40.0 g ( 1 mole ) --------------- 6.02x10²³ molecules
      ? ? --------------------------- 2.90x10²² molecules
mass = 2.90x10²² * 40.0 /  6.02x10²³
mass = 1.16x10²⁴ / 6.02x10²³
mass = 1.9269 g
hope this helps!
        
             
        
        
        
Answer:
Percentage mass of copper in the sample = 32%
Explanation:
Equation of the reaction producing Cu(NO₃) is given below:
Cu(s)+ 4HNO₃(aq) ---> Cu(NO₃)(aq) + 2NO₂(g) + 2H₂O(l)
From the equation of reaction, 1 mole of Cu(NO₃) is produced from 1 mole of copper. Therefore, 0.010 moles of Cu(NO₃) will be produced from 0.010 mole of copper.
Molar mass of copper = 64 g/mol
mass of copper = number of moles * molar mass
mass of copper = 0.01 mol * 64 g/mol = 0.64 g
Percentage by mass of copper in the 2.00 g sample = (0.64/2.00) * 100%
Percentage mass of copper in the sample = 32%
 
        
             
        
        
        
I don't know if this was your answer choice but I actually got the answer to be toothpaste.
hydrated alumina, calcium carbonate, make up toothpaste
Again idk if this was an answer choice but I hope this helps, have a good day, sorry if not. c;