Propane torch is lit inside a hot air balloon during pre-flight preparation because the heat from the touch is needed to heat the cold air inside the balloon, so that the air will expand and become less dense and rise, thus providing a lift for the balloon. This is line with charle's law, which states that, the volume of a fixed mass of ideal gas is directly proportional to the absolute temperature. This law implies that, as the temperature of the air inside the balloon increase, the volume of the balloon also increases.
Answer:
Oxygen
Explanation:
If two balloons are filled with hydrogen gas and helium gas respectively, then we want to identify what gas is in each balloon, we have to do so by exposing the both balloons to flame in an oxygen atmosphere.
Hydrogen combines with oxygen in the presence of a flame with quite a loud sound and the flame is sustained but when a flame is brought near helium gas in a balloon, the gas will only make a little sound when exposed to the flame and extinguish the flame.
The reason for the explosion of the gas in the hydrogen balloon is that combustion of hydrogen gas is exothermic. The heating up of surrounding air molecules leads to a sudden explosion.
However, the helium balloon makes a little sound when the balloon is ruptured releasing helium gas which extinguishes the flame.
Answer:
The half-life of Material 1 and Material 2 are equal.
step by step explanation;
Material 1 disintegrates to half its mass three times in 21.6 s, to go from 100g
to 12.5g. That is,
100g - 50g - 25g - 12.5g
Material 2 disintegrates to half its mass three times in 21.6 s, to go from 200g to 25g. That is,
200g - 50g - 25g - 12.5g.
This means that regardless of their initial masses involved, material 1 and material 2 have equal half-life.
Their half-life is 21.6 ÷ 3 = 7.2 sec
