Question 17
The subscript 2 is the atomic number for helium and subscript 4 is the mass number for Helium
<u><em>explanation</em></u>
when writing down an isotope of an element the mass number of that isotope is written in upper side of the chemical symbol, while atomic number is written on the lower side.
Since 4 is on upper side it is the mass number of He, while 2 is the atomic number since it is on lower side.
Question 18
The type of radiation emitted when polonium -212 form lead 208 is an alpha particle
<u><em>explanation</em></u>
Alpha decay is a decay in which an atomic nuclei emit an alpha particles and be transformed into different atomic nuclei with a mass number that is reduced by 4
polonium 212 is reduced by 4 to form lead 208 therefore it undergo alpha particle decay.
Answer:
reactivity
Explanation:
a chemical reacting to another chemical is considered a Chemical property because chemicals react with other chemicals differently
Plants extract the carbon dioxide from the air and use it in photosynthesis process to feed themselves.
Hello, I Am BrotherEye
Answer:
As the atmospheric pressure decreases with increase in altitude, when a sealed bag of chips is taken to higher altitude then the pressure of the gases inside the bag become greater than the outer atmospheric pressure and apply pressure on the side covering of the chips bag due to which the chips bag expand.
Explanation:
Atmospheric pressure decreases with increasing altitude. Let's assume you tie up a bag at sea level altitude (with little air inside). That air inside the bag is at 1atm as long as you're at sea level.
Now you start going up, your altitude increases and atmospheric pressure decreases (remember what I said in the beginning about atmospheric pressure decreasing with increasing altitude?).
Let's say you reach an altitude where the atmospheric pressure is 0.5atm, the force acting inside the bag which is pushing it outward is now greater than the force acting on it which is pushing it inward (1atm>0.5atm). As a result, the air inside the bag will push the sides of the bag outward, thus inflating it to a point where the pressure inside the bag becomes 0.5atm or the bag stops stretching.
For the same reason, if you bring the same bag down and take it too deep into the earth (at an altitude lower than sea level) or if you inflate the bag at a very high altitude and bring it down to sea level, it will deflate.
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BrotherEye
Answer:
Le Chatelier's principle, also called Chatelier's principle or "The Equilibrium Law", is a principle of chemistry used to predict the effect of a change in conditions on chemical equilibria.
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