The volume of the balloon is 0.030m ^3. (Consider what happens if we compress a portion of air with a piston -- say, a bicycle pump. MathJax reference. PV &= nRT \\ Enjoying (??) How to prove that the supernatural or paranormal doesn't exist? Rent the Right Size of Helium Tank. And although this data is readily available, as we have found, it is not all that accurate. Connect and share knowledge within a single location that is structured and easy to search. Making educational experiences better for everyone. (326g) *Because the filling and usage of display balloons is beyond our control, no performance or longevity guarantee can be made. A balloon inflated with three breaths of air has a volume of 1.7 L. At the same temperature and pressure, what is the volume of the balloon if five more same-sized breaths are added to the balloon? Then, under water, let the air escape into an inverted bottle that has been filled with water. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. After it is released, it rises to a location where the pressure is 0.720 atm and the temperature is $-12.0^{\circ} \mathrm{C}$. Hydrogen weighs just 0.08988 grams per liter. V &= \frac{m_\text{payload}}{\rho - \frac{PM_h}{RT}} \\ Use * as a wildcard for partial matches, or enclose the search string in double quotes for an exact match. This is because helium is less dense. What video game is Charlie playing in Poker Face S01E07? No helium leaves the balloon. However, they need to be checked by the moderator before being published. But then there would need to be infinitely much of it, which is absurd in conflict with observations: It is well known that the density in space approaches zero, and since the atmosphere is not a liquid, it has no distinct upper edge, so its density must decrease gradually as we move up. Question #283199. National Institute of Standards and Technology; U.S. Department of Commerce; 1401 Constitution Ave N.W. "We, who've been connected by blood to Prussia's throne and people since Dppel". Archimedes' principle allows you to calculate the upthrust on an object in a fluid (a liquid or gas). Very interesting problem, and a nice result at the end too! a) If 1g, A glass U-tube of uniform cross-sectional area is sealed at one end. They have fewer electrons, protons and neutrons than nitrogen atoms do, and that makes them lighter (the approximate atomic weight of hydrogen is 1, helium is 4 and nitrogen is 14). Furthermore, I also have noticed that because of the lower pressure higher in the atmosphere helium expands and balloon seems filled up. If an air mass started to rise then contract due to cooling, that would be the end of that convection event. What is precisely the reason that a helium balloon ascends? \rho &= \frac{m_\text{air}}{V} \\ There are three certainties in this world: Death, Taxes and Homework Assignments. The mass and volume of helium in the balloon remained constant. Is a PhD visitor considered as a visiting scholar? Use MathJax to format equations. Helium balloons work by the same law of buoyancy. If you buy one at the circus or fair, you can hold its string and it will ride along above you. Get tips on science and chemistry with help from an experienced educator in this free video series. Volume of Helium in Different Sizes. What is the correct way to screw wall and ceiling drywalls? Keep up with the worlds newest programming trends. Now, $\pu{25 km}$ means that it reaches the first part of the stratosphere, with temperatures of $\pu{-60 ^\circ C}$, that gradually increase until $\pu{0 ^\circ C}$ at $\pu{50 km}$. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. Density of Helium = .18 kg/m 3. How do I align things in the following tabular environment? Since the balloon's volume is not changing, we know that the outside pressure on the balloon is balanced . 4,186 cubic feet * 28.2 grams/cubic feet = 118,064 grams. Calculating probabilities from d6 dice pool (Degenesis rules for botches and triggers). If you take the same volume of air and helium and weigh them on a scale, the helium would weigh less. )What distance does the ga, In case of average velocity a body may followStraight pathCurved pathVariable motionAll of them, A cart is at x = 5.25m and time t = 0. What is its, A steel thick-walled gas cylinder used for storing compressed air is fitted with a safety valve whi, 2. Chris C. ; Washington, DC 20230. About Helium. It is present in all stars. Your physics assignments can be a real challenge, and the due date can be really close feel free to use our assistance and get the desired result. When helium filled balloons are handed out at public events, they usually come with a piece of string or ribbon attached. And how much helium do you