Answer
For this we use ideal gas equation which is:
P1V1 = P2V2
P1 = 1.10 atm
V1 = 326 ml
P2 = 1.90
V2 = ?
By rearranging the ideal gas equation:
V2 = P1V1 ÷ P2
V2 = 1.10 × 326 ÷1.90
V2 = 358.6 ÷ 1.90
V2 = 188.7 ml
Molarity
Molarity is a unit used to express the concentration of a substance, and it is defined as the number of moles of solute per decimeter cubed (liter) of solvent.
The wave-mechanical model of the atom is required to explain the spectra of elements with multi electron atoms.
<u>Explanation:</u>
Wave mechanical theory say that every electron surrounding a nucleus occupies a certain orbit and moves in a certain direction, but the orbit is like a wave of energy or cloud but not a ring. It was proposed in the 1920s, when scientists Erwin Schrodinger and Louis Victor de Broglie concluded that the Bohr’s model is not suitable for electron location determination.
Based on many assumptions, scientists began to guess as accurately as possible about the behaviour of electrons at different energy levels around the nucleus. Because all electrons are negatively charged, they tend to push their elbows when they are too close together, moving away and changing direction. Each plane has one or more orbits that have more than one electrons that move around the nucleus in a specific patterns or shape.
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.
