What is Boyle's law: Definition and 41 Discussions

Boyle's law, also referred to as the Boyle–Mariotte law, or Mariotte's law (especially in France), is an experimental gas law that describes how the pressure of a gas tends to decrease as the volume of the container increases. A modern statement of Boyle's law is:

The absolute pressure exerted by a given mass of an ideal gas is inversely proportional to the volume it occupies if the temperature and amount of gas remain unchanged within a closed system.

Mathematically, Boyle's law can be stated as:


where P is the pressure of the gas, V is the volume of the gas, and k is a constant.
The equation states that the product of pressure and volume is a constant for a given mass of confined gas and this holds as long as the temperature is constant. For comparing the same substance under two different sets of conditions, the law can be usefully expressed as:











{\displaystyle P_{1}V_{1}=P_{2}V_{2}.}
This equation shows that, as volume increases, the pressure of the gas decreases in proportion. Similarly, as volume decreases, the pressure of the gas increases. The law was named after chemist and physicist Robert Boyle, who published the original law in 1662.

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  1. patric44

    Percentage change in the density of a gas

    Hi all, in this question i was asked to find the percentage change in the density, my approach was as following, first i find the change in volume due to putting the gas into the other vessel as: $$ P_{1}V_{1}=P_{2}V_{2}\;\; → \;\;V_{2}=\frac{P_{1}}{P_{2}}V_{1} $$ now i use $$...
  2. blinkz303

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    I am currently working on a project trying to calculate leak rate and fluid loss from pressurised vessels filled with water over a time period of 30 minutes. So far I have used the Boyles Law which assumes that PV/T = constant which gets us P1 * V1 = P2 * V2 and PdV+VdP = 0 I formed this over to...
  3. L

    Engineering Find the volume of a gas using Boyle's law

    Is this right go confused with the 37 degrees Q) pV = Constant pressure of a gas is ‘10’ (kPa) and the constant ‘37 degrees celcus’ = ‘0.6’, calculate the volume that the gas. pV = C C/p = V 0.6/10 = C V = 0.06
  4. WMDhamnekar

    MHB Exploring Robert Boyle's Law: Pressure and Volume of CO2

    Robert Boyle's law states that at constant temperature, the pressure of fixed amount ( i-e number of moles n) of gas varies inversely with its volume. Mathematically, it can be written as $p ∝ \frac1V $(at constant T and n) $\Rightarrow p = k_1 \times \frac1V $ where $k_1$is a proportionality...
  5. rjomega

    Effect on Volume of a Change in the Pressure of Compressible Gas

    Will the available Volume of oxygen gas for use of patients increase when the pressure decreases from 12.4 MPa to 500 KPa? Is using boyle's law the right way to calculate the available volume?
  6. H

    B Boyle's law vs the Venturi effect

    So this is something I been thinking about. In venturi principle when a fluid or gas is moving across a tube when it is constricted the fluid has increased velocity. Because it in constriction the pressure goes down. But in Boyle law if volume is decreased the pressure goes up. So in the...
  7. nmsurobert

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    When using a Boyle's Law Apparatus, pressure applied to the plunger can be calculated by knowing the mass of the object on the plunger and the area of the plunger. P = F/A. The change of pressure inside the cylinder can be calculated using Boyles Law, P1V1 = P2V2 Should the value for the...
  8. patric44

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    Homework Statement a Basin contains water , a beaker is put upside down to a depth of 3m inside it , if the volume of the beaker is 250 cm^3 . and its C.S area = 200 cm2 calculate the length of the water column which rises inside the baker , supposed that their is no air leakage from the...
  9. Glurth

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    I have a simulation I'm trying out (for fun). A self-gravitating ball of gas, in deep space. (The sim uses a fixed-time-step for each iteration.) I'd like to use Boyles Ideal gas law, the force of gravity, and energy as internal heat. (I don't want to touch enthalpy unless I don't realize...
  10. D

    Boyle's law pressure calculation

    Homework Statement An pillow is inflated with an pressure of let's say 20 hPa. Afterwards we place a weight of 10 Kg on the pillow, what is the pressure increase within the pillow? P athmosthere = 1013 hPa P cushion = 1013 + 20 = 1033 hPa m = 10 Kg g = 9.81 m/s^2 Amount of air in the pillow...
  11. K

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  12. R

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    If I have a tank of volume V, pressure P, and temperature T, what is the most effective way to determine the volume flow rate if I were to suddenly allow the air to discharge through a hose? My first thought was that I could use Boyle's Law to determine the compressed volume of air in the tank...
  13. Z

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  14. Y

    IGCSE Physics Boyle's law question

    Homework Statement The helium in the cylinder has a volume of 6.0 × 10^–3 m3^-1 (0.0060 m^3) and is at a pressure of 2.75 × 10^6 Pa. (i) The pressure of helium in each balloon is 1.1 × 10^5 Pa. The volume of helium in an inflated balloon is 3.0 × 10^–3 (0.0030 m3). The temperature of the...
  15. G

    How Do I Determine the Change in Entropy of the System?

    Homework Statement Determine ΔSsys when 3.0 mol of an ideal gas at 25°C and 1 atm is heatedd to 125°C and expanded to 5 atm. Rationalize the sign of ΔSsys. Homework Equations State Function: dS = (dU)/T + (PdV)/T State Function for Entropy of Ideal Gas: dS = (CV,mdT)/T + (nRdV)/V Ideal gas...
  16. A

    What is the independent variable in Boyle's Law?

