NOTES (kap. 1,4) Flashcards
What is the definition of “The system”
is the part of the universe that we are interested in. It may be a specified
amount of a drug substance in a solution, or otherwise a mixture of substances.
What is the definition of “the surroundings?”
The part
of the universe not included in the system is termed the surroundings.
What is the definition of a substance?
a distinct, pure form of matter, i.e. a pure compound or material.
What is the definition of a Mass, m
a measure of quantity of matter in a sample (or system). The SI unit is
kg, however, in chemistry we mostly work with smaller amounts making units such as
mg or g more convenient
What is the definition of the “amount of substance, n” (stofmængde)
(“number of moles”) in a sample reported in terms of the mole.
One mole (1 mol) of substance is the amount of substance that contains as many atoms, molecules,
ions, or other entities, as the number of atoms in exactly 12 g of carbon-12
Wgat is the definition of Avogadro´s number
The number
of atoms in 1 mol of carbon-12 is equal to Avogadro´s number. The number itself is unit
less, but dividing Avogadro´s number by 1 mol gives Avogadro´s constant NA =
6.0221367 · 1023 mol-1.
What is the definition of Molar mass, M,
the mass of 1 mol of an atom or a substance, often given in units
of grams per mole (g mol-1)
What is the definition of the formula unit?
MgCl2 consists of one Mg2+ ion and two Cl- ions. That is the formula unit.
What is the defintion of Volume, V
Is a measure of the space that the sample occupies. The SI unit is m3,
however, a range of different units are widely applied, e.g., liters (1 L = 1 dm3).
What is the definition of Pressure, p?
defined as force, F, per unit area. Thus, it is a measure of the force
that a sample experiences divided by the area to which the force is applied. The SI unit is
Pa (pascal; 1 Pa = 1 N m-2).
What is the definition of the Temperature, T?
a property of a body or object determining in what direction
energy will flow when the object is brought in contact with another body. Energy will
flow from a region with higher to a region with lower temperature.
What is the definition of “termed heat”?
The transfer of energy
between objects of different temperature is termed heat.
Is our everyday assessment of
temperature as a measure of hotness or coldness of an object adequate in physical
chemistry or pharmaceutics.?
No.
The symbol T is used to represent the thermodynamic
temperature. It is an absolute temperature scale where the lowest point T = 0 is referred
to as the absolute zero. The thermodynamic temperature is expressed in kelvins (unit K)
and the scale is defined by setting the triple point of water equal to exactly 273.16 K.
The
triple point of water is the temperature where ice, liquid H2O, and H2O vapor are in
mutual equilibrium.
How can you convert Kelvin to Celcius and vise versa?
T/K = t/oC + 273.15
By the equation on top.
