01. Experimental
Chemistry
Like all
science chemistry involves measurements of various quantities. Often in
chemistry we need accurate measurements of chemicals, solids(like crystals and
powder), liquids(acid and alkali)or gases. To measure these different values we
have different quantities, for solids we have mass, for liquids and gases we
have volume.
The Mass
The
Volume
The
common laboratory instrument for measuring volume.
When we
measure the volume of a liquid, it is important to read the bottom of the curve
surface of the liquid, called the Meniscus, in the center. Syringe can also be
used to measure volumes of gases and liquids..jpg)
Time and
Temperature
Time is a very important quantity in
the laboratory. The SI unit for time is "seconds(s)". We can use a
stopwatch to measure time accurately up to 0.01s{human reaction time fyi not
important}.
Temperature
is also as important . The SI unit for temperature is "degree Celsius(oc)".
We use a thermometer to measure temperature in the lab.
What to measure
Units
Measuring device
Mass
Milligram (mg)
-Beam balance
Volume
Cubic centimeters (cm3)
-Beaker
Second (s)
-Stopwatch
Temperature
Degree Celsius (Co)
-Mercury-in-glass thermometer
01. Experimental Chemistry
Like all
science chemistry involves measurements of various quantities. Often in
chemistry we need accurate measurements of chemicals, solids(like crystals and
powder), liquids(acid and alkali)or gases. To measure these different values we
have different quantities, for solids we have mass, for liquids and gases we
have volume.
The Mass
The mass
of a substance is regarded as the amount of matter it consists of. The SI unit
for mass is "grams(g) " for small amounts and kilograms(kg) for
larger amounts.
The
apparatus used in school laboratory to measure mass is called a beam balance.
In a beam balance, a weight is moved along a horizontal scale until it balances
the mass of an object on the scale pan. Electric beam balance can measure
masses even more accurately to 0.01g or even 0.001g.
The
Volume
The
volume of a substance is the amount of space it occupies. The SI unit for
volume is "cubic centimeters(cm3)" for larger values "cubic
decimeter(dm3)" is used. Liquids are measured using graduated
beakers, for example measuring cylinder, pipette, burette. Volumetric flask is
used to, both measure fixed volume of liquid and is used for preparing solution
of known concentration.
The
common laboratory instrument for measuring volume.
When we
measure the volume of a liquid, it is important to read the bottom of the curve
surface of the liquid, called the Meniscus, in the center. Syringe can also be
used to measure volumes of gases and liquids.
Time and
Temperature
Time is a very important quantity in
the laboratory. The SI unit for time is "seconds(s)". We can use a
stopwatch to measure time accurately up to 0.01s{human reaction time fyi not
important}.
Temperature
is also as important . The SI unit for temperature is "degree Celsius(oc)".
We use a thermometer to measure temperature in the lab.
What to measure
|
Units
|
Measuring device
|
Mass
|
Milligram (mg)
Gram (g)
Kilogram (kg)
1 000 mg = 1 g
1000 g = 1 kg
1000 kg = 1 tonne
|
-Beam balance
-Electronic balance
|
Volume
|
Cubic centimeters (cm3)
1 000 cm3 = 1 dm3
1 dm3 = 1 litre
1 000 dm3 = 1 m3
|
-Beaker
-Measuring cylinder
-Pipette
-Burette
-Volumetric flask
-Syringes
|
Time
|
Second (s)
60 s = 1 min
3600 s = 1 h
|
-Stopwatch
-Stopclock
|
Temperature
|
Degree Celsius (Co)
|
-Mercury-in-glass thermometer
-Electronic thermometer
|
No comments:
Post a Comment