The answer to your question is D. Sound waves travel faster in more dense material, and the more dense the material the louder the sound is.
Answer:
a) 129.14 g/mol
b) 8.87
Explanation:
Given that:
mass of the ionic compound [NaA] = 18.08 g
Volume of water = 116.0 mL = 0.116 L
Let the mole of the acid HCl = 0.140 M
Volume of the acid = 500.0 mL = 0.500 L
pH = 4.63
= 1.00 L
Equation for the reaction can be represented as:

From above; 1 mole of an ionic compound reacts with 1 mole of an acid to reach equivalence point = 0.140 M × 1.00 L
= 0.140 mol
Thus, 0.140 mol of HCl neutralize 0.140 mol of ionic compound at equilibrium
Thus, the molar mass of the sample = 
= 129.14 g/mol
b) since pH = pKa
Then pKa of HA = 4.63
Ka = ![10^{-4.63]](https://tex.z-dn.net/?f=10%5E%7B-4.63%5D)
= 
![[A^-]equ = \frac{0.140M*1.00L}{1.00L+0.116L}](https://tex.z-dn.net/?f=%5BA%5E-%5Dequ%20%3D%20%5Cfrac%7B0.140M%2A1.00L%7D%7B1.00L%2B0.116L%7D)

= 0.1255 M
of HA = 


+
+ 
Initial 0.1255 0 0
Change - x + x + x
Equilibrium 0.1255 - x x x
![K_b = \frac{[HA][OH^-]}{[A^-]}](https://tex.z-dn.net/?f=K_b%20%3D%20%5Cfrac%7B%5BHA%5D%5BOH%5E-%5D%7D%7B%5BA%5E-%5D%7D)
![4.35*10^{-10} = \frac{[x][x]}{[0.1255-x]}](https://tex.z-dn.net/?f=4.35%2A10%5E%7B-10%7D%20%3D%20%5Cfrac%7B%5Bx%5D%5Bx%5D%7D%7B%5B0.1255-x%5D%7D)
As
is very small, (o.1255 - x) = 0.1255

[OH⁻] = 
But pOH = - log [OH⁻]
= - log [
]
= 5.13
pH = 14.00 = 5.13
pH = 8.87
Answer:
1.14 moles of oxygen will react
Explanation:
The balanced equation of reaction between iron and oxygen is
4 Fe + 3 O₂ → 2 Fe₂O₃
By stoichiometry of the reaction (that is, the relationship between the amount of reagents and products in a chemical reaction), the following amounts of each compound participate in the reaction:
- Fe: 4 moles
- O₂: 3 moles
- Fe₂O₃: 2 moles
The molar mass of iron being Fe 55.85 g/mole, then the following amount of mass reacts by stoichiometry: 4 moles* 55.85 g/mole=223.4 g
You can apply the following rule of three: if by stoichiometry 223.4 grams of Fe react with 3 moles of O₂, 84.9 grams of Fe react with how many moles of O₂?

moles of O₂= 1.14 moles
<u><em>1.14 moles of oxygen will react</em></u>
<u><em></em></u>
The pressure of NO2 and N2O4 would be 1.756 atm and 0.1542 atm respectively.
<h3>Gas laws</h3>
According to Boyle's law, the pressure of a gas is inversely proportional to its volume at a constant temperature.
Mathematically: P1V1=P2V2
When the volume of a gas is halved at a constant temperature, the pressure is doubled. If it is the volume is doubled, the pressure would be halved.
In this case, the volume of the container is halved. Meaning that the pressure of each of the gas would be doubled by the time the equilibrium is reestablished.
Thus, NO2 would double from 0.878 atm to 1.756 atm while N2O4 will double from 0.0771 atm to 0.1542 atm
More on gas laws can be found here: brainly.com/question/1190311
Answer is: one electron in the first three orbitals, none in the fourth or fifth orbitals. All three electrons will have parallel spins (<span>unpaired </span><span>electrons).
This is </span><span>Hund's rule - orbitals of the same energy are each filled with one electron before filling any with a second, these first electrons have the same spin.</span> <span>
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