Answers
number of moles solute:
n = mass of solute / molar mass
n = 30 / 39.997
n = 0.00075 moles of NaOH
Volume in liters:
500 mL / 1000 => 0.5 L
Therefore :
M = moles of solute / volume ( L )
M = 0.00075 / 0.5
M = 0.0015 mol/L
Answer: 1.5 M
Explanation:
Related Questions
assume in a different experiment, you prepare a mixture containing 10.0 M FeSCN2+, 1.0 M H+, 0.1 MFe3+ and 0.1 M HSCN. Is the initial mixture at equilibrium? If not, in what direction must the reactionproceed to reach equilibrium? (Hint: You will need to use the value of Kc you determined in the lab
What was the molecular geometry for SC16?
If you wanted to change the polarity of hydrogