False, pushing a sofa on a hardwood floor would be easier than on carpet.
 
        
             
        
        
        
Answer:
sorry i'm not a scientist but i think it's C
Explanation:
sorry again if i get it wrong for u :(
 
        
             
        
        
        
Answer:
grams H₂O produced = 8.7 grams
Explanation:
Given 2C₂H₆(g) + 7O₂(g) => 4CO₂(g) + 6H₂O(l)
                7g           18g                             ?g
Plan => Convert gms to moles => determine Limiting reactant => solve for moles water => convert moles water to grams water
Moles Reactants
moles C₂H₆ = 7g/30g/mol = 0.233mol
moles O₂ = 18g/32g/mol = 0.563mol 
Limiting Reactant => (Test for Limiting Reactant)  Divide mole value by respective coefficient of balanced equation; the smaller number is the limiting reactant. 
moles C₂H₆/2 = 0.233/2 = 0.12
moles O₂/7 = 0.08
<u><em>Limiting Reactant is O₂</em></u>
Moles and Grams of H₂O:
Use Limiting Reactant moles (not division value) to calculate moles of H₂O.
moles H₂O = 6/7(moles O₂) = 6/7(0.562) moles H₂O = 0.482 mole H₂O yield
grams H₂O = (0.482mol)(18g·mol⁻¹) = 8.7 grams H₂O
 
        
             
        
        
        
Based on the compounds given, I can say that the substance that is considered essential in the plastic making is NITRIC ACID. This substance is also known as aqua fortis and spirit of niter wherein this decomposes into oxides of nitrogen and water. The answer would be the last option. Hope this helps.
        
                    
             
        
        
        
1. Change in color
2. Formation of bubbles 
3. Formation of a precipitate
4. Begins to make an odor