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because convection currents are caused by the liquid being heated, becoming less dense due to increased kinetic energy and rising. if you are heating the top of the test tube, there is nowhere for them to 'rise' to, so no current is formed, as they do not reach a place where they cool and sink to the bottom. thus convection currents are only formed when heating the bottom of a test tube.
What else can I help you with?
Why is a vessel containing liquid always heated from below rather than from the sides?
This is due to the type of heat transfer which takes place. In a liquid (or a fluid in general), heat is transferred by convection, in which the BOTTOM part of the liquid gets heated, becomes less dense, moves upwards and is replaced by cold and denser liquid from the top. This is why a liquid is heated from below. By the way, water is a poor conductor of heat, which means that if heated at the top, no convection would take place and little conduction would take place meaning that the whole of the liquid would not become hot. Cold denser water would remain at the bottom and hot less dense water at the top.
What happen when a test tube of liquid is heated improperly?
- the test tube may break- the liquid can be spread outside
When bright red mercury (II) oxide is heated in a test tube oxygen gas is evolved and droplets of liquid mercury condense at the cooler top of the test tube.?
Yes, it is correct.
What happened when you placed a lighted match near the test tube?
The heat from the lighted match caused the liquid in the test tube to heat up. If the liquid was flammable, it may have caught on fire. However, if the liquid was not flammable, it would have simply heated up and there may have been no other visible changes.
What exactly are science test tubes?
Science test tubes; generally made of pyrex to reduce breakage, are tubual containers often used in experiments. They can be heated, and cooled, and can you can use liquid or powder substances in them.
What is the source of liquid droplets seen on the inner upper side of the test tube during the heating process?
The liquid droplets on the inner upper side of the test tube are likely due to condensation. As the test tube is heated, the air inside expands and rises, coming into contact with the cooler upper side of the test tube, causing it to condense into droplets.
What happen ton sulphar when slightly heated in test tube by a Bunsen burner?
When sulphur is heated in the test tube in the absence of air the sulphur will break down and form a red-brown liquid. If oxygen comes into play sulphur dioxide is produced, however you should not that sulphur dioxide is a highly toxic gas and should only be produced in small amounts under a fume hood.
What is a measure of liquidity?
the two ratios that measure liquidity is acid test and current ratio. the acid test ratio is current assets- stock/ current liabilities the current ratio is current assets/ current liabilities
How could you show that water is given off when epsom salts are heated?
When epsom salts are heated, water vapor is produced as a byproduct. This can be shown by heating epsom salts in a test tube and collecting the water vapor produced in a cooled condenser, where it will condense back into liquid water. The presence of liquid water in the condenser confirms that water is given off during the heating of epsom salts.
How do you zero phase current tranformer test?
How do you zero phase current transformer test
What changes occur inside the test tube when you heat water?
we can consider following observations: - the glass tube will expand internally - the water inside will expand - convection current will twke place till heat is stopped - bubbles may be seen because some water in liquid form may change in gaseous state but still remain trapped in water - temperature will rise
What happen if heat is applied at the bottom of a test tube containing liquid on it?
You should never point the open end of the test tube when heating liquids toward yourself or others for your own safety. Liquids inside the test tube when heating may release some gases and might affect someone when you point the open end of the test tube to them. when heating the test tubes, position it diagonally and move it slowly sidewards so we can prevent cracking or breaking of the test tubes if directly positioned on fire.
