Balloons, helium

Matter can also be categorized into three distinct phases solid, liquid, and gas. An object that is solid has a definite shape and volume that cannot be changed easily. Trees, automobiles, ice, and coffee mugs are all in the solid phase. Matter that is liquid has a definite volume but changes shape quite easily. A liquid flows to take on the shape of its container. Gasoline, water, and cooking oil are examples of common liquids. Solids and liquids are termed condensed phases because of their well-defined volumes. A gas has neither specific shape nor constant volume. A gas expands or contracts as its container expands or contracts. Helium balloons are filled with helium gas, and the Earth s atmosphere is made up of gas that flows continually from place to place. Molecular pictures that illustrate the three phases of matter appear in Figure 1-12. 

Iave you ever tried to bounce a cold basketball or walked outside in the cold with a helium balloon Why is it never advisable to heat a sealed container As you might predict, these items act in an odd manner under different temperature conditions. Why does this happen In this lab, you will investigate the relationship between temperature and pressure, as proposed by Joseph Gay-Lussac. 

The ait inside the car has more inertia than the helium in the helium balloon. As the car starts forward, the greater inertia of the air causes it to pitch backwards, much like the girl s head. As this air holds to the back of the car, the lighter helium balloon moves forward. A similar effect can be seen when sliding a botde of water on its side across a table. As you accelerate die bottle forward, the water inside the bottle has an inertia that holds it back. Any bubble of air within the bottle thus runs forward in the direction that the bottle was pushed. 

An alpha particle consists of two protons and two neutrons. From that standpoint, an alpha particle is a helium nucleus. So, is that helium balloon full of alpha radiation Of course not. A helium atom also includes two electrons, so it is electrically neutral and chemically inert. An alpha particle has a net charge of +2, and it is has vastly more kinetic energy. 

Because no vacuum system can be truly leak-free, it is important to determine whether or not you have a leak of consequence. In other words, does any system leak actively affect your work For example, a common rubber balloon holds water better than it holds air, and it holds air better than it holds helium. If your needs are to contain water, a standard rubber balloon is sufficient. Similarly, if you want to contain helium for a limited time, again a rubber balloon is sufficient. However, if you want a helium balloon to stay up for several days, then a rubber balloon is insufficient and you must spend the money for a Mylar balloon, which can contain helium much better than a rubber balloon. 

As a class, hold a symposium about gas balloons. Research hot air balloons and helium balloons. Also research any other information about balloons, the history of ballons, and balloon travel that interests you. Prepare papers and posters to share your information. 

Helium balloons and hot air balloons also depend on the density of gases. These objects are filled with gases that are less dense than air. Therefore, they are able to float. 

A child releases a 2.5 L helium balloon that has an internal pressure of 3.4 atm. If a constant temperature is assumed, at what pressure will the balloon be 3.0 L ... 

If you release a helium balloon it soars upward and eventually pops. Explain. 

You have a helium balloon at 1.00 atm and 25°C. You want to make a hot-air balloon with the same volume and same lift as the helium balloon. Assume air is 79% nitrogen, 21% oxygen by volume. The lift of a balloon is given by the difference between the mass of air displaced by the balloon and the mass of gas inside the balloon. 

For instance, helium, neon, and argon each have filled shells, and this vertical column is commonly called the noble gases because of their dignified, inert, unreactive nature. Their lack of chemical reactivity is typified by helium, which is so unreactive that we use helium balloons for decorations at parties. Hydrogen, on the other hand, is very reactive. Hydrogen balloons at a party might result in entertainment more explosive than we would care for. 

It seems impossible that a light fabric bag can lift such a weight. It does so because the air inside the fabric bag or balloon is hotter than the outside air iuid the density of the heated air is much lower. Children s helium balloons float attached to their strings because the density of helium at room temperature and pressure is less than that of air. Release them from their strings and they will float off high into the sky - causing great distress to the children ... 

A helium balloon has a volume of 5 dm. How many moles of helium are in the balloon ... 

Density is the amount of mass for a certain volume. A block of iron is heavier than a block of wood that has the same size or volume. Iron is more dense than wood. Gases are not as dense as solids and liquids. Different gases have different densities. Hydrogen and helium are not as dense as oxygen and nitrogen. This is why a helium balloon floats up into the air. 

The density profiles for several clusters at different bubble radii are portrayed in Fig. 14. These density profiles reflect on the formation of a helium balloon with a finite thickness (8R in the cluster. The profile thicknesses for the... 

Figure 14. The density profiles at different bubble radii for ( He)jy clusters with iV= 1.88x10 reflecting on the formation of a helium balloon with a finite thickness (AR = R — Rb) in the cluster. The profile thicknesses for the bubble and for the cluster surface obtained from this simple model are t, t2 = 6-lOA (see text). The exterior surface profile of the cluster was characterized by the 90-10% fall-off width W2, while the interior bubble profile was characterized by a 10-90% rise width wj. For N = 1.88 x 10 clusters wi = 6.2 A for Rt = 0 (no bubble), W2 = 7.8 A and wi = 6.2 A for Rj = 10.3 A, while W2 = 6.8 A and Wi = 12.3 A for Rb = 19.2 A. These results demonstrate that the cluster surface profile width n>2 remains nearly independent of the bubble size, while Wi increases with increasing the bubble radius.

We now introduce an excess electron into the bubble, which is located in the center of the helium cluster at a fixed nuclear configuration of the helium balloon. The electronic energy of the excess electron will be calculated within the Born-Oppenheimer separability approximation. We modified the nonlocal effective potential developed by us for surface excess electron states on helium clusters [178-180] for the case of an excess electron in a bubble of radius Rb... 

Example A helium balloon has a volume of 45.2 L at a pressure of 745 mmHg. What would its volume be after floating high in the air where the pressure is 640 mmHg No helium leaks from the balloon, and the temperature does not change. 

Answer The volume of the helium balloon will expand from 45.2 L to 52.6 L as the pressure exerted on the gas falls from 745 to 640 mmHg. 

You are holding two helium balloons, a large balloon and a small balloon. How do the pressures of helium compare ... 

Example 2.12, A helium balloon is at the same pressure and temperature as the surrounding air (1 atm, 20 C) and has a diameter of 3 m. The weight of the plastic skin of the balloon is negligible. How much paylpad can the balloon lift ... 

A helium balloon has a flexible skin of negligible weight and infinite capacity for expansion, so that the helium is always at the same pressure as the surrounding air. If the mass of helium in the balloon is lOlbm, hO W much payload can it lift under the following conditions (a) 1 atm and 70°F, (b) 0.01 atm and 0°F, and (c) 0.001 atm and -100°F Assume that helium behavps as a perfect gas with M = 4 g/mol and that its temperature is always the same as the temperature of the surrounding air. 

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