The Core of Chemistry 80 pg Flashcards
Who invinted the water thermometer?When?
Galileo Galilei in 1593
How do digital thermistor work?
Thermistors contain a semiconductor substance. A semiconductor is a substance that conducts an electric current well at high temperatures but not at low temperatures. Therefore, at high temperatures, their resistance is low. At low temperatures, their resistance is high. A microchip inside measures this resistance. Then, the microchip coverts that measurement into a temperature measurement. It then appears on a digital display.
How do bimetallic strips work?
These thermometers measure temperature based on the expansion of metals. Inside these thermometers, two different metals are bonded together. Those metals will expand at different rates when heated. As a result, the strip will bend. Most of the time these two metals are copper and steel.
Who invented the first mercury thermometer? When? This person also invented a scale, what was it called?
In 1714, Daniel Gabriel Fahrenheit invented the first mercury thermometer. Ten years later, he developed a temperature scale—the Fahrenheit scale
What replaces mercury in thermometers, why?
Mercury is dangerous to humans. If a mercury thermometer breaks, it can be a hazard. Alcohol is considered to be a safer alternative.
What is a manometer? How does it work?
A manometer is a device used to measure the pressure of a fluid. They often measure pressure based on differences in the height and position of a column of liquid in a “U” tube. The legs of the manometer are connected to separate sources of pressure. The liquid will rise in the leg with the lower pressure and drop in the other leg. One leg of the tube is a reference leg, often left open to the atmosphere. The other leg of the tube is the measuring leg. They are usually used to measure pressures close to atmospheric pressure.
What is a barometer? What are they generally used for? How does it work?
A barometer is a device (a type of manometer) used to measure atmospheric pressure. When the water or mercury level rises in a barometer, the air pressure is increasing. When the water or mercury level falls, the air pressure is decreasing. Mercury barometers are commonly used in weather reporting.
How do aneroid pressure gauges work?
They contain a coiled tube called a Bourdon Tube A Bourdon tube contracts like a spring when pressure increases. As the tube coils (or uncoils), it turns a pointer. The pointer is on the face of the gauge and marks the pressure. Tip: aneroid= without fluid.
Who invented the mercury barometer. How did this person make their discovery?
Evangelista Torricelli,an Italian physicist and mathematician, developed the first mercury barometer in the early 1640s while he investigating vacuums. He determined that the height of mercury was only 1/14 the height of water. This is because mercury is fourteen times as dense as water. The level of mercury varied from day to day. He concluded that the difference was caused by changes in atmospheric pressure. He also determined that the space above the mercury in the barometer must contain a vacuum. The “torr,” a unit of pressure, is named after him.
What is a pipette? How does it work?
A pipette is a device used to measure and move a small amount of liquid from one container to another. Liquid is drawn up into a pipette by suction. A vacuum is created in the pipette. When the pipette is placed into a liquid, the vacuum creates a suction. The suction causes the liquid to move up into the pipette.
What is a Pasteur pipette? How does it work?
A Pasteur pipette is a long, skinny tube with a bulb at one end. These pipettes are like eye droppers. When you squeeze the bulb, a vacuum is created in the pipette. When you release the bulb, the liquid moves up into the pipette. These pipettes are used to move a liquid from one container to another but, they do not provide accurate measurements
What is a Volumetric pipette. How does it work?
Volumetric pipette: a long, skinny tube with an enlargement in the middle and a suction device at one end. These pipettes are used to accurately measure a specific volume of liquid. The size of the enlarged middle section determines the volume for that pipette. Therefore, these pipettes come in different sizes, usually ranging from 5 mL to 50 mL.
What is a Bunsen Burner? How does it work?
A Bunsen burner is a gas burner that produces a single, steady flame for laboratory experiments. The flame burns at the top of a vertical metal tube connected to a natural gas source. A valve on the Bunsen burner controls the amount of gas that flows into it. As more gas flows into the burner, the flame gets bigger. A “collar” controls the amount of air that mixes with the fuel. It can be rotated to control the amount of air flowing into the burner. The amount of air affects the quality of the flame. The ideal flame is bluish in color, not yellow or smoky
Who improved the spectroscope (now called the Bunsen Burner). When? Why?
In 1855, Robert Bunsen improved the heating burner that is named after him. (He did not invent it.) Up until Bunsen’s improvements, the burner’s flames were smoky, flickered too much, and did not produce much heat. Tip: Bunsen and his colleague Gustav Kirchhoff developed a spectroscope in 1859 that allowed them to discover the elements cesium and rubidium.
Who invented the spectroscope?
The spectroscope was initially invented in 1819 by Joseph Von Fraunhofer
Where can you find chemical safety information? What kind of information might you find there?
