a. 2Na Al 03
Equation must have the same number of each element on both sides of the equation.
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 .
Scientific investigation: The process in which scientist solve the question by using different systematic approach. It can be initiated in different ways.
Experimental Scientific investigation: The investigation in which scientist answer the question on the basis of experimental results. Experimental investigation includes both dependent and independent variables, and only one variable is tested at a time is possible.
The best example of an experimental scientific investigation is: when we placed a whole apple and apple slice under sun, and noted down how many days it will take to rot in order to compare the break down of apple slice and whole apple.
Thus, option (B) is the correct answer.
CO is not an element because CO is a Compound. Elements contain One capital and one lowercase letter. While Compounds contain two or more capital letters.
Physical because it is still H2O
