASC had the same effect on the decrease of molar mass as aluminum alkyls. Therefore, a reversible exchange of polybutadienyl chains between Nd and Zn was also assumed to apply for molar mass control by ZnEt2 (Schemes 34 and 35) [180]. 

The factor A is a function of molar masses of zinc, aluminum, and oxygen atoms and additionally slightly depends on C Ai(wt). For our needs, k can be approximated by the constants A metaiiic = 2.3-2.4 and Ayompound = 1.5-1.6 for metallic and ceramic targets as well as for the compound film, respectively. Carrier concentration and mobility were determined by van der Pauw Hall effect measurements [105]. 

In the previous Sample Problem, you saw how to convert moles to mass. Often, however, chemists know the mass of a substance but are more interested in knowing the number of moles. Suppose that a reaction produces 223 g of iron and 204 g of aluminum oxide. The masses of the substances do not tell you very much about the reaction. You know, however, that 223 g of iron is 4 mol of iron. You also know that 204 g of aluminum oxide is 2 mol of aluminum oxide. You may conclude that the reaction produces twice as many moles of iron as it does moles of aluminum oxide. You can perform the reaction many times to test your conclusion. If your conclusion is correct, the mole relationship between the products will hold. To calculate the number of moles in a sample, find out how many times the molar mass goes into the mass of the sample. 

Ans. The molar mass has the same value in grams that the formula mass has in amu (Problem 7.7). Thus 1.000 mol represents 294.2 g of aluminum sulfite. 

Gleaning from Eqs. (13) to (18), a molar mass balance on the aluminum atom may be performed. Let sp i represent all the species that contain the aluminum atom standing in solution. Thus, the concentration of all the species containing the aluminum atom, is... 

What is the specific heat of aluminum chloride, which has a molar mass of 133.4 ... 

To start with, you could find the mass of your aluminum by placing it on your laboratory balance. Let s say, for the sake of argument, that the mass of your sample was 60.0 g. You could then find the molar mass of aluminum by simply looking at the periodic table. The table tells us that the atomic mass of aluminum is 27.0 u/atom. Therefore the molar mass of aluminum is 27.0 g/mole (as explained in Lesson 7-1). 

The mass of the sample of aluminum = 60.0 g The molar mass of aluminum is 27.0 g/mole... 

What is the molar mass of the elements (a) zinc and (b) aluminum ... 

What volume of hydrogen gas, measured at 22°C and 745 mmHg, is produced when 3.40 g of aluminum metal are consumed with hydrochloric acid The molar mass of aluminum is 26.98 g. The balanced equation is... 

A molecular compound of aluminum and chlorine exists in the gas phase. It is 20.24 % aluminum and 79.76 % chlorine. The molar mass of the compound is approximately 266 g. What is the molecular formula of this compound The molar masses are Al = 26.98 g,... 

A solution of 1.00 g of anhydrous aluminum chloride, AICI3, in 50.0 g of water freezes at — 1.11°C. Does the molar mass determined from this freezing... 

I lousing the molar mass of aluminum (26.98 g), we will first calculate the moles of aluminum present in 35.0 g Al ... 

Aluminum metal is produced by passing an electric current through a solution of aluminum oxide (AI2O3) dissolved in molten cryolite (NaaAIFe). Calculate the molar masses of AI2O3 and Na3AlF 5. 

---