There is a small bend in the mercury channel of a clinical thermometer that uses mercury. You must shake the thermometer to get the mercury from a previous reading from the thermometer back into the bulb (or at least to a low temperature number) so that a new reading can be taken.
Shaking the thermometer hard is what gets the mercury down and ultimately drives it through the constriction so that it rejoins into a single column. In effect, you are making the glass accelerate so fast that it leaves the mercury behind.
No. But glassware is not a crystalline rigid material, and has some memory of recent thermal movement. Thermometers that have been calibrated at manufacture, will have a couple of tiny scratch marks along the scale, and the graduations in between are interpolated.
You must shake the thermometer to get the mercury from a previous reading from the thermometer back into the bulb (or at least to a low temperature number) so that a new reading can be taken.
The average normal body temperature is generally accepted as 98.6°F (37°C). Some studies have shown that the "normal" body temperature can have a wide range, from 97°F (36.1°C) to 99°F (37.2°C). A temperature over 100.4°F (38°C) most often means you have a fever caused by an infection or illness.
The simple clinical thermometer is essentially just a capillary tube with mercury inside it. Mercury will never lose its property of expansion with heat. Your thermometer is thus forever.
If the liquid in the thermometer bulb is any color other than silver, it is not a mercury thermometer. If the liquid in your thermometer bulb is silver, then the liquid might be: mercury, or. a non-toxic compound that looks similar to mercury.
Diluting acids and bases
Adding water to an acid or base will change its pH. Water is mostly water molecules so adding water to an acid or base reduces the concentration of ions in the solution. Similarly, when an alkali is diluted with water the concentration of OH - ions decreases.Stir the solution.
- Always add acid to the water, not the other way around.
- When mixing two acids, always add the stronger acid to the weaker.
- It is possible to add half the required amount of water, diluting it fully, then slowly mixing in the remaining water.
A large amount of heat is released when strong acids are mixed with water. Adding more acid releases more heat. If you add water to acid, you form an extremely concentrated solution of acid initially. So much heat is released that the solution may boil very violently, splashing concentrated acid out of the container!
Stir the solution.
- Always add acid to the water, not the other way around.
- When mixing two acids, always add the stronger acid to the weaker.
- It is possible to add half the required amount of water, diluting it fully, then slowly mixing in the remaining water.
If you add water to acid it forms an extremely concentrated solution of acid initially. So much heat is released that the solution may boil very violently, splashing concentrated acid out of the container and all this because the reaction is exothermic. So it is always safer to add acid to water, and not water to acid.
After measuring out your concentrated acid and water, the acid must always be added to the water. This is because when the two mix, heat is generated – this is called the “Enthalpy of solution” or “enthalpy of dissolution”.
When you mix acid with water, it's extremely important to add the acid to the water rather than the other way around. This is because acid and water react in a vigorous exothermic reaction, releasing heat, sometimes boiling the liquid. When you add water to acid, the water boils and the acid may splatter and splash!
Adding a base decreases the concentration of H3O+ ions in the solution. An acid and a base are like chemical opposites. If a base is added to an acidic solution, the solution becomes less acidic and moves toward the middle of the pH scale. This is called neutralizing the acid.
acid is added to water, it won't spit; the solution will still heat up, but it will do so gradually. When you work with acids, you MUST ALWAYS wear safety spectacles; or glasses if you are a speccy.
However, don't get too comfortable: avoid wearing things like leggings, tights, pajama pants, and yoga pants. While they do, technically, cover your legs, the materials used to make these garments is too thin to adequately protect you from chemical spills or broken glass.
Top 10 Lab Safety Rules
- Rule #1 - WALK.
- Rule #2 - PROPER LAB ATTIRE.
- Rule #3 - HANDLING CHEMICALS.
- Rule #4 - HANDLING EQUIPMENT.
- Rule #5 - BROKEN GLASS.
- Rule #6 - EYE WASH/SHOWER.
- Rule #7 - FIRE SAFETY.
- Rule #8 - EATING/DRINKING IN LAB.
Food ingestion and chemically contaminated drinks are sources of chemical exposure. Thus, chemical exposure takes place upon consuming food or beverages stored with chemicals. Therefore, eating or drinking in the lab is strictly forbidden.
Proper Laboratory Clothing
Approved safety goggles. Long pants (An acceptable, but not reccommended, alternative is to wear shorts, a skirt, or a lab coat such that your knees are covered when you are sitting down.) Shoes that completely cover the foot.List four things students should be before beginning any lab. Read instructions, Tie back long hair, Roll back loose sleeves, Put on safety goggles. List two things students should do after a lab. Wash hands with soap and water, Clean up your work area.
The last thing you should do before leaving the lab, after an experiment, is to wash your hands. Most chemicals are toxic to some extent, so clean your hands before leaving. Take appropriate action, then notify the instructor. You do not need permission to use safety equipment.
While in the laboratory you should have the following:
Approved safety goggles. A shirt that covers the stomach and lower back as well as the upper arms. Long pants (An acceptable, but not reccommended, alternative is to wear shorts, a skirt, or a lab coat such that your knees are covered when you are sitting down.)Answer and Explanation: The most important lab safety rule is to know the location of and how to use safety equipment, such as a fire extinguisher.
The 10 Most Important Lab Safety Rules
- The Most Important Lab Safety Rule.
- Know the Location of Safety Equipment.
- Dress for the Lab.
- Don't Eat or Drink in the Laboratory.
- Don't Taste or Sniff Chemicals.
- Don't Play Mad Scientist in the Laboratory.
- Dispose of Lab Waste Properly.
- Know What to Do With Lab Accidents.
Burette, also spelled Buret, laboratory apparatus used in quantitative chemical analysis to measure the volume of a liquid or a gas. It consists of a graduated glass tube with a stopcock (turning plug, or spigot) at one end.
How do you use a transfer pipet? To aspirate liquid - Hold the pipet vertically, gently depress the bulb, insert the tip into the liquid and gently release the bulb. Liquids should be pulled into the tube until the desired volume is reached.
To transport a measured volume of liquid
Pipette Pumps
… dispenser pipette pumps provide safe and accurate pipetting and dispensing of liquids from serological pipettes. Glass or plastic pipettes are inserted into the tapered collar and the thumbwheel is rotated for precision filling or dispensing.
