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Week 2 Chemie
Chemisch rekenen ; reactievergelijkingen en de mol
Hoofdstuk 1 Matter and Measurements
Chemistry : the study of the nature, properties and transformations of matter
Matter : the physical material that makes up the universe, everything that has mass and occupies
space
Scientific method : the systematic process of observation, hypotheses and experimentation used to
expand and refine a body of knowledge
Property : a characteristic useful for identifying a substance or object (size, color..)
Physical change : a change that does not affect the chemical makeup of a substance or object
(van ijs naar vloeistof). Chemical change : a change in the chemical makeup of a substance
(roestende ijzer van een fiets)
State of matter = physical state solid (s), liquid (l), gas (g)
Difference between a pure substance (a substance that has a uniform chemical composition
throughout) and a mixture (a blend of 2 or more substances, each of which retains its chemical
identity) : a pure substance is uniform in its chemical composition and its properties all the way down
to the microscopic level. A mixture can vary in both compositions and properties depending on how it
is made.
A homogeneous mixture is a blend of 2 or more pure substances having a uniform composition at the
microscopic level (verschil tussen puur en deze mix is met het oog niet te zien). A heterogeneous
mixture, by contrast, is a blend of 2 or more pure substances having nonuniform composition.
(verschil is tussen puur en deze mix is met het oog goed te zien)
Another difference between a pure substance and a mixture is that the components of a mixture can
be separated without changing their chemical identities. A pure substance that can not be broken
down chemically into simpler substances is called an element. Any pure substance that can be broken
down into simpler substances by a chemical change is called a chemical compound.
Chemische reactie : een proces waarbij de identiteit en de samenstelling van 1 of meerdere stoffen
veranderen. Voor de pijl is de reactant, na de pijl is het product.
Physical quantity : A physical property that can be measured (mass, volume..). A unit is a defined
quantity used as a standard of measurement.
Week 2 Chemie 1
, SI units zijn standaard afgesproken eenheden
Mass is a measure of the amount of matter in an object, weight is a measure of the gravitational pull
that the earth exerts on an object. Volume is the amount of space occupied by an object. (1L = 0,001
m^3 = 1 dm^3)
REGELS VOOR SIGNIFICANTIE : BETEKENIS VAN NULLEN
Regel 1 : Zeroes in the middle of a number are like any other digit. they are always significant
Regel 2 : Zeroes at the beginning of a number are not significant
Regel 3 : Zeroes at the end of a number and after the decimal point are significant
Regel 4 : Zeroes at the end of a number but before the decimal point may or may not be significant.
Gebruik wetenschappelijke notatie voor het vinden van het aantal significante cijfers!
REGELS VOOR SIGNIFICANTIE : AFRONDEN
!! Voor het afronden van getallen in verschillende machten is het nodig om achter de significantie te
komen om alles in dezelfde macht te schrijven.
Regel 1 : In carrying out a multiplication or division, the answer cannot have more significant figures
than either of the original numbers. Evenveel cijfers als het getal met het minste aantal significante
cijfers
Regel 2 : In carrying out an addition or subtraction, the answer cannot have more digits after the
decimal point than either of the original numbers. Het getal heeft dus evenveel cijfers achter de komma
als het getal die het minste cijfers achter de komma heeft.
All chemical reactions are accompanied by a change in energy (the capacity to do work or supply
heat). Temperature is the measure of the amount of heat energy in an object in Kelvin.
! Temperature in Kelvin = Temperature in Celsius + 273,15
! Temperature in Celsius = Temperature in Kelvin - 273,15
Not all substances have their temperatures raised to the exact same extent when equal amounts of
heat energy are added. The amount of heat needed to raise the temperature of 1 g of a substance by 1
Celsius is called the specific heat of the substance in (g x graden Celsius)
Specific heat = calories / ( grams x graden Celsius )
Heat (cal) = Mass (g) x Temperature change (delta C) x Specific Heat (cal/(gxC))
Dichtheid (density) = the physical property that relates the mass of an object to its volume
Dichtheid (g/cm^3 of g/mL) = massa (g) / volume (mL of cm^3)
The specific gravity of a substance (usually a liquid) is simply the density of a substance divided by
the density of water at the same temperature. The specific density of a liquid can be measured with a
hydrometer. which consists a weighted bulb on the end of a calibrated glass tube. The depth to which
the hydrometer sinks when placed in a fluid indicated the fluids specific gravity.
