How does the law of conservation of mass apply to this reaction: C2H4 + O2 → H2O + CO2?
Answer: 
Explanation:
According to the law of conservation of mass, mass can neither be created nor be destroyed. Thus the mass of products has to be equal to the mass of reactants. The number of atoms of each element has to be same on reactant and product side. Thus chemical equations are balanced.
The balanced chemical equation for combustion of propane will be :

The color of a substance is correct, also if the substances starts to bubble describes a small portion of a chemical reaction.
The chemical reaction produces a new substance with new and different physical and chemical properties. Matter is never destroyed or created in chemical reactions. The particles of one substance are rearranged to form a new substance. .
Answer:
<h2>9.46 g/mL</h2>
Explanation:
The density of a substance can be found by using the formula

From the question
mass = 1892.6 g
volume = 200 mL
We have

We have the final answer as
<h3>9.46 g/mL</h3>
Hope this helps you