Practical 7.1: Gas Tests for Oxygen and Carbon Dioxide

<p>The burning splint extinguishes quickly. (D)</p> Signup and view all the answers

<p>Oxygen. (A)</p> Signup and view all the answers

<p>Wear safety spectacles. (D)</p> Signup and view all the answers

<p>It remains colorless. (A)</p> Signup and view all the answers

<p>Observe and record the reaction immediately. (C)</p> Signup and view all the answers

<p>The gas is nitrogen. (A)</p> Signup and view all the answers

<p>Oxygen (A)</p> Signup and view all the answers

<p>Nitrogen. (C)</p> Signup and view all the answers

<p>Hydrogencarbonate indicator (B)</p> Signup and view all the answers

<p>Record the initial gas color. (A)</p> Signup and view all the answers

<p>Never directly inhale the gas. (B)</p> Signup and view all the answers

<p>The solution becomes cloudy when lime water is introduced. (A)</p> Signup and view all the answers

<p>It ensures accurate measurements. (C)</p> Signup and view all the answers

<p>Blue (C)</p> Signup and view all the answers

<p>Pink (A)</p> Signup and view all the answers

<p>Alcohol (B)</p> Signup and view all the answers

<p>Wear disposable gloves (D)</p> Signup and view all the answers

<p>Lime water (A)</p> Signup and view all the answers

<p>Turns yellow (C)</p> Signup and view all the answers

<p>Good ventilation (A)</p> Signup and view all the answers

<p>From blue to pink (A)</p> Signup and view all the answers

<p>It acts as an indicator that changes color in the presence of water vapor. (D)</p> Signup and view all the answers

<p>To prevent it from absorbing moisture from the air. (A)</p> Signup and view all the answers

<p>Test tube (C)</p> Signup and view all the answers

<p>It turns pink. (D)</p> Signup and view all the answers

<p>Touching it with bare hands. (C)</p> Signup and view all the answers

<p>To test for the presence of water vapor. (B)</p> Signup and view all the answers

<p>Absorbing nitrogen from the atmosphere. (B)</p> Signup and view all the answers

<p>Distilled water. (C)</p> Signup and view all the answers

<p>The existence of oxygen (C)</p> Signup and view all the answers

<p>The relationship between oxygen and combustion was clarified. (A)</p> Signup and view all the answers

<p>It facilitated precise measurements and observations. (B)</p> Signup and view all the answers

<p>Collaboration and competition between different scientists. (A)</p> Signup and view all the answers

<p>The theory of phlogiston was widely accepted. (B)</p> Signup and view all the answers

<p>Measuring the temperature of burning substances. (B)</p> Signup and view all the answers

<p>It unified various concepts of chemical reactions. (A)</p> Signup and view all the answers

<p>Oxygen is a key component of air essential for burning. (A)</p> Signup and view all the answers

Using a burning splint to test for oxygen. A burning splint re-ignites in oxygen.

Oxygen is a colorless, odorless gas.

A wooden splint that has been lit on fire and used to test for gases like oxygen.

A wooden splint that has had its flame blown out, leaving it glowing.

Act quickly to minimize gas escape when testing gases.

Using a gas indicator solution (e.g., limewater) to detect carbon dioxide, which causes a cloudy effect (precipitation).

A solution used as an indicator that reacts with carbon dioxide, changing the solution’s color or producing a precipitate.

Different tools (e.g., test tubes, wooden splint, gas lighter, indicators) for safety and identification of gases.

A special type of paper that changes color when it comes into contact with water vapor.

Cobalt chloride paper that has been dried out and is ready to test for water vapor. It should be blue.

Cobalt chloride paper that has absorbed water vapor and changed color to pink.

To identify oxygen, re-ignite a glowing splint by introducing it to the gas. The splint will instantly burst into flame if oxygen is present.

When carbon dioxide gas is bubbled through limewater (calcium hydroxide solution), it reacts, forming a white precipitate (calcium carbonate), making the solution cloudy.

A solution used to detect carbon dioxide. It turns from red to yellow when exposed to carbon dioxide.

Nitrogen is a colorless, odorless gas that doesn't support combustion. It's inert and doesn't react with either burning or glowing splints.

To test for nitrogen, try a burning splint. If it extinguishes, you might have nitrogen. Further testing is required to fully identify it.

A test used to identify oxygen by inserting a glowing splint into a gas. If oxygen is present, the splint will re-ignite.

Different gases have unique properties that can be utilized to identify them. This includes observing their physical properties (color, odor) and their reactivity with specific indicators.

When working with gases, it's critical to handle them safely. This includes minimizing gas escape and using appropriate indicators and equipment.

A simple test to detect the presence of water vapor. It relies on the color change of cobalt chloride paper from blue to pink when exposed to moisture.

Dry cobalt chloride paper, which is blue, turns pink when it comes into contact with water vapor.

Alcohol does not change the color of dry cobalt chloride paper. Unlike water, alcohol does not cause a color change.

One way to test for the presence of water is to observe if dry cobalt chloride paper changes from blue to pink.

Cobalt chloride paper changes color specifically in the presence of water vapor, making it a reliable indicator for water.

Start with a piece of dry cobalt chloride paper (blue). Place the paper in the area you want to test for water. Observe any color change from blue to pink.

Dry cobalt chloride paper remains blue when exposed to alcohol.

Only dry cobalt chloride paper can accurately show the color change to pink in the presence of water. Wet paper will already be pink, making testing unreliable.

Antoine Lavoisier, in the late 18th century, was the first to recognize oxygen as a distinct element. Prior to this, the nature of air and the process of burning were poorly understood.

Lavoisier investigated burning and discovered that oxygen plays a crucial role in combustion. Through his experiments, he established the concept that burning involves the reaction between a substance and oxygen.

Prior to Lavoisier's work, people believed burning was caused by a specific substance called 'phlogiston' being released during the process. They didn't know about oxygen's involvement.

Advances in technology, like the invention of accurate measuring instruments and new techniques, played a key role in the discovery of oxygen and the understanding of combustion.

Lavoisier's work completely changed the way people understood burning. It was no longer viewed as a process of releasing 'phlogiston' but rather a chemical reaction involving oxygen.

While Lavoisier was the one credited with the discovery of oxygen, other scientists like Priestley and Scheele were also exploring burning. They may have even discovered oxygen independently, but Lavoisier's experiments were more thorough and influential.

Even though one person might be recognized for a scientific discovery, it's often a result of the work and ideas of many individuals. It's a process involving both collaboration and competition.