Week 2 Chemie 2
Week 2 Chemie
Chemisch rekenen ; reactievergelijkingen en de mol
Hoofdstuk 1 Matter and Measurements
Chemistry : the study of the nature, properties and transformations of matter
Matter : the physical material that makes up the universe, everything that has mass and occupies
space
Scientific method : the systematic process of observation, hypotheses and experimentation used to
expand and refine a body of knowledge
Property : a characteristic useful for identifying a substance or object (size, color..)
Physical change : a change that does not affect the chemical makeup of a substance or object
(van ijs naar vloeistof). Chemical change : a change in the chemical makeup of a substance
(roestende ijzer van een fiets)
State of matter = physical state solid (s), liquid (l), gas (g)
Difference between a pure substance (a substance that has a uniform chemical composition
throughout) and a mixture (a blend of 2 or more substances, each of which retains its chemical
identity) : a pure substance is uniform in its chemical composition and its properties all the way down
to the microscopic level. A mixture can vary in both compositions and properties depending on how it
is made.
A homogeneous mixture is a blend of 2 or more pure substances having a uniform composition at the
microscopic level (verschil tussen puur en deze mix is met het oog niet te zien). A heterogeneous
mixture, by contrast, is a blend of 2 or more pure substances having nonuniform composition.
(verschil is tussen puur en deze mix is met het oog goed te zien)
Another difference between a pure substance and a mixture is that the components of a mixture can
be separated without changing their chemical identities. A pure substance that can not be broken
down chemically into simpler substances is called an element. Any pure substance that can be broken
down into simpler substances by a chemical change is called a chemical compound.
Chemische reactie : een proces waarbij de identiteit en de samenstelling van 1 of meerdere stoffen
veranderen. Voor de pijl is de reactant, na de pijl is het product.
Physical quantity : A physical property that can be measured (mass, volume..). A unit is a defined
quantity used as a standard of measurement.
Week 2 Chemie 1
, SI units zijn standaard afgesproken eenheden
Mass is a measure of the amount of matter in an object, weight is a measure of the gravitational pull
that the earth exerts on an object. Volume is the amount of space occupied by an object. (1L = 0,001
m^3 = 1 dm^3)
REGELS VOOR SIGNIFICANTIE : BETEKENIS VAN NULLEN
Regel 1 : Zeroes in the middle of a number are like any other digit. they are always significant
Regel 2 : Zeroes at the beginning of a number are not significant
Regel 3 : Zeroes at the end of a number and after the decimal point are significant
Regel 4 : Zeroes at the end of a number but before the decimal point may or may not be significant.
Gebruik wetenschappelijke notatie voor het vinden van het aantal significante cijfers!
REGELS VOOR SIGNIFICANTIE : AFRONDEN
!! Voor het afronden van getallen in verschillende machten is het nodig om achter de significantie te
komen om alles in dezelfde macht te schrijven.
Regel 1 : In carrying out a multiplication or division, the answer cannot have more significant figures
than either of the original numbers. Evenveel cijfers als het getal met het minste aantal significante
cijfers
Regel 2 : In carrying out an addition or subtraction, the answer cannot have more digits after the
decimal point than either of the original numbers. Het getal heeft dus evenveel cijfers achter de komma
als het getal die het minste cijfers achter de komma heeft.
All chemical reactions are accompanied by a change in energy (the capacity to do work or supply
heat). Temperature is the measure of the amount of heat energy in an object in Kelvin.
! Temperature in Kelvin = Temperature in Celsius + 273,15
! Temperature in Celsius = Temperature in Kelvin - 273,15
Not all substances have their temperatures raised to the exact same extent when equal amounts of
heat energy are added. The amount of heat needed to raise the temperature of 1 g of a substance by 1
Celsius is called the specific heat of the substance in (g x graden Celsius)
Specific heat = calories / ( grams x graden Celsius )
Heat (cal) = Mass (g) x Temperature change (delta C) x Specific Heat (cal/(gxC))
Dichtheid (density) = the physical property that relates the mass of an object to its volume
Dichtheid (g/cm^3 of g/mL) = massa (g) / volume (mL of cm^3)
The specific gravity of a substance (usually a liquid) is simply the density of a substance divided by
the density of water at the same temperature. The specific density of a liquid can be measured with a
hydrometer. which consists a weighted bulb on the end of a calibrated glass tube. The depth to which
the hydrometer sinks when placed in a fluid indicated the fluids specific gravity.
Week 2 Chemie 2