need according to the mass that the balloon has to carry? How high will a party balloon filled with helium go? Divide by 448 -- the number of grams in a pound -- to determine the number of pounds it can lift. A 2lb ballon of helium, having displaced a larger volume of air, will have more lift. A balloon is a flexible bag that can be inflated with a gas, such as helium, hydrogen, nitrous oxide, oxygen, and air.For special tasks, balloons can be filled with smoke, liquid water, granular media (e.g. It only takes a minute to sign up. Steps to complete the problem: List all of the variables given. One balloon contains 1.0 g helium. (339g) 36 inch confetti-filled. Our experts will gladly share their knowledge and help you with programming projects. It only takes a minute to sign up. What video game is Charlie playing in Poker Face S01E07? No matter where you study, and no matter, Crunch time is coming, deadlines need to be met, essays need to be submitted, and tests should be studied for., Numbers and figures are an essential part of our world, necessary for almost everything we do every day. Latex & Chloroprene Balloon Qualatex Bubbles Stretchy Plastic Balloons Qualatex Helium Chart Avg. The following chart breaks down nearly a dozen different sizes of helium cylinders. So We want a volume of helium such that it's mass is LESS than that of air by an amount equal to the mass of. \end{align}, $$V = \frac{m_\text{payload}RT}{P(M_a - M_h)} \tag{2}\label{2}.$$. Because helium is lighter that air, a helium balloon rises, just as an air bubble rises in more dense water. The buoyant force will be the weight of air that it displaces because that's Archimedes principle, and the weight of the air displaced will be the mass of the air times g.So let's create an expression for the mass of the air in terms of volume because we know the . About Helium; Helium weighs 0.0001785 gram per cubic centimeter or 0.1785 kilogram per cubic meter, i.e. Figure 2: Balloon parameters for a (upper) 1200 gram balloon and (lower) 1500 gram balloon. At room temperature (20C), its internal pressure is 1.08 atm. In this edition of HowStuffWorks, you'll find out all . ft. Average Float Time 18 - 24 Hours + Ultra Hi-Float 1 - 4 Weeks High altitude products vary by elevation and weather conditions. Let the volume of helium in the balloon be $V$. We are now in a position to calculate how much helium we need! However, do we need any density measurement at all? Explain why the pressure exerted by the helium inside the balloon would increase. That is a. Learn more about our help with Assignments: Thank you! Why are Suriname, Belize, and Guinea-Bissau classified as "Small Island Developing States"? Volume of the selected item is calculated using its density and entered weight. Science Chemistry 9. Assuming that no helium escapes from the balloon in that time, will the balloon have a larger volume than, a smaller volume than, or the same volume as that it had on the previous day? This equation, Equation \ref{2}, is superior to Equation \ref{1}. the temperature of the balloon is increased to 38.0'c as it expands to a volume of 998 l, the pressure remaining constant. Assume the density of air is 1.28 kg/m3 and the density of helium in the balloon is 0.18 kg/m3. And how much helium do you need according to the mass that the balloon has to carry? All Qualatex latex balloons are helium-weight quality and are manufactured in the USA or Canada from 100% natural, biodegradable latex. Most questions answered within 4 hours. How many moles of helium gas does the second balloon contain? If you let go of the string, it will fly away until you can't see it anymore. Doubling the cube, field extensions and minimal polynoms, ERROR: CREATE MATERIALIZED VIEW WITH DATA cannot be executed from a function. The ideal gas law describes how the volume of a gas varies with amount, in mol, of gas particles, pressure, and temperature. The volume of the balloon is 0.030m ^3. If you preorder a special airline meal (e.g. But do we need to use a density value at all? What is the volume of the balloon under these conditions? Learn more about Stack Overflow the company, and our products. 11.5 oz. Measure the volume of helium in a balloon with help from an experienced educator in this free video clip.Expert: Robin HigginsFilmmaker: bjorn wildeSeries Description: Science and chemistry are directly related to our lives in a number of interesting ways. This means that the weight of air displaced by the balloon, which Archimedes' principle says is the upthrust, is, $$W_\text{air displaced} = B = V\rho g.$$. 