Answer:
The percent by mass of water in this crystal is:
Explanation:
This exercise can be easily solved using a simple rule of three where the initial weight of the hydrated crystal (6,235 g) is taken into account as 100% of the mass, and the percentage to which the mass of 4.90 g corresponds (after getting warm). First, the values and unknown variable are established:
- 6,235 g = 100%
- 4.90 g = X
And the value of the variable X is found:
- X = (4.90 g * 100%) / 6,235 g
- X = approximately 78.6%.
The calculated value is not yet the percentage of the water, since the water after heating the glass has evaporated, therefore, the remaining percentage must be taken, which can be calculated by subtraction:
- Water percentage = Total percentage - Percentage after heating.
- <u>Water percentage = 100% - 78.6% = 21.4%</u>
When the concentration is expressed in 14 percent volume, it means that there are 14 units of volume of solute per 100 units of volume of solution. Since there is a total volume of solution of 0.750 L, the solution is as follows:
0.750 L * 1,000 mL/1 L * 100 mL/ 14 mL = 5,357.14 mL pure alcohol
For the purpose we will use solution dilution equation:
c1xV1=c2xV2
Where, c1 - concentration of stock solution; V1 - a volume of stock solution needed to make the new solution; c2 - final concentration of new solution; V2 - final volume of new solution.
c1 = 5.00 M
c2 = 0.45 M
V1 = ?
V2 = 108 L
When we plug values into the equation, we get following:
5 x V1 = 0.45 x 108
<span>V1 = </span>9.72 L
Answer:
The state of matter is liquid
Explanation:
Since the frozen point in celcius is 32 then at 30 its still liquid
Explanation:
Electron configuration can be carried out in two steps which can be:
- Sublevel notation
- Shell notations.
In the sublevel notation, the sequence of filling electrons into the orbitals of the sublevels are guided by some principles:
- the maximum number of electrons in the orbital of sublevels are two for s-sublevel, six for p-sublevel, ten for d-sublevel and fourteen for f-sublevel. This indicates that the maximum number of electrons in an orbital is two.
- Aufbau's prinicple states that sublevel with lower energies are filled up before those with higher energies.
- Pauli exclusion principle states that no two electrons in an atom can have the same set of the four quantum numbers.
- Hund's rule states that electrons go into degenerate orbitals singly first before pairing occurs.
Using the shell notation, numbers are used to denote the sum of electrons in all orbitals each energy level.
For an atom of Be:
Sublevel notation for the 4 electrons 1s²2s²
Shell notation 2,2
Other representation is using the electron dot structure.
Learn more
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