Conversion factor molarity

Caicuiate the mass of each reactant and product by multiplying the number of moles by the conversion factor molar mass. 

Biological Sample Mass Units Conversion Factor Molar Units Reft... 

USP conversion factors Molar conversion factors (g,mol/IU) a-Tocopherol conversion factors (mg/IU)... 

Solution To calculate the number of H atoms, we first must convert grams of urea to moles of urea using the molar mass of urea. This part is similar to Example 3.2. The molecular formula of urea shows there are four moles of H atoms in one mole of urea molecule, so the mole ratio is 4 1. Finally, knowing the number of moles of H atoms, we can calculate the number of H atoms using Avogadro s number. We need two conversion factors molar mass and Avogadro s number. We can combine these conversions... 

Before you can solve any stoichiometry problem, you must have the reaction equation and the conversion factors between moles and quantities of Given and Wanted substances. For convenience, we will use the expression starting steps to describe these items. Thus, complete the starting steps means to write and balance the equation, if it is not given, and determine the conversion factors. Molar mass is the conversion factor in this section others will appear later. 

The dimensions of permeabiUty become clear after rearranging equation 1 to solve for P. The permeabiUty must have dimensions of quantity of permeant (either mass or molar) times thickness ia the numerator with area times a time iaterval times pressure ia the denomiaator. Table 1 contains conversion factors for several common unit sets with the permeant quantity ia molar units. The unit nmol/(m-s-GPa) is used hereia for the permeabiUty of small molecules because this unit is SI, which is preferred ia current technical encyclopedias, and it is only a factor of 2, different from the commercial permeabihty unit, (cc(STP)-mil)/(100 in. datm). The molar character is useful for oxygen permeation, which could ultimately involve a chemical reaction, or carbon dioxide permeation, which is often related to the pressure in a beverage botde. 

Strategy (1) Start by calculating the number of moles of Fe2+. Then (2) use the coefficients of the balanced equation to find the number of moles of Mn04. Finally, (3), use molarity as a conversion factor to find the volume of KMn04 solution. 

A chemical equation tells us the relations between the amounts (in moles) of each reactant and product. By using the molar masses as conversion factors, we can express these relations in terms of masses. 

Molar mass can be thought of as a conversion factor between mass in grams and number of moles. These conversions are essential in chemistry, because chemists count amounts of substances in moles but routinely... 

A Both the density and the molar mass of Pb serve as conversion factors. 

IB For one conversion factor we need the molar mass ofMgCl2. 

B We need the molar mass of ethyl mercaptan for one conversion factor. 

A The molar mass of halothane is given in Example 3-3 in the text as 197.4 g/mol. The rest of the solution uses conversion factors to change units. 

B Care must be taken to use the proper units/label in each conversion factor. Note, you cannot calculate the molar mass of an impure material or mixture. 

Solve these kinds of problems by using the definition of molarity and conversion factors. In parts (b) and (c), you must first convert your mass in grams to moles. To do so, you divide by the molar mass from the periodic table (flip to Chapter 7 for details). In addition, be sure you convert milliliters to liters. 

Again, conversion factors are the way to approach these kinds of problems. Each problem features a certain volume of solution that contains a certain solute at a certain concentration. To begin each problem, convert your volume into liters — part (c) has already done this for you. Then rearrange the molarity formula to solve for moles ... 

If we want an amount other than 1 mol, we use the molar mass as a conversion factor from the stated number of moles to the mass required ... 

Then use this molarity as a conversion factor to calculate the number of moles of solute in the stated volume of solution. The mass of solute is given and the number of moles of solute present is now known therefore, to find the molar mass of the solute, divide the mass by the amount. To avoid rounding errors, do the numerical calculation at the end. 

In effect, molar mass acts as a conversion factor between numbers of molecules and mass. If you know the mass of a sample, you can calculate how many molecules you have if you know how many molecules you have, you can calculate their total mass. Note, though, that it s always necessary when using a molar mass to specify the formula of the substance you re talking about. For example, 1 mol of hydrogen atoms, H, has a molar mass of 1.0 g/mol, but 1 mol of hydrogen molecules, H2, has a molar mass of 2.0 g/mol. 

Now that we know how many moles of ethylene we have (0.536 mol), we also know from the balanced equation how many moles of HC1 we need (0.536 mol), and we have to do a mole-to-gram conversion to find the mass of HC1 required. Once again, the conversion is done by calculating the molecular mass of HC1 and using molar mass as a conversion factor ... 

The problem gives the mass of sucrose and asks for a mass-to-mole conversion. Use the molar mass of sucrose as a conversion factor, and set up an equation so that the unwanted unit cancels. 

Use molar mass of Cl2 Use coefficients in as a conversion factor the balanced equation to find mole ratios... 

First, find out how many moles of Cl2 are in 25.0 g of Cl2. This gram-to-mole conversion is done in the usual way, using the molar mass of Cl2 (70.9 g/mol) as the conversion factor ... 

We need to calculate the amount of methyl tert-bu tyl ether that could theoretically be produced from 26.3 g of isobutylene and compare that theoretical amount to the actual amount (32.8 g). As always, stoichiometry problems begin by calculating the molar masses of reactants and products. Coefficients of the balanced equation then tell mole ratios, and molar masses act as conversion factors between moles and masses. 

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