35,000 worksheets, games, and lesson plans, Spanish-English dictionary, translator, and learning, a Question Time to Burst: 120 min. (without it being tied). Take into account that normal atmospheric pressure at sea level is also about 1.1 x 10^5 Pa. 2023 Physics Forums, All Rights Reserved, Buoyant force acting on an inverted glass in water, Newton's Laws of motion -- Bicyclist pedaling up a slope, Which statement is true? Can airtags be tracked from an iMac desktop, with no iPhone? The best answers are voted up and rise to the top, Not the answer you're looking for? Anagram is the worlds largest manufacturer of foil balloons for every occasion; 18-inch, large shapes, singing, recordable, licensed characters, custom, decorator and other specialty balloons /> supplies, kids birthday party, kids parties, decoration party, baby shower decorations, ballons, balloon shop, party decor, helium balloon, party balloons, helium balloons, latex balloons, party . $$n = \frac{PV}{RT} = \frac{101 \times 10^3 \times 4.71}{8.314 \times 288.2} = 199\text{mol}.$$. The temperature of the air is 0C and the atmospheric pressure is 1.00 atm. 1.0 g 4.0 g d. 5.0 g e. 20. g a. Weod 0.25mol dog I mol . ft. Average Float Time 30+ Hours + Ultra Hi-Float 3 - 7 Weeks 11" Helium Capacity.5 cu. Also, if the density were the same everywhere, air at sea level would not be compressed by the weight of the atmosphere above us, which is also absurd. for any assignment or question with DETAILED EXPLANATIONS! And pressure is the average force the molecules exert on the walls of the vessel. Your physics assignments can be a real challenge, and the due date can be really close feel free to use our assistance and get the desired result. Note that this assumes the air behaves ideally (obeys $PV = nRT$), and, as we said before, the balloon exerts no additional pressure on the helium gas (if we had a metal balloon, the buoyancy would decrease with altitude of course since the volume of helium would be fixed but the air density would be decreasing). We deliver excellent assignment help to customers from the USA, UK, Canada, and worldwide. Asking for help, clarification, or responding to other answers. Also: while the trend of the pressure is quite logical, that of temperature is caused by complex interations (eg: sun rays that heat particles). 15 cu ft (.425m3) 3-5 days. 9. PV &= nRT \\ When you blow up a balloon, you sense a relatively high resistance at first. The calculator below can be used to estimate the density and specific weight of helium at given temperature and pressure. Last accessed: 29 August 2020 (nist.gov). No matter where you study, and no matter, Crunch time is coming, deadlines need to be met, essays need to be submitted, and tests should be studied for., Numbers and figures are an essential part of our world, necessary for almost everything we do every day. Thanks to the ideal gas law, the volume of the balloon doesn't really depend on the fact that the gas inside is helium in particular. Adding helium to a balloon increased its volume from 315.0 mL to 2.199 L. If the final number of moles of helium in the balloon is 26.9 mol, what was the initial number of moles of helium in the balloon? The volume of helium in an inflated balloon is 3.0 10^-3 (0.0030 m3). Although not used much anymore, hydrogen balloons were once quite popular. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. , where k is a constant for any given temperature and pressure. By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. vegan) just to try it, does this inconvenience the caterers and staff? han LooL The barrel of the pump has a wor, Neon is a monatomic gas, in which inter-molecular forces are extremely weak. Seriously, it is only slightly higher than atmospheric pressure. Heating the gas, we increase the speed of its molecules. As I said earlier, the pressure inside the balloon at a particular altitude will be basically the same as the atmospheric pressure if we ignore any additional surface tension from the balloon itself and think of it more like a plastic bag than a stretchy elastic balloon. 1. The temperature of the helium in the balloon was increased. The difference between the phonemes /p/ and /b/ in Japanese. The difference is not as great as it is between water and air (a liter of water weighs about 1,000 grams, while a liter of air weighs about 1 gram), but it is significant. Pressure Cooker at High Altitudes and Low Altitudes, Dissociation of phosphorus pentachloride in gas syringe, "We, who've been connected by blood to Prussia's throne and people since Dppel", Theoretically Correct vs Practical Notation. This explains why blimps and balloons are generally quite large -- they have to displace a lot of air to float. On a hot day, a party balloon is filled with helium. Why is this sentence from The Great Gatsby grammatical? The