    I asked my teacher, and I was told that volume is the independent variable, and that pressure is dependent. The textbook I'm using said the same thing. After looking up some graphs of the law, I found that both pressure and volume were used as independent variables. It seems counter-intuitive...
  17. 2

    Confused about Boyle's Law, Charles' Law and the pressure Law?

    In my textbook, it says that pV=C (Boyle's Law), V/T=C (Charle's Law) and that P/T=C (pressure Law). The problem is that I cannot see how the first two equations combine to give the last one. If I divide the first equation by the second, I get that pT=C, which certainly is not the same as the...
  18. Entanglement

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    Boyle's law states that the product of the pressure and the volume of a gas is Constant at a constant temperature, that means if pressure increase two times the volume decrease to half it's value "as long as the temperature is constant". How is the pressure increased and the temperature is kept...
  19. L

    Exploring the Relationship Between Boyle's Law and Plate Tectonics

    I have been trying to find out of Boyle's Law and plate tectonics are in any way shape or form related. Are they? If they are not, is there a way I can relate their movement to physics?
  20. S

    Boyle's Law and collisions by the ideal gas molecules on the container

    When we use Boyle's Law it means that as pressure increases the volume of the container would decrease. In my notes they stated that if I were to halve the volume there would be two times the number of collisions per second which implies that the force exerted is doubled. But why is this so? I...
  21. C

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    Hey guys, I was just wondering if you could help me on this quick question I have. Homework Statement A student does an experiment to investigate Boyle's Law by adding masses onto the bottom of an upside down syringe and measuring the length of the gas column in the syringe. Force is...
  22. F

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    I've curious about how an air conditioner or refrigerator make's cold air. I've read two different descriptions how cold is "made", or how heat is removed from a system. Some descriptions I've read say that air conditioners use expanding gas in it's coils, hence the use of Boyle's law. Other...
  23. L

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    A narrow uniform glass tube contains air enclosed by a thread of mercury 15cm long. When the tube is held vertically, with the closed end at the bottom,the air column is 20.0cm long, but when it is held horizontally the air column is 24.0cm long. Calculate the atmospheric pressure. I...
  24. K

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  25. B

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  26. M

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    Hi, I was working through a past exam paper when I came across a Boyle's Law question in which the answer to the second part confused me. I will write the question, part one and its solution and the second part. Here is the question : A rigid cylinder contains 0.08 m^3 of helium gas at a...
  27. H

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    Hello, I am Year 10 student and would like to get help on the question below based on Boyle's Law. A piston with a block of mass 120 grams placed on it traps 200cm³ of air in a container. When the block is removed, the volume becomes 250cm³. Find the mass of the piston. In the question...
  28. M

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  29. D

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    Homework Statement Okay... everywhere i look, it keeps talking about Boyle's Law applied to THE SAME gas! It's so frustrating and retarded! I get it, p1V1 = p2V2. Yay... I didn't even need to look THAT up! But my question is, how do you compare 2 different (ideal) gases?? It seems like...
  30. 9

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  31. M

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  32. A

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    Homework Statement An empty barometer tube,1m long is lowered vertically, mouth downwards, into a tank of water. what will be the depth of the top of the tube when the water has risen 20cm inside the tube?(atmospheric pressure may be assumed to be equal to 10.4m head of water) Homework...
  33. S

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  34. C

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    This is a very curious situation. I have a large water tank on the top of a hill. It supplies a gravity fed water system that works fine. There is an under ground pipe with one end A in the bottom of the tank. The other end E is about 80 feet below A, and has a faucet. None of the pipe is...
  35. R

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  36. Amith2006

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    Sir, I have a have a doubt in the following problem: # A volume V of air saturated with water vapour exerts a pressure P. If the volume is made V/2 isothermally, what will be the final pressure? I solved it using Boyle's law but that answer which is "2P" doesn't agree with the answer...
  37. T

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    Hi Everyone, first semester Physics student here and we are working on a tough lab this week, having to do with Boyle's Law...argghh! :cry: Anyways, here is my problem, and trying to work through it to obtain the correct answer...but it is stumping me! The question as follows: 1...
  38. Z

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    According to boyle's law, P1V1=P2V2 (without temp. change) right? Therefore when 10cm^3 of oxygen is compresssed into a 5 cm^3 container , the pressure would double right? I believe that the pressure the molecules exerts on the container is due to the force that the molecules exert when they...
  39. N

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    So i looked up Boyle's and it said PV = C P= pressure V= Volume C= constant so my question is Suppose 38 pounds of books were balanced on a syringe plunger with a cross-section area of 0.45 in^2? A) how much pressure would just the books exert on the trapped air sample...
  40. F

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    Hello everyone! I have some questions here to ask... I hope anyone could help me here. Here are the following. 1. How would the presence of air bubbles or water in mercury affect the results in a "J-tube" experiment? 2. Why does food cook faster in a pressure cooker than in an...
  41. F

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    Hello guys, I got some problems again. Will you be able to help me? What is the difference between the absolute pressure and gauge presure? Why is the absolute pressure plotted vs the length of the column of the trapped air instead of the volume of trapped air in the J-Tube?