MEASUREMENTS Flashcards
The “Absolute temperature scale” begins at absolute zero and only has positive values
Kelvin ( K )
The temperature scale used by science, formally called centigrade, most commonly used scale around the world
Celsius ( oC )
Commonly used scale in the U.S. for our weather reports
Fahrenheit ( oF )
Refers to reproducibility or how close the measurements are to each other
Precision
Refers to how close a measurement is to the real value
Accuracy
Values that are either all higher or all lower than the actual value
Systematic Error
In the absence of systematic error, some values that are higher and some that are lower than the actual value
Random Error
Operation that, under specified conditions, in a first step, establishes a relation between the quantity values with measurement uncertainties provided by measurement standards and corresponding indications with associated measurement uncertainties (of the calibrated instrument or secondary standard) and, in a second step, uses this information to establish a relation for obtaining a measurement result from
Calibration
ratio of mass over volume
Density
Any characteristic of matter that does not depend on the amount of the substance present
Intensive Property
Any characteristic of matter that depends on the amount of matter being measured
Extensive Property
The Density of Water is
1 g/mL
defined as the mass per unit volume of a substance, and it is a physical property of matter
Density
The units of density are commonly expressed as
g/cm for solids, g/mL for liquids, and g/L for gases
Your eye must be level with the volume mark and the pipet vertical. If you are looking up at the pipet, the meniscus will be too high when it appears to align with the mark. It you are looking down at the pipet, the meniscus will be too low when it appears to align with the mark
Parallax error
the simple average of your replicas
The mean
related to the spread in values of replicas of your experiment
The standard deviation
The standard deviation of the mean, σ𝑥̅, is also called the
estimated standard error
measure of the average kinetic energy of molecules in a substance
Temperature
5 types of glasses
- Soda lime glass
- Lead glass
- Borosilicate glass
- Fused silicate glass (Quartz glass)
- Ceramics
A substance that is made from clay and hardened by heat in a furnace maintained at a high temperature
Ceramics
Sand is heated until it melts at 1700°C, and the viscous liquid is cooled immediately which produces a transparent solid with an uneven arrangement of atoms. Properties: Cannot expand or contract easily when there are temperature changes. Difficult to be made into different shapes. High melting point.
Fused silicate glass (Quartz glass)
Boron oxide (B2O3) and sodium carbonate is added to molten silica. Properties: Able to withstand high temperature and chemical reaction. It does not break easily. High melting point. Transparent to light and infrared ray but no to ultraviolet ray.
Borosilicate glass
A mixture of lead(II) oxide, sodium oxide and silica, Lead glass of better quality contains a higher percentage of PbO. Properties: High refractive index and density, Glittering and attractive surface, Very transparent.
Lead glass
Limestone (CaCO3) and sodium carbonate(Na2CO3) are mixed with molten silica and cooled down. Properties: Low melting point, Easily to be shaped(soft glass), Easily broken, Transparent.
Soda lime glass
If a piece of glassware is manufactured to contain liquids, the volume of the liquid inside will be the amount indicated by the markings on the outside of the glassware
TC – To contain
If a piece of glassware is manufactured to deliver a specific volume of liquid, the amount indicated on the glassware is correct only once the liquid is dispensed into another container.
TD – To deliver
used to rinse pieces of glassware and to add small quantities of water
Wash Bottle
used to measure small amounts of liquid very accurately. Never pipet by mouth use pipetting aids
Volumetric Pipet
used to secure glassware to a ring standard
Utility Clamp
used to prepare solutions to an accurate volume
Volumetric Flask
used to measure temperature in celsius
Thermometer
used to light a bunsen burner
Striker
used to hold and mix liquids
Test Tube
used to hold a test tube, particularly when hot
Test Tube Clamp
used to hold several test tubes at one time
Test tube rack
used to transfer solids
Scoopula
used for stirring and mixing
Stirring Rod
used to draw liquids into a pipet
Pipet Bulb
used with a ring stand to hold glassware, such as a beaker or a funnel
Ring Clamp
used to hold or clamp laboratory glassware and other equipment in place, so it does not fall down or come apart
Ring Stand
used to heat liquids for evaporation
Evaporating Dish
used to pick up or hold small objects
Forceps
used to transfer liquids or fine-grained materials into containers with small openings. Also used for filtration
Funnel
used to measure a precise volume of a liquid
Graduated Cylinder
used to crush and grind materials
Mortar and pestle
used to hold crucibles
Crucible tongs
used to hold and mix chemicals. The small neck is to facilitate mixing without spilling
Erlenmeyer Flask
used for dispensing an accurate volume of a liquid
buret
used to support a crucible during heating
Clay Triangle
used for holding chemicals during heating to very high temperature
Crucible
used to hold crucibles
Crucible Tongs
used for measuring mass
balance
used to hold, mix, and heat liquids
Beaker
used to pick up beakers
Beaker Tong
frequently used as a heat source in the absence of flammable materials
Bunsen Burner
