ANSWER: The comma attempts to separate a compound subject.
EXPLANATION: The comma is used in a sentence where a pause is necessary. In this statement, the comma is separating a compound sentence which was unnecessary. The whole sentence is joined by the word 'and' and doesn't need any other word to give a pause in the sentence.
The comma is used incorrectly in the sentence above because it attempts to join two independent clauses without a coordinating conjunction.
The sentence "The graduate students filled out the necessary applications" and "submitted the required references" are both independent clauses, each having its own subject and verb. However, the comma is not sufficient to connect these two clauses properly. To correct this, a coordinating conjunction like "and" should be used after the first independent clause, or the comma could be replaced with a semicolon. The current use of the comma creates a comma splice error, which is a common grammatical mistake.
To know more about coordinating conjunction, here
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(3) the sample melts at 1768 K
(4) the sample can conduct electricity
Copper samples must have 29 protons, react with oxygen, melt at 1768 K, and conduct electricity.
In order for a sample of matter to be copper, it must meet certain criteria:
Therefore, if a sample of matter meets all of these criteria, it can be identified as copper.
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find the distance between
the following points:
a) AC0₂0) and B(5, 2)
concentration of calcium ions in this solution is
(1) 4.3 ppm (3) 17 ppm
(2) 8.5 ppm (4) 34 ppm
mass
neutrons
electrons
Answer:energy
Explanation:
Energy can be added to an atom to cause a non-valence electron in the atom to temporarily become a valence electron. The correct option is A.
Valence electrons are those electrons that are present in the outermost shell of the atom. These electrons are free to form bonds with another atoms.
Non-valence electrons are preset in the inner shell of the element. These shell are fulfilled with electrons, and these electrons does need to form bonds with other atoms to fulfill their orbit.
The electrons in the orbit have different energies present. The energy change when the electrons transfer from one shell to another shell. When energy is given to the electron, they move to the higher orbit or shell.
Thus, the correct option is A, energy.
To learn more about valence electrons, refer to the link:
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Answer: Therefore, the molar mass of the unknown substance is 68.4 g/mol.
Explanation: We can use the freezing point depression equation to solve for the molar mass of the unknown substance:
ΔT = Kf × m
where ΔT is the change in freezing point, Kf is the freezing point depression constant of the solvent (naphthalene), and m is the molality of the solution.
First, we need to calculate the molality of the solution:
molality = moles of solute / mass of solvent (in kg)
We don't know the number of moles of the unknown substance, but we can assume that the naphthalene does not contribute significantly to the total mass of the solution (since its mass is much smaller than the mass of the unknown substance). Therefore, we can use the entire mass of the solution (1000g + 12.3g = 1012.3g) as the mass of solvent.
mass of solute = 1000g
mass of solvent = 12.3g
mass of solution = 1012.3g
molality = (1000g / molar mass) / (12.3g / 1000g) = 81.3 / molar mass
Next, we need to calculate the change in freezing point:
ΔT = 1.2∘C
Finally, we can use the freezing point depression constant of naphthalene to solve for the molar mass of the unknown substance:
Kf for naphthalene = 6.8∘C/m
ΔT = Kf × m
1.2 = 6.8 × (81.3 / molar mass)
molar mass = 68.4 g/mol
Therefore, the molar mass of the unknown substance is 68.4 g/mol.