is carbon dioxide and or hydrogen in a clean empty test tube
If a test tube is clean and dry, then there should be nothing in it.
You can test for oxygen by placing a glowing splint (not lit but not out) into the test tube where you think oxygen is present. If the splint relights, that means that it is oxygen. If this doesn't happen, then in your case it will be nitrogen.
You stated that carbon dioxide and nitrogen are present, but you did not mention oxygen. Nothing burns without oxygen . . . If you expose limewater to carbon dioxide, it will get cloudy, but will not if you expose it to nitrogen.
One way to distinguish between nitrogen oxide and oxygen is by using a glowing splint test. When a glowing splint is introduced to a gas sample, oxygen will relight the splint due to its ability to support combustion, while nitrogen oxide will not. Additionally, nitrogen oxide can be detected using a brown ring test with iron(II) sulfate and sulfuric acid, where a brown ring forms at the junction of the two layers if nitrogen oxide is present.
The test for oxygen is to insert a glowing splint into a test tube and see if it glows brighter or re-ignites.
To remove oxygen from a test tube, one method is to displace it with an inert gas, such as nitrogen or argon. By flushing the test tube with the inert gas, the oxygen is pushed out. Another method is to create a vacuum inside the test tube to remove the oxygen. This can be done using a vacuum pump or a syringe to pull the air out of the tube.
Nitrogen dioxide and oxygen are released.
The CPK color convention for test tubes typically assigns carbon with the color black, oxygen with red, and nitrogen with blue.
Oxygen.... Thought it was Nitrogen, but ti's oxygen, got it wrong on test, right answer is oxygen.
No, in fact most early spacecraft the test animals, astronauts, or cosmonauts breathed pure oxygen. This was stopped after the Apollo-1 fire, which was attributed to defective wiring and a pure oxygen atmosphere. After that some nitrogen was added as a safety feature against fire.
Just try lighting up a match, if it burns its a proof that oxygen is present...! But, do remember lighting up a match will start using the present oxygen, so if you think you'll have a limited amount of it available...be wise to put off the flame ASAP.
When nitrogen is present in a sodium fusion test, it forms sodium azide (NaN3), which upon heating decomposes into sodium, nitrogen gas, and atomic nitrogen. The atomic nitrogen emits blue light when it reacts with the oxygen in the air, giving the characteristic blue color to the flame during the sodium fusion test.