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What is the proper technique in heating a liquid in a test tube?
Correct technique It is important to heat the tube gently and uniformly. Use a medium blue flame and move the test tube around in the flame to heat the entire surface of the tube as evenly as possible. This is important to minimize bumping and cracking.
What happens when heating a substance?
Heating a substance makes the molecules move faster. Cooling a substance makes the molecules move slower.
What is heating in laboratory techniques?
In the laboratory you will be required to heat chemicals in dissolution of a solid, promotion of reaction (reflux), distillation of pure compounds and mixtures, extraction, coagulation of precipitates, drying solid compounds, etc.
Is the least important mode of heat?
Radiation is the least important mode of heat transport in the Earth. The process of heat exchange between the Sun and the Earth, through radiation, controls the temperatures at the Earth’s surface.
What happens to a solid when heat is added?
When a solid is heated the particles gain energy and start to vibrate faster and faster. Initially the structure is gradually weakened which has the effect of expanding the solid. Further heating provides more energy until the particles start to break free of the structure.
How do you heat a substance in a test tube?
Always point the test tube away from any other person in the lab. Heat the test tube being held at an angle so there is a way for the gases produced to escape safely. Heat the test tube at the top of the solution not the bottom where a gas bubble can cause an explosion.
What do you need to know about heating in the laboratory?
Heating In the laboratory you will be required to heat chemicals in dissolution of a solid, promotion of reaction (reflux), distillation of pure compounds and mixtures, extraction, coagulation of precipitates, drying solid compounds, etc. Your choice of heat source depends upon several factors:
How do you heat a gas burner in a laboratory?
Open the collar to produce a hot blue flame and adjust the gas flow to give the required size of flame. If your work is interrupted, close the collar a little to produce a luminous flame. Finally, when the operations are complete, turn off the gas and do not pick up the burner by the barrel, or put it into a cupboard, until it has cooled.
Which is the most versatile heat source in the laboratory?
Hotplates are perhaps the most versatile heat source in the laboratory and can be used to heat beakers, Erlenmeyer flasks, and various hot baths (water, sand, and oil baths). They can also be used to develop stained TLC plates. 1.4F: Steam Baths A steam bath is a relatively safe way to heat flammable organic liquids.