Mass conversions

As the name implies, mass-to-mass conversions start with a known mass of one substance and, by use of a balanced equation, seek the mass of another in the reaction. Mass-to-mass problems involve three conversion steps  

Converting the mass of the known species to moles a mass-to-mole conversion. 

Converting the moles of the sought species to mass a mole-to-mass conversion, mass (known) — mole (known) — mole (sought) — mass (sought) 

The following problem uses mass-to-mass conversions. Silver oxide, Ag20, reacts with hydrogen, H2, at high temperatures to produce silver metal, Ag, and water, HzO. The balanced equation is  

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As with all calculations of chemical amounts, we must work with moles. Because grams are asked for, we must do a mole-mass conversion this requires the molar mass of the substance, which in turn requires that we know the chemical formula. 

The question asks for mass of NO. Information about ppm tells us how many moles of NO are present in one mole of exhaust gas. We can use the ideal gas equation to determine the total number of moles of gas emitted, use the ppm information to find moles of NO, and do a mole-mass conversion to get the required mass. 

Which earlier sections must be understood before mass-to-mass conversions can be studied profitably ... 

For example, the volume of a cube is perfectly correlated to the length of each side as V = s Likewise the volume of a sphere is perfectly correlated to its radius as V = 4/377r However, the mass of such objects will be highly correlated to, v or r only when the density (d) of the materials used to form the shapes are identical, since d = mass/volume. There is no correlation of mass to s or r when vastly different densities of material are used for comparison. Thus a first-order approximation for s and r vs. mass for widely different materials would lead one to believe that there is not a relationship between volume and mass. Conversely, when working with the same material one would find that volume and mass are perfectly correlated and that there is a direct relationship between volume and mass irrespective of shape. This simple example points to the requirements for a deeper understanding of the underlying phenomena in order to draw conclusions regarding cause and effect based on correlation. 

A GW gives rise to a quadrupolar deformation normal to the direction of propagation. The deformation can be described by means of a dimensionless strain amplitude h = AL/L, where AL is the deformation of a region of space-time separated by a distance L. For example, a supernova explosion, with a mass conversion into GWs of 1% of the total mass, at a distance of 10 kpc (roughly in the centre of our galaxy), would cause a strain on earth of h 3 x 10-18 [50],... 

RMM relative molecular mass conversion factor, kg/kmol... 

We also need to perform a volume conversion. As with the mass conversion, there are many different correct volume conversions. In this case, the conversion will relate, in some way, to the length unit of feet. Thus, we might use 12 in = 1 ft. If we incorporate this, we get ... 

As in Ref. 92 for a second-order gas-phase reaction where the prevailing pressure is sufficiently low for the O/F flame (Zone II of Figure 1) to be chemical-reaction rate controlled (high diffusional mixing rate), the chemical mass conversion rate in a zone of length LIIt ck at temperature Tg may be expressed as ... 

A, mathematical model in which the pressure, temperature, mass, conversion etc. within a relieving reactor are calculated, as a variable with time. See A4.2. 

The problem gives the number of moles of NaHC03 and asks for a mole-to-mass conversion. First, calculate the formula mass and molar mass of NaHC03. Then use molar mass as a conversion factor, and set up an equation so that the unwanted unit cancels. 

According to the balanced equation, 1 mol of product is produced per mol of reactant, so we know that 0.470 mol of isobutylene can theoretically yield 0.470 mol of MTBE. To find the mass of this MTBE, we do a mole-to-mass conversion ... 

We are given V, P, and T, and we need to use the ideal gas law to calculate n, the number of moles of helium in the tire. With n known, we then do a mole-to-mass conversion. 

It is possible not only to achieve high mass conversions of polybutadiene to 1,5-hexadiene but also to create telechelic oligomers in this manner [38-40]. Catalyst selection plays an important role here ruthenium-based catalysts appeared to be best in bringing about clean conversions of high molecular weight unsaturated polymers to their telechelic oligomers [1]. 

Determine the number of moles present using the molar mass conversion. 1 mol = molar mass of substance for example 1 mol CUSO4 = 143.5 g... 

As the reaction equations show, the last propagation step supplies the initiating radical consumed in the first propagation step. From this you also see that the mass conversion of a chain reaction is described by an equation that results from the propagation steps alone they are added up, and species that occur on both sides of the reaction arrow are dropped. 

A) 1.656 g Pb(N03)2 This is a mass-to-mass conversion. You must begin by writing... 

The correct answer is (B). A mass-to-mass conversion. The solution is as follows ... 

Born in 1931 in Crete, Indiana, Jones developed an interest in the more esoteric subjects such as Voodoo, faith healing, ESP and, more importantly, techniques of mass conversion. The abilities he developed in these areas would be critical in later years in Jamestown. 

When C2D2 frequencies are used, in should be replaced by /Hq. The force constants for acetylene can be calculated from these relations using the measured vibrational frequencies, and the bond lengths can be determined from the rotational analysis described below. If one expresses the frequencies in cm units and the masses in appropriate isotopic mass units, the factors 4t7 should be replaced by 4t7 c 10 NY = 5.8918 X 10 (this includes a factor of 10 kg/g mass conversion). This substitution gives the force constants Y, kg, and Yr in N m units and the bending constants kg and kgg in units of N m. 

If the quantity of any substance is given in terms of mass instead of in moles, the mass must be changed to moles before calculating the number of moles of another substance in the reaction. If the mass of a substance is required as an answer to a problem, its number of moles must be converted to a mass. (Conversions between mass and moles are presented in Chapter 7.) (Section 10.2) If some other measure of the quantity of a substance is given or required (for example, the number of molecules of a substance), an appropriate conversion factor is needed to convert to or from moles (Section 10.3). 

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