Chemistry- Identifying Gases Flashcards
What is the appearance of Hydrogen gas (H2)
H2 is a colorless and odorless gas
Describe a test used to identify hydrogen gas.
Place a lighted splint at the mouth of the test tube containing the gas and a squeaky ‘pop’ will be heard as well as the fire will be extinguished.
What is the appearance of oxygen? / Describe the colour and smell of oxygen gas.
Oxygen is a colourless, odourless gas.
What is the appearance of carbon dioxide?
Carbon dioxide is a odourless and colourless gas.
Describe a test used to identify oxygen gas
Oxygen gas can be identified using a glowing splint. By putting the glowing splint at the mouth of a test tube containing oxygen it will relight the glowing splint
What is a test that can be used to identify Carbon dioxide gas, must include an equation.
Bubble the gas into a test tube with lime water (Calcium hydroxide) and observe a white ppt being formed of calcium carbonate
Ca(OH)2 (aq) + CO2 (g) > CaCO3(s) + H2O(l)
Upon continued bubbling, the ppt redissolves due to the formation of soluble calcium hydrogen carbonate.
CaCo3 (s) + CO2(g) + H2O (l) > Ca(HCO3)2(aq)
What is the appearance (color and odor) of ammonia gas?
Ammonia has a pungent odor and is colorless
Describe two (2) test used to identify ammonia gas
Use a moist red litmus paper and hold it in the gas, the red litmus paper will change from red to blue due to the reaction of the ammonia and the water from the litmus paper gives ammonia hydroxide which is a base.
A second test is to place a drop of concentrated hydrochloric acid on a glass rod near the gas and a white fume of ammonium chloride will be formed.
NH3 (g)+ HCL (aq)> NH4CL (aq)
Hydrogen chloride. What is the appearance?
Hydrogen chloride is a colorless gas with an acidic smell.
Describe a test that can be used to identify hydrogen chloride.
Place a drop of concentrated ammonia solution on a glass rod near the gas and a white fume of ammonium chloride will be formed. (Same equation as ammonia gas test)
Give a description of Sulphur dioxide referring to smell and appearance.
Sulfur dioxide is a colorless gas with a pungent smell.
What is a common laboratory test used to identify Sulphur dioxide?
Bubble the gas into an acidified potassium permanganate solution. MnO4^- in contact with gas will be reduced to Mn2+, changes from purple to colorless
Bubble the gas into an acidified potassium dichromate solution. The gas will reduce the Cr2O7^2- ion to Cr3+. The solution turns From orange to green
Describe chlorine gas.
Chlorine is a yellowish-green gas with a sharp odor it is also poisonous.
Describe a test used to identify Cl2(g)
use moist blue litmus paper that will turn red and then be bleached white, the chlorine gas reacts with the water to produce HCL and chloric acid
Cl2(g) + H2o(l)> HCL(aq) + HClO(aq)
Chloric acid oxidizes the red litmus paper turning it colourless.
Nitrogen dioxide. Describe properties.
Nitrogen dioxide is a very detectable brown gas and has a sharp irritating odor.
