Bole’s Law Introduction Air is all around us. We breathe in the air so that our body can receive adequate supply of oxygen gas. Our lungs expand as they fill with air and take in oxygen, and relax as they release carbon dioxide. Plants in turn, use up the carbon dioxide during the process of photosynthesis to manufacture sugars. Life as we know it would not have been possible without the life-sustaining gases found in the atmosphere Like breathing, many other human activities involve gases. When air is pumped into -5_ a bicycle or automobile tire, a mixture of gases is compressed into a small volume.
Helium gas make toy balloons float. Gas used to fill rubber lifeboats and vests exerts pressure on its containers, giving them rigidity and shape. For centuries now, scientists are curious about how gases behave. Investigations on the behavior of gases mainly concern the relationship among the four important properties of gases: illume, pressure, temperature and amount in moles. This lesson introduces the relationship between volume and pressure at constant temperature, which is also known as Bole’s Law. What you will do Activity
The subscript of 1 refers to the original conditions while 2 refers to the new conditions. The figure on the right shows what happens to the volume of a sample of gas when pressure is increased while maintaining the temperature. Note the inverse relationship of pressure and volume. Figure 1. 3 Illustration of Bole’s Law Checkpoint Explain in terms of Bole’s law what happens when you alternately squeeze and release a hollow rubber ball. Answer: When you squeeze a hollow Auber ball, the volume decreases and the pressure within the ball increases. W the squeezing ceases, the volume increases and the pressure decreases within the ball.
Are you ready to experience Bole’s Law in action? Try these activities on your own or together with a friend. -8- Activity 1. 3 In this activity, you will demonstrate Bole’s Law using simple materials. You will need several small marshmallows and a plastic syringe with a diameter large enough to fit the marshmallows. You will also need the plastic cap but not the needle of the syringe for this. Remove the plunger of the syringe and put the marshmallows inside. Return the plunger allowing only a small space for the marshmallows. Place the cap tightly (you may want to use wax to seal it).
Slowly pull the plunger away and see how the marshmallows magically expand! They will return to the original size if you release the plunger. Can you explain these observations in terms of Bole’s Law? Try these Self-Test questions to check how well you understood Lesson 1 . Self-Test 1. 1 Directions: Read each item carefully and supply the required information. 1 . A certain model of a car has gas-filled shock absorbers to make the car run smoother and less “bumpy. ” Describe the gases inside the shock absorbers hen the car is full of passengers compared to when the car is empty. 2.
Which graph demonstrates Bole’s law? Vertical axis is V and horizontal axis is P a. B. C. D. 3. If the pressure on a gas is decreased by one-half, what will happen to its volume? 4. A 40 L balloon is filled with gas at 4 ATM. What will be its new volume at standard pressure of 1 ATM? 5. A gas at 30. ICC occupies 500 ml at a pressure of 1. 00 ATM. What will be its volume at a pressure of 2. 50 ATM? Key to answers on page 21 . Lesson 2. Charles’ Law Introduction In this lesson, we will investigate Charles’ Law, which relates changes in he temperature of a confined gas kept at a constant pressure to the volume of the gas.
You will be introduced to another equation that determines the variation of gas volume with change in temperature. Discussion Jacques Charles was a French chemist famous for his experiments in ballooning. Instead of hot air, he used hydrogen gas to fill balloons that could stay afloat longer and travel farther. Figure 2. 1 Jacques Charles slaw/slaw. HTML Charles’ Law states that tort a given amount tot gas at constant pressure, the volume is directly proportional to the temperature in Kelvin, V a T. Charles Law is expressed in equation form as: TIFT = TV.