Answer:
- <em><u>A physical change has occurred, with no energy change.</u></em>
Explanation:
When a pencil lead is broken there is not change of any chemical properties, therefore it is not a chemical change, but just a physical change. In this case the change is just the number of pieces and dimensions.
Chemical changes always involve the formation of new different substances; the bonds between the atoms of the starting substances (reactants) breake and new bonds are formed leading to new substances (products) with different chemical composition (arrange of atoms). Chemical changes occur through chemical reactions.
Hence, if there is not change on the chemical composition, you think on physical changes. Physical changes include change in shape, size, state of matter (e.g. solid, liquid, gas). In the case of a pencil lead breaking, it is a change in shape and size.
Also, since energy has not been absorbed or released during the change, the energy of the pencil lead before having been broken is equal to the sum of the energies of the pieces of pencil lead obtained. So, this is a physical change with no energy changes.
Some examples of physical changes that include change in energy are the change of state (e.g. solid to liquid or liquid to gas) and the dissolution of a compound.
The answer of this question is Oxygen
Answer:
3
Explanation:
Primary waves are radiated along a single direction, but secondary waves are radiated along all directions. That is why the P waves can take place in almost all mediums such as solid, liquid and air, unlike the S waves that are transverse and only travel through solid mediums
<u>Answer:</u> The amount of oxygen gas consumed is 0.525 moles
<u>Explanation:</u>
We are given:
Moles of propane burned = 0.150 moles
The chemical equation for the combustion of propane follows:
![C_3H_8+5O_2\rightarrow 3CO_2+4H_2O](https://tex.z-dn.net/?f=C_3H_8%2B5O_2%5Crightarrow%203CO_2%2B4H_2O)
By Stoichiometry of the reaction:
1 mole of propane reacts with 5 moles of oxygen gas
So, 0.150 moles of propane will react with =
of oxygen gas
Hence, the amount of oxygen gas consumed is 0.525 moles