A good place to find chemical safety information is on the label of the chemical’s container. Product container labels include important information about storage and handling. They may also include warnings, first aid information, and other emergency details. Labels should also contain more information about the chemical, such as the name, where it was manufactured, precautionary statements, and other information that will help you safely handle that chemical.
What are the four chemical safety ratings ?
Health rating, flammability rating, reactivity rating,and Special warning Here is what the symbol looks like:
What is the health rating? How does its rating system work?
The health rating indicates the degree of harm that exposure to the substance would cause a person. It indicates the amount of protective equipment a person needs in order to safely work with this substance. A rating of 4 would most likely mean that specialized equipment is needed to work safely, while a rating of 1 may mean that only basic protection, such as goggles and gloves, is needed.
What is the flammability rating?
It indicates the likelihood of the substance to vaporize, ignite, and burn.
What is the reactivity rating
It indicates the likelihood of the substance to release energy by chemical reaction or explosion.
What is the special warning section? What kind of symbols might show up there?
A “W” with a line through(chemical reacts with water) OXY (oxidizer) ACID (acid) ALK (alkali) COR (corrosive) RAD (radiation hazard).
What is a safety data sheet (SDS)? What kind of information can you find on it?
An SDS gives workers, emergency personnel, and all of us information about theproper way to handle or work with a certain substance. An SDS includes: • Detailed information about the chemical identity and all ingredients of the product. • Physical and chemical properties of the product (melting point, boiling point, etc.). • Potential hazards associated with the substance (health, storage cautions, flammability, radioactivity, reactivity, etc.). • Emergency actions and first aid procedures if an accident happens. • Storage and handling precautions. • Safe disposal information. In addition, an SDS includes information to identify the manufacturer. This includes the manufacturer’s address, as well as emergency phone numbers. Tip:The Occupational Safety and Health Administration (OSHA) recently made changes to the way that chemical safety information is communicated. These changes are meant to allow people to better understand how to safely handle chemicals. Beginning in June 1, 2015, all chemical labels should have basic information about how to safely handle and work with those chemicals.
What do warning symbols tell you?
They help make sure that people use chemicals responsibly to keep us safe.
What is this symbol:
What does it indicate?
The gas symbol indicates that there are gases that may be compressed, under pressure, or in other forms that may require special care when handling. The environmental hazard symbol indicates th
What is this symbol:
What does it indicate?
The environmental hazard symbol indicates that the chemicals contained are hazardous to the environment and to aquatic life. This symbol is especially important during disposal. You will want to be careful about how to dispose these chemicals to avoid causing any harm.
What is this symbol:
What does it indicate?
The explosive symbol indicates the potential for an explosive situation. The substance may explode if it comes into with fire or if it experiences shocks or friction. Read and follow instructions to handle these chemicals safely.
What is this symbol:
What does it indicate?
The flame symbol indicates the presence of a flammable substance. • A flammable substance is one that easily ignites. • Flammable substances include gasoline, propane, and ethanol. When working near an open flame, tie back or cover loose hair and avoid loose or bulky clothing. When working with a flammable substance, be sure to avoid anything that could start a fire, such as electrical sparks or a hot surface.
What is this symbol:
What does it indicate?
The oxidizer symbol warns you to keep the substance away from flammable and combustible materials. An oxidizing substance easily gives off oxygen, transfers oxygen atoms, or behaves like oxygen in a chemical reaction. Just because a substance is an oxidizer does not mean it is combustible. However, oxidizers can fuel a fire and make it more difficult to put a fire out.
What is this symbol:
What does it indicate?
The corrosive symbol indicates the presence of a substance that can cause damage to skin, eyes, and can potentially destroy metals. These substances can destroy or cause major damage to other substances. Often times these corrosives are strong acids or bases. As with other chemicals, remember to avoid contact with skin, eyes, and clothing and do not inhale the vapors.
What is this symbol:
What does it indicate?
This warning, or irritant and sensitizer, symbol is used to indicate those toxic chemicals. Although these chemicals are still hazardous, they indicate a less severe toxicity than those labeled with the skull and cross-bones or the chronic health hazard symbols. These chemicals can cause irritation and be harmful if you come in contact with them, so you should always work safely and pay attention to other hazard information about them.
What is this symbol:
What does it indicate?
The skull and cross-bones, or acute toxicity, symbol is used to indicate a health hazard. It often means that there is a toxic or poisonous substance inside the container with the symbol or in close proximity to that location.
What is this symbol:
What does it indicate?
The chronic health hazard symbol is used to indicate chemicals that are very harmful to the human body. Chemicals with this symbol can be toxic or somehow detrimental to your health. You should always look for other instructions to safely handle these substances. As with the other health symbols mentioned above, do not let such a substance come in contact with your skin. Do not eat or drink the substance, and do not inhale its vapors. If you do come into contact with a substance labelled with this symbol, you should seek medical attention or call a poison control hotline.
