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Small amounts of hydrogen chloride for laboratory use can be generated in an HCl generator by dehydrating hydrochloric acid with either sulfuric acid or anhydrous calcium chloride. Alternatively, HCl can be generated by the reaction of sulfuric acid with sodium chloride: [17] NaCl + H 2 SO 4 → NaHSO 4 + HCl↑. This reaction occurs at room ...
There is a 1:1 molar ratio of NH 3 to NO 2 in the above balanced combustion reaction, so 5.871 mol of NO 2 will be formed. We will employ the ideal gas law to solve for the volume at 0 °C (273.15 K) and 1 atmosphere using the gas law constant of R = 0.08206 L·atm·K −1 ·mol −1 :
There are other definitions of standard gas conditions used in the USA besides 60 °F and 1 atmosphere. That being understood: 1 Nm 3 of any gas (measured at 0 °C and 1 atmosphere of absolute pressure) equals 37.326 scf of that gas (measured at 60 °F and 1 atmosphere of absolute pressure).
Another scale is mass fraction or, equivalently, percent by mass. [2] For example, the abundance of oxygen in pure water can be measured in two ways: the mass fraction is about 89%, because that is the fraction of water's mass which is oxygen. However, the mole fraction is about 33% because only 1 atom of 3 in water, H 2 O, is oxygen.
It is a dimensionless quantity with dimension of / and dimensionless unit of moles per mole (mol/mol or mol ⋅ mol-1) or simply 1; metric prefixes may also be used (e.g., nmol/mol for 10-9). [5] When expressed in percent , it is known as the mole percent or molar percentage (unit symbol %, sometimes "mol%", equivalent to cmol/mol for 10 -2 ).
The number density (symbol: n or ρ N) is an intensive quantity used to describe the degree of concentration of countable objects (particles, molecules, phonons, cells, galaxies, etc.) in physical space: three-dimensional volumetric number density, two-dimensional areal number density, or one-dimensional linear number density.
Therefore, an alternative form of the ideal gas law may be useful. The chemical amount, n (in moles), is equal to total mass of the gas (m) (in kilograms) divided by the molar mass, M (in kilograms per mole): =. By replacing n with m/M and subsequently introducing density ρ = m/V, we get:
A closely related concept is the atomic percent (or at.%), which gives the percentage of one kind of atom relative to the total number of atoms. [1] The molecular equivalents of these concepts are the molar fraction , or molar percent .