Answer:
We need 226 grams of FeS
Explanation:
Step 1: Data given
Mass of FeCl2 = 326 grams 
Molar mass FeCl2 = 126.75 g/mol
Step 2: The balanced equation
FeS + 2 HCl → H2S + FeCl2
Step 3: Calculate moles FeCl2 
Moles FeCl2 = 326 grams / 126.75 grams
Moles FeCl2 = 2.57 moles
Step 4: Calculate moles FeS needed
For 1 mol H2S and 1 mol FeCl2 produced, we need 1 mol FeS and 2 moles HCl 
For 2.57 moles FeCl2 we need 2.57 moles FeS
Step 5: Calculate mass FeS
Mass FeS = 2.57 moles * 87.92 g/mol
Mass FeS = 226 grams FeS
We need 226 grams of FeS
 
        
             
        
        
        
They have a full valence shell (8 electrons in the outer shell) so they are the most stable elements on the periodic table. Therefore, they do not need to react to other elements to gain or lose elections to become stable. 
        
             
        
        
        
Answer:
B
Explanation:
B It’s a physical change because the water and the salt kept their original properties.
 
        
                    
             
        
        
        
A decomposition reaction should look like
A ------> B +C+...
It has to have only one reactant and several products.
 2 NO2 ⟶ 2 O2 + N2 
 
        
                    
             
        
        
        
initial volume of the argon sample = 5.93L according to Boyle's law
What is Boyle's law ?
Boyle's law, also known as Mariotte's law, is a relationship describing how a gas will compress and expand at a constant temperature. The pressure (p) of a given quantity of gas changes inversely with its volume (v) at constant temperature, according to this empirical connection, which was established by the physicist Robert Boyle in 1662. In equation form, this means that pv = k, a constant.
According to Boyle's law
P1/V1 = P2/V2
P1 = initial pressure
P2 = final pressure
V1 =initial volume
V2= final volume
V1 = P1*V2/P2
V1 = 2.32*18.3/7.16 = 5.93L
 initial volume of the argon sample = 5.93L according to Boyle's law
To know about Boyle's law from the link
brainly.com/question/26040104
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