temperature of the helium in the balloon was increased. We can now simplify Equation \ref{1} greatly: \begin{align} HELIUM & WEIGHT CHART We deliver excellent assignment help to customers from the USA, UK, Canada, and worldwide. Divide by 448 -- the number of grams in a pound . answered 04/17/20. We've added a "Necessary cookies only" option to the cookie consent popup. Stack Exchange network consists of 181 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers. The number of moles is 2.6 m o l and the mass of the helium is 10.4 g. Is it correct to use "the" before "materials used in making buildings are"? What is the lifting force of in kN for a 10 m diameter spherical balloon with helium inside at 101 kPa and 320 K surrounded by air at 101 kPa and 298.15 K? The helium in the cylinder has a volume of 6.0 10 3 m 3 (0.0060 m 3) and is at a pressure of 2.75 10 6 P a. Thus, expressing "P_2", obtain: for any assignment or question with DETAILED EXPLANATIONS! It depends on the size of the balloon. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. Question: A helium balloon, assumed to be a perfect sphere, has a radius of 24.0 cm. You should be able to calculate the volume of helium at high and low altitudes by searching for the pressures and temperatures at those locations. Note that the pressure was converted from kPa to Pa, and the molar mass from gmol$^{-1}$ to kgmol$^{-1}$. A 12-liter balloon contains 0.52 moles of helium gas. In this modified thought experiment, the density of the gas inside the balloon is exactly the same as the density of the surrounding air, assuming that both pressure and temperature are equalized. It is connected to a container of volume 225 cm3, c. This physics video tutorial explains how to solve the helium balloon problem. density of helium is equal to 0.1785 . Please copy/paste the following text to properly cite this HowStuffWorks.com article: Marshall Brain How is Jesus " " (Luke 1:32 NAS28) different from a prophet (, Luke 1:76 NAS28)? \implies n &= \frac{PV}{RT} Stack Exchange network consists of 181 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers. Balloon is compressed at a constant temperature causing the volume to decrease to 0.025m^3. That is 14.7 PSI more or less. Thanks to the ideal gas law, the volume of the balloon doesn't really depend on the fact that the gas inside is helium in particular. Over time, however, the helium will leak from the balloon and the balloon will shrink. But it will still weigh 2lbs (+Ballon) No, I'm not confusing that. There is something incredibly neat about helium balloons! We know the molar mass of air (an average molar mass as it is a mixture of different compounds) to be $M_a = 28.97\text g \text{mol}^{-1}$. Note that the gas pressure is of the helium in the balloon. But helium is lighter that air. In this case, the helium balloon that you hold by a string is floating in a "pool" of air (when you stand underwater at the bottom of a swimming pool, you are standing in a "pool of water" maybe 10 feet deep -- when you stand in an open field you are standing at the bottom of a "pool of air" that is many miles deep). No density value required. It's because the hydrogen and helium atoms are lighter than a nitrogen atom. MathJax reference. Key Takeaways: Helium Balloons. We can now use the atmospheric conditions at $30$km, with this amount of gas, to see the volume up there: $$V = \frac{nRT}{P} = \frac{199\times 8.314 \times 226.9}{1.20 \times 10^3} = 312\text m^3.$$. Note: The results calculated with the helium calculator are only approximate values and may deviate from reality due to the influence of . This is College Physics Answers with Shaun Dychko. Are there tables of wastage rates for different fruit and veg? How many moles in 100 grams of Helium? Cube the radius (multiply it by itself twice: r*r*r), multiply by 4/3 and then multiply by Pi. 0.00010318 ounce [oz] of Helium fits into 1 cubic inch. ncdu: What's going on with this second size column? One cubic foot of helium will lift about 28.2 grams, so multiply the volume of the balloon by 28.2. I realize as balloons go higher, the atmospheric pressure decreases, doing less to counteract the force of the gas particles pushing against the inner walls of the balloon. Calculate the new pressure in the balloon. Special Offer on Antivirus Software From HowStuffWorks and TotalAV Security. Therefore, if you were to fill a 1-liter soda bottle full of helium, the bottle would weigh about 1 gram less than the same bottle filled with air. 0.336 L volume of the balloon? In this case, since the volume and molar quantity of the gas are changing, you need to solve the following equation: n1 20.4 mol, or n1 = (20.4)(0.8323) 4.266. Number