CHEM 103 Lab Quiz 1 exam 2023 with 100% correct answers

What is the purpose of the litmus paper test? It is used to see if the gas reacts with water to generate an acid or base. How do you test a gas to see if it supports combustion? You use a glowing splint by igniting it, blowing out the flame, and putting the glowing splint on the neck of the bottle as gas is being generated. If the splint glows or pops, then the gas does support combustion. The production of a gas (or gases) demonstrates which kind of change, physical or chemical? Chemical because they are creating a new product. Why do some portions of the experiment have to be carried out in a fume hood? Some of the gases produced are toxic to humans. Which gas, or gases, will be colored? Nitrogen Dioxide What will H2S gas smell like? Rotten egg Review your observations for each gas prepared. In the class of elements did the gases have any trait in common? The oxides? The hydrides? Are there any common traits among the three classes of gases? Explain. The oxides had no odor and did not support combustion. The hydrides had smells while most others did not. Nitrogen and oxygen were both strong in effervescence. None of the groups had anything in common. Which of the prepared gases may contribute to acid rain? Sulfur Dioxide and Nitrogen Dioxide. Which of the prepared gases are considered air pollutants? Are they acidic or basic? What are the sources of these gases? The gases considered air pollutants are sulfur dioxide, nitrogen dioxide, hydrogen sulfide, and ammonia (when in high levels). All of the gases are acids, except ammonia (a base). They are made through burning fossil fuels, coal, and lead. Look at the chemical reactions for the gases you prepared. What molecule is almost always formed along with the gases? Water (H2O) List some physical properties of helium, copper, and rubbing alcohol. Helium: colorless, odorless, low density. Copper: shiny, reddish brown, malleable. Rubbing alcohol: colorless, strong odor, evaporates quickly.