Your answer to #2 is <span>There are several differences between a </span>physical<span> and chemical </span>change in matter<span> or substances. A </span>physical change<span> in a substance doesn't </span>change<span> what the substance is. In a chemical </span>change<span> where there is a chemical reaction, a new substance is formed and energy is either given off or absorbed. </span>
Answer:
Second option. 3
Explanation:
In order to balance a equation you need to have the same amount of atoms/moles in both sides.
Na₃PO₄ + _ HCl → 3NaCl + H₃PO₄
In reactant side we have 3 Na and we have the same amount in product side.
We also have 1 P and 4 O in both sides of the equation.
As we have 3 moles of NaCl in product side, this means we have:
NaCl → Na⁺ + Cl⁻
3 moles of Na⁺ and 3 moles of Cl⁻. In conclussion we need 3 moles of Cl⁻ in reactant side.Then, the stoichiometry of HCl must be, 3.
3 moles of HCl means that we have 3 moles of protons (H⁺).
HCl → H⁺ + Cl⁻
If you see the phosphoric acid, we also have 3 moles of protons.
H₃PO₄ → 3H⁺ + PO₄³⁻
Complete balanced equation is:
Na₃PO₄ + 3HCl → 3NaCl + H₃PO₄
The given reaction is C₅H₉O + O₂ → CO₂ + H₂O
On balancing the equation we get:
20 C₅H₉O + 90 O₂ → 100 CO₂ + 9 H₂O
This is a single replacement type of reaction. A single replacement reaction, also called a single-displacement reaction, refers to a kind of chemical reaction where an element reacts with a compound and occupies the place of another element in that compound.
Calculate the number of mole of 5O2:
1.2 x 5/4=1.5 mol