mol. In this case, the buoyancy is equal to the weight of helium plus that of the balloon (and the cord). How to keep a helium balloon between 1 to 5 meters above ground? The N, R and P do not change in helium and hot air balloons, only volume and temperature. "P_2 = \\dfrac{P_1V_1}{V_2}\\\\\nP_2 = \\dfrac{100000Pa\\cdot 0.030m^3}{0.025m^3} = 120000Pa", Two protons in an atomic nucleus are typically separated by a distance of 2 x 10-15 m. The electric, How much work is done on a table pulled 5m by a force of 30N at an angle of 60 above the horizonta, A gardener walks in a flower garden as illustrated in the figure below. Is the reason why the volume nonetheless increases because the pressure outside decreases faster than the temperature? The balloon is released and it rises to an altitude of 30,000 i. Why are physically impossible and logically impossible concepts considered separate in terms of probability? The weight of the envelope of the balloon is46.5N and the volume of the helium when the balloon is fully inflated is31.5m3. sand, flour or rice), or light sources.Modern day balloons are made from materials such as rubber, latex, polychloroprene, or a nylon fabric, and can come in many different colors. I start from the Buoyancy Formula: Making statements based on opinion; back them up with references or personal experience. Last accessed: 29 August 2020 (nist.gov). The most straightforward approach would be to sub-in the conditions at an altitude of $30$km to Equation \ref{1}. The radius of the balloon (when filled) is R = 4.9 m. The total mass of the empty balloon and basket is mb = 125 kg and the total volume is Vb = 0.059 m3. Browse other questions tagged, Start here for a quick overview of the site, Detailed answers to any questions you might have, Discuss the workings and policies of this site. = 6.00 g 4.00 g/mol = 1.50 mol. Where does this (supposedly) Gibson quote come from? Weigh the full bottle, then again with the air that has escaped from the balloon. Physics Stack Exchange is a question and answer site for active researchers, academics and students of physics. That was very helpful! (Because gas molecules interact with each other in ways different from purely elastic collision, gases do . Nitrogen weighs 1.2506 grams per liter, and since nitrogen makes up about 80 percent of the air we breathe, 1.25 grams is a good approximation for the weight of a liter of air. You should be able to calculate the volume of helium at high and low altitudes by searching for the pressures and temperatures at those locations. Some of the helium formed escapes into the atmosphere, which contains about 5 parts per million by volume. 2023 BrainRouter LTD. All rights reserved. In this case, since the volume and molar quantity of the gas are changing, you need to solve the following equation: So, for this particular problem: 0.8323 L = 4.266 L. n 1 20.4 mol, or n 1 = (20.4) (0.8323) 4.266, or n 1 = 3.98 mol of helium initially. From these we can calculate the; lift, free-lift, ascent-rate and the burst altitude. From the moment a white orb was spotted floating 60,000 feet over Montana, people on Twitter and cable news demanded the Biden administration shoot it down. The following diagram shows the different lifting capacities of different volumes of helium: A 100-foot-diameter balloon can lift 33,000 pounds! And if we know this then we can calculate the density of the air at a particular altitude using the ideal gas equation, if we know the pressure and temperature at that altitude. Plugging in values for r and , we get V = 9.813.97 cm. Be sure that math assignments completed by our experts will be error-free and done according to your instructions specified in the submitted order form. # per Avg. Q: How many cubic meters of helium are required to lift a light balloon with a 370-kg payload to a. @EIMA I've added full equation details and some example data for you to take a look at. As of 2010, it took 300,000 cubic feet of helium to float the 15 character balloons in that year's Macy's Thanksgiving Day Parade, the equivalent volume of 2.2 million gallons of milk. How can I explain to my manager that a project he wishes to undertake cannot be performed by the team? What am I doing wrong here in the PlotLegends specification? The ideal gas law, PV = nRT, gives the relationship among pressure, volume, temperature and number of moles (n) for a gas. The balloon rises because of buoyancy. It may not display this or other websites correctly. 1 April 2000. No packages or subscriptions, pay only for the time you need. Assume the density of air is 1.28 kg/m3 and the density of helium in the balloon is 0.18 kg/m3. If you try a $pV=nRT$ calculation on these data, you see that the gas is already at around 10 times its initial volume with $\pu{40 mmHg}$ pressure and a $\pu{213 K}$ temperature, and that at the $\pu{50 km}$ point the volume is increased 700 times! 0.0001785 gram [g] of Helium fits into 1 cubic centimeter. Your local, ARA-affiliated rental store professionals also can assist you in renting the proper helium tank. At an altitude of $30$km, the temperature is $-46.6$C $\approx 226.9$K, the pressure is $1.20$kPa, and the density is $0.0184\text{kg}\text{m}^{-3}$. Helium weighs 0.1785 grams per liter. . Use MathJax to format equations. A helium balloon ride lifts up passengers in a basket. Thanks for contributing an answer to Chemistry Stack Exchange! 12 oz. To determine how much helium gas we need, we need to consider the necessary buoyancy required. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. The volume of a sphere is 4/3 * pi * r. One cubic foot of helium will lift about 28.2 grams, so multiply the volume of the balloon by 28.2. (1) The pressure of helium in each balloon is 1.1 10 5 Pa. This is only slightly larger than the surrounding air (atmospheric) pressure due to any surface tension in the balloon, so we can take the two to be roughly equal. Expert Answer. 2023 BrainRouter LTD. All rights reserved. I think they're mainly used for research and etc. How do you get out of a corner when plotting yourself into a corner, Is there a solutiuon to add special characters from software and how to do it, Styling contours by colour and by line thickness in QGIS. 50.L This is a problem involving the temperature-volume relationship of gases, which is represented by Charles's law: (V_1)/(T_1) = (V_2)/(T_2) Remember that T is the absolute temperature, so you must convert the temperature from Celcius to Kelvin: 25 ^o C + 273 = 298K 55 ^o C + 273 = 328 K Now, rearrange the equation to solve for V_2 (the new volume): V_2 = (V_1)(T_2)/(T_1) and plug in the . Helium balloons float because helium is less dense than air. The cart accelerates at4.15m/s^2. How can I determine whether balloons inside a balloon are filled with the same gas? Consider a helium balloon that is filled at sea level. How long will it take Helium weighs 0.0001785 gram per cubic centimeter or 0.1785 kilogram per cubic meter, i.e. In air, helium has a density of 0.2 kilograms/cubic meter . However, it is highly flammable, so the slightest spark can cause a huge explosion. where $R$ is the gas constant $= 8.314\text{J}\text{mol}^{-1}\text{K}^{-1}$. If you are measuring your balloon in feet, that gives you the volume of the balloon in cubic feet. &= \frac{PM_a}{RT} \implies M &= V\rho Thanks for contributing an answer to Physics Stack Exchange! Q: Calculate the volume (in m^3) of helium needed in a hot air balloon to lift at least 100 kg of load.. "How Helium Balloons Work" You can find this image quite interesting: You are exactly correct that it is a matter of atmospheric pressure decreasing at a rate great enough to overcome the contraction due to decrease in temperature. The input parameters are; temperature, balloon mass, payload mass, initial diameter and max diameter. The density of hydrogen gas at 0C and IUPAC standard pressure (100 kPa) is 9.00 g/m3. A weather balloon contains 8.80 moles of helium at a pressure of 0.992 atm and a temperature of 250C at ground level. If The speed of the cart, 1. As important. It turns out that helium is a lot lighter than air. There are three certainties in this world: Death, Taxes and Homework Assignments. To learn more, see our tips on writing great answers. The air in the tube is initiall, The cylinder of a pump has a volume of 25.0 cm3. In this edition of HowStuffWorks, you'll find out all about helium! Volume of balloon = 1200 m 3. mol to c O2Smol 1.010 0.20 g b. It was, and is still being, formed from alpha-particle decay of radioactive elements in the Earth. If the volume of the balloon stayed the same, this would require that the atmosphere has the same density at all altitudes. Adding helium to a balloon increased its volume from 832.3 mL to 4.266 L. If the final number of moles of helium in the balloon is 20.4 mol, what was the initial number of moles of helium in the balloon? of balloons and multiply by the weight per size. A great question!! You are using an out of date browser. The ideal gas law describes how the volume of a gas varies with amount, in mol, of gas particles, pressure, and temperature. a. Helium balloons are Mylar and not rubber because there is less space between the molecules in Mylar, so the balloon stays inflated longer. According to this source, the temperature at sea level is $15.0$C $ \approx 288.2$K, the pressure is $101$kPa, and the density is $1.23\text{kg}\text{m}^{-3}$.