Answer:
[See Below]
Explanation:
✦ Physical Changes:
✧ Is when the form changes, but not the chemicals in that form.
✧ An example of this would be chopping wood. It's still wood but it's a different size now. It's easier to burn it since it's smaller.
✦ Chemical Changes:
✧ Is when the chemicals inside that form change to something else entirely
✧ An example would be an egg, when you cook the egg it can turn into being scrambled or fried. But you can't eat the raw egg until the chemicals change.
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Answer:
Pb₂O₄
Explanation:
The given species are:
Pb⁴⁺ O²⁻
Now, to solve this problem, we use the combining powers which corresponds to the number of electrons usually lost or gained or shared by atoms during the course of a chemical combination.
Pb⁴⁺ O²⁻
Combining power 4 2
Exchange of valencies 2 4
Now the molecular formula is Pb₂O₄
Answer:
It is a physical change because this change is reversible and no chemical reaction occurs.
Explanation:
Unburned hydrocarbon on reacting with oxygen undergoes combustion reaction. However, the activation energy of this reaction is significantly high. When a catalyst like Pd is added to the reaction system, it provides active sites for the reaction to occur. It acts are a heterogeneous catalyst. It is pertinent of note that catalyst is refereed as heterogeneous, when it exist in different phase as compared to reactant and products. In present case, reactants and products are in gas phase, while catalyst is in solid phase. Due to availability of larger surface area at active site of Pd, activation energy of reaction decreases and decrease in activation energy favors higher reaction rates.
Answer:
the 6 stands for the atomic number
the 12.01 stands for the atomic mass
