Mass conversion factors

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

Now, use a molar-mass conversion factor to find < reaction> or AH, for 1 mol of methane. 

How can we get out of this difficulty One way is to always work exclusively in SI. In that case kg will always mean kgm, and kgf will never appear. Instead the unit of force will always be the N = (1/9.8) kgf. However, then we will be unable to deal with the public, who speak (unintentionally) in kgf and Ibf, or to understand those parts of the enginepring literature that use kgf and Ibf. The other way is to decide we must live w ith the kgf and Ibf, and so we will have to regularly use the force-mass conversion factor whenever units of force and of mass occur in the same equation This conversion factor has the values shown i... 

Furthermore, we must know some history toj understand the older literature. First, we must know that many older textbooks and articles used the symbol to stand for this force-mass conversion factor. So whenever we see a in an equation, we must recognize it as a reminder that we must use the force-mass conversion factor. We must not confuse the force-mass conversion factor, with the acceleration of gravity g. 

Second, we should recognize that engineers using to evade this difficulty by inventing two new units the and the poundal (pdl) [1 pdl = (1/32.2) Ibf]. Using these, we have the following force-mass conversion factors ... 

In summary, if you can do all your work in SI, you need never be concerned about force-mass conversions (N = kg m/s ) or energy conversions (J = N-m=W s). If you are confronted with problems (or literature, or current U.S. legal definitions) involving the kgf, Ibf, cal, kcal, or Btu, you must follow the rules outlined above Always write down the dimensions, treat the dimensions as algebraic quantities, and multiply by 1 as often as needed to get the quantities into the desired set of units, using the appropriate values of the force-mass conversion factor and the thermal-mechanical energy conversion factor. Even in SI, if you stray from the basic units (m, kg, s, A, K, mol, and cd), you will need conversion factors such as... 

In the third part of Ex. 1.3, what would have happened if we had taken the force-mass conversion factor as 32.21bm ft/lbf-sec instead of 9.8 kgm-m/ kgf sec ... 

To find the answer in joules or. foot-pounds-force, we use the force-mass conversion factor ... 

Table 439. Key mass conversion factors between various titanium compoimds...

This route requires two additional pieces of data the molar mass of the given substance and the mole ratio. The molar mass is determined by using masses from the periodic table. We will follow a procedure much like the one used previously by using the units of the molar mass conversion factor to guide our mathematical operations. Because the known quantity is a mass, the conversion factor will need to be 1 mol divided by molar mass. This conversion factor cancels units of grams and leaves units of moles (see Figure 2.3 below). 

Equation 3.23 represents the balance required between flows, in and out, given the production volumes at a manufacturing facility ft, corresponding shipments to converting facilities i, and sales of semi-finished products to customer zones k, considering mass conversion factors. These balance constraints are enforced only for the products p defined as part of the set PRSS. 

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