Chapter 2: Measurement, Problem Solving, and the Mole Concept Flashcards
accuracy
A term that refers to how close a measured value is to the actual value.
Avogrado’s number
The number of 12C atoms in exactly 12 g of 12C; equal to 6.0221421 x 1023.
calorie (cal)
A unit of energy defined as the amount of energy required to raise one gram of water by 1 °C; equal to 4.184 J.
Calorie (Cal)
Equivalent to 1000 lowercase “c” calories. Same as kilocalorie (kcal); 1 Cal = 1 kcal = 1000 cal
conversion factor
A factor used to convert between two different units; a conversion factor can be constructed from any two quantities known to be equivalent.
density
The ratio of an object’s mass to its volume. It is a characteristic physical property of a substance and its substance also depends on its temperature.
endothermic
Describes a process that absorbs heat from its surroundings.
dimensional analysis
The use of units as a guide to solving problems.
energy
The capacity to do work.
The total energy of an object is a sum of its kinetic energy and its potential energy.
exothermic
Describes a process that releases heat to its surroundings.
intensive property
A property such as density that is independent of the amount of a given substance.
extensive property
A property that depends on the amount of a given substance, such as mass.
joule (J)
The SI unit for energy: equal to 1 kg • m2/s2.
kilowatt-hour (kWh)
An energy unit used primarily to express large amounts of energy produces by the flow of electricity; equal to 3.60 x 106 J.
kinetic energy
The energy associated with motion of an object.
KE = (1/2)mv2
m = kg; v = m/s
law of conservation of energy
The law stating that energy can neither be created nor destroyed, only converted from one form to another.
molar mass
The mass in grams of one mole of atoms of an element; numerically equivalent to the atomic mass of the element in amu.
mole (mol)
A unit defined as the amount of material containing 6.0221421 x 1023 (Avogadro’s number) particles.
potential energy
The energy associated with the position or composition of an object.
precision
A term that refers to how close a series of measurements are to one another or how reproducible they are.
random error
Error that has equal probability of being too high or too low. Almost all measurements have some degree of random error. Random error can, with enough trials, average itself out.
systematic error
Error that tends toward being consistently either too high or too low. Does not average out with repeated trials.
thermal energy
A type of kinetic energy associated with the temperature of an object, arising from the motion of individual atoms or molecules in the object; see also heat.
work
The result of a force acting through a distance.
