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 showing hydrogen peroxide decomposing into hydrogen and oxygen is:

Answer:
168.56 mL
Explanation:
density = mass/volume, use basic algebra skills to replace the volume and solve
I believe that the subject is supposed to be science
Answer:
Net ionic equation:
Ca⁺²(aq) + CO²⁻₃(aq) → CaCO₃(s)
Explanation:
Chemical equation:
K₂CO₃ + CaCl₂ → KCl + CaCO₃
Balance chemical equation:
K₂CO₃(aq) + CaCl₂(aq) → 2KCl(aq) + CaCO₃(s)
Ionic equation:
2K⁺(aq) + CO²⁻₃(aq) + Ca⁺²(aq) + 2Cl⁻(aq) → 2K⁺(aq) + 2Cl⁻(aq) + CaCO₃(s)
Net ionic equation:
CO²⁻₃(aq) + Ca⁺²(aq) → CaCO₃(s)
The K⁺(aq) and Cl⁻ (aq) are spectator ions that's why these are not written in net ionic equation. The CaCO₃ can not be splitted into ions because it is present in solid form.
Spectator ions:
These ions are same in both side of chemical reaction. These ions are cancel out. Their presence can not effect the equilibrium of reaction that's why these ions are omitted in net ionic equatio
n.