Answer:
number of moles = 0.21120811
Explanation:
To find the number of moles, given the mass of the solute, we use the formula:




Label the variables with the numbers in the problem:



The first thing we have to do is find the molar mass of sodium sulfate, in order for us to use the formula for finding the number of moles:
Formula for finding the molar mass of sodium sulfate:

For the variables and what they mean are below for finding the molar mass of sodium sulfate:





Plug the numbers into the formula, to find the molar mass of sodium sulfate:











Now that we have found the molar mass, we can calculate the number of moles in the solution of sodium sulfate with the formula:








0.21120811 rounded gives you 0.2112 
or if you did the problem without decimals
30 grams of sodium sulfate divided by its molecular weight – which we found to be 142 – gives us a value of 0.2113 moles.
 
        
             
        
        
        
<span>The answer is D)<em> </em>are compounds that have the same number and types of atoms but are arranged differently.
Source: <em>just took the test :)</em></span>
        
             
        
        
        
Answer:
A rock is an inconsistent mixture of minerals, while mineral is "pure" and made  up of a precise combination of chemicals.
Explanation:
 
        
             
        
        
        
Answer:
《HOPE IT WILL HELP YOU 》 
Explanation:
2 Atom of Hydrogen are present in 2 (NaHCO3)
 
        
             
        
        
        
The balanced chemical reaction is:
N2 + 3H2 = 2NH3 
 
We are given the amount of ammonia formed
from the reaction. This is where we start our calculations. 
 
0.575 g NH3 (1 mol NH3 / 17.03 g NH3) (3 mol
H2 / 2 mol NH3) ( 2.02 g H2 / 1 mol H2) = 0.10 g H2