Answer:
Since moles are just "some number of particles", and since one O2 molecule contains enough oxygen for two H2O molecules, you need 2.5 moles of O2 for 5 moles of H2O.
Given :
Number of He atoms, 
atoms.
To Find :
How many grams are their in given number of He atoms.
Solution :
We know, molecular mass of He is 4 g. It means that their are 
atoms in 4 g of He.
Let, number of gram He in 
atoms is x , so :
Therefore, grams of He atoms is 22.58 g .
Answer:
It is a model of the atom that has electrons surrounding the nucleus
Step by step explanation:
It is due to a lack of providable energy to the next trophic level of the energy pyramid. Primary consumers only obtain around 10% of energy that producers have, and the energy depletes as you move further and further up the food chain, until you reach the tertiary consumers which have the least amount of energy at their disposal, meaning there are less of them than other organisms further down the energy pyramid.
Hope this helped!
