Answer:
The empirical formula is =  
Explanation:
Given that:- Mass of nickel = 2.241 g
Mass of the oxide formed = 2.852 g
Mass of the oxygen reacted = Mass of the oxide formed - Mass of nickel  = 2.852 g - 2.241 g = 0.611 g
Molar mass of nickel  = 58.6934 g/mol
Moles of nickel =  = 0.03818 mol
 = 0.03818 mol
Molar mass of oxygen  = 15.999 g/mol
Moles of nickel =  = 0.03818 mol
 = 0.03818 mol
Taking the simplest ratio for Ni and O as:
0.03818 : 0.03818 = 1 : 1
<u>The empirical formula is =  </u>
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Matter is anything that has mass and volume
        
                    
             
        
        
        
Answer:

Explanation:
<u>Convert Atoms to Moles</u>
The first step is to convert atoms to moles. 1 mole of every substance has the same number of particles: 6.022 ×10²³ or Avogadro's Number. The type of particle can be different, in this case it is atoms of silver. Let's create a ratio using this information. 

We are trying to find the mass of 8.23 ×10²³ silver atoms, so we multiply by that number. 

Flip the ratio so the atoms of silver cancel. The ratio is equivalent, but places the other value with units "atoms Ag" in the denominator. 


Condense into one fraction. 


<u>Convert Moles to Grams</u>
The next step is to convert the moles to grams. This uses the molar mass, which is equivalent to the atomic mass on the Periodic Table, but the units are grams per mole. 
Let's make another ratio using this information. 

Multiply by the number of moles we calculated. 

The moles of silver cancel out. 



<u>Round</u> 
The original measurement of atoms has 3 significant figures, so our answer must have the same. For the number we calculated, that is the ones place. 
The 4 in the tenths place tells us to leave the 7 in the ones place. 

8.23 ×10²³ silver atoms are equal to approximately <u>147 grams.</u>
 
        
             
        
        
        
694,563,239 rounded to the nearest thousand is 694,563.
 
It's because the first digit from the right is for ones, second for tens, third for hundreds and fourth for thousands and that's the one that we should take a closer look at. You can round it either to 3 or 4, depends on the digit of hundreds. In this case 3239 is clearly closer to 3000 than 4000, that's why we round it to 694,563, not 694,564.
        
                    
             
        
        
        
Answer:
1.2
Explanation:
Molarity = moles/volume
to find the moles, you must multiply both sides by volume
so, take 1.5 L * 0.80 M
this equals 1.2 :)