Pleaseeee helpp its a HW question
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The valence of aluminum is +3, and the valence of chlorine is –1. The formula for aluminum chloride iscorrectly written asA. ClAl3.B. Cl3Al.C. AlCl3.D. Al3Cl.
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Answer: Na⁺, SO₄ ²⁻.
Justification:
This is just a part of a bigger question.
But the instructions are complete to construct the ions.
The first ion requested is the sodium ion.
The symbol of sodium is Na.
When an electron is removed from the neutral atom, the atom wil result with an excess of protons, which translates onto an excess of positive charge.
Then, to show the new particle you must add a positve sign (+) in the form of superscript.
That is why you write Na⁺. By the way, a positive ion is named cation.
Regarding sulfate ion, it comes from the sulfuric acid, when you remove the two hydrogen atoms, each with a positive charge, then the sulfate ion will stand with a negative charge of 2.
The charge is told to belong to the entire ion, not a particular atom, soy you wirte it with the 2- symbol as a superscript for the entire species:
SO₄ ²⁻. A negative ions is called anion.
The answer, then, is: Na⁺, SO₄ ²⁻.
Writing the ion: Na⁺,SO₄²⁻
Further explanation
Ionic compounds consisting of cations (ions +) and anions (ions -)
The naming is preceded by the cation then the anion with the -ide suffix added
Generally for this ion compound consists of metal elements as cations and non-metals as anions
Metal: cation, positively charged.
Nonmetal: negative anion.
The anion cation's charge is crossed
Example:
Fe₂S₃
Fe charge = 3+
S charge = 2-
The writing of the ionic charge is placed as a superscript behind the molecule/ atom, and the number is written before the positive or negative sign. For a single charge, there is no need to write the number
Example
Cl⁻ (single charge)
Mg²⁺ not Mg⁺²
For the element Na symbol which is group 1A and releases one electron, the symbol writing would be: Na⁺(single charge)
For polyatomic ions, the superscript charge is written after the subscript on the polyatomic element, so it becomes SO₄²⁻
These two ions when combined and bind to Na₂SO₄ (The anion cation's charge is crossed)
if written separately as Na⁺, SO₄²⁻
Learn more
the chemical formula for each ionic compound.
two functional groups that contain ionic charges
Binary ionic compounds
Keywords: chemical compound, the naming of chemical compounds
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According to the concept of Avogadro's number, there are 1.505×10²³ molecules in 0.25 mole of O₂.
What is Avogadro's number?
Avogadro's number is defined as a proportionality factor which relates number of constituent particles with the amount of substance which is present in the sample.
It has a SI unit of reciprocal mole whose numeric value is expressed in reciprocal mole which is a dimensionless number and is called as Avogadro's constant.It relates the volume of a substance with it's average volume occupied by one of it's particles .
According to the definitions, Avogadro's number depend on determined value of mass of one atom of those elements.It bridges the gap between macroscopic and microscopic world by relating amount of substance with number of particles.
Number of atoms can be calculated using Avogadro's number as follows: mass/molar mass×Avogadro's number
Number of molecules is obtained by multiplying number of moles and Avogadro's number , that is 0.25×6.023×10²³=1.505×10²³ molecules.
Thus, there are 1.505×10²³ molecules in in 0.25 mole of O₂.
Learn more about Avogadro's number,here:
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0,25 mole O2 ---------------- x molecules
1 . x = 0,25 . 6,02.10²³
x = 1,50.10²³ molecules
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70 Determine the number of moles of copper in the bracelet. [1]
71 Show a numerical setup for calculating the amount of heat released by the bracelet as it cooled on the desk. [1]
72 Explain, in terms of chemical activity, why copper is a better choice than iron to make the bracelet. [1]
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69. The student's skin was obviously warmer than the initial temperature of the bracelet. According to the second law of thermodynamics, heat transfers from a higher temperature to a lower temperature. Hence, heat transfers from the student's skin to the bracelet warming up the bracelet.
70. To determine number of moles of copper:
Given mass=30.1 grams
Molar mass= 63.55 g/mol
Thus, the number of moles of copper is 0.4736.
71. Calculating the amount of heat released:
ΔH( heat released) = m Cp(ΔT)
= 30.1g(0.385 J/g. K)(33-19)K
ΔH= 162.23J
Thus, the amount of heat released is 162.23 J.
72. Copper is chemically less active than iron.
Copperdoes notdisplace iron from its solution since it is less reactive than iron. A more reactive metal displaces a less reactive metal from its solution.
Learn more:
70. moles of copper=mass of copper/molar mass of copper
=30.1g/(63.55g/mol)= 0.4736 moles Cu
71. Delta H( heat released) = mCp(deltaT) = 30.1g(0.385 J/gK)(33-19)K = 162.23J
72. Copper is chemically less active than iron.
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Answer:
The answer is 8.00 moles
Explanation:
To find the number of moles in a substance given it's number of entities we use the formula
where n is the number of moles
N is the number of entities
L is the Avogadro's constant which is
6.02 × 10²³ entities
From the question we have
We have the final answer as
8.00 moles
Hope this helps you
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Answer:
The chloride ion has a -1 charge and it tends to form such an ion because it wants the octet rule to be complete, and since it has 7 it needs one more for 8 electrons.
Hope this helps!
Explanation: