Answer:
Hydrogen
Explanation:
Balloons are filled with light gases in order to make them float. Helium and Hydrogen are both light gases.
Helium is quite a lot lighter than air: it's about an eighth of the density of air. Hydrogen is about a sixteenth the density of air, so it'll float in air and will in fact float upwards.
Hydrogen however is twice as heavy as helium, but that doesn't mean the amount of lift off of the balloon is twice as much. The amount of lift is determined by the difference in density with respect to air.
Hydrogen is calculated to be less dense than helium, that explains why hydrogen filled balloons would go up higher.
Helium filled balloons are used because of the safety implications. The problem is that hydrogen is explosive may have some health and safety implications! Helium is much more safe to use.
Spinning top, moving car, and rolling ball have kinetic energy I believe
The mass of pentane the student should weigh out is
The density of pentane is 0.626 gcm-3
To calculate the mass of pentane following expression is used,
(Density is defined as the mass divide by volume)
Density = mass / volume
mass of pentane = Density of pentane * Volume of pentane
mass of pentane = 0.626 gcm-3 * 45.0 mL
= 28.17 g
Here the unit of mass of pentane is g,
However the unit of density is gcm-3 and unit of volume is mL i.e. cm3
Hence, Mass = gcm-3 * cm3
Mass = g
The mass of pentane the student should weigh out is 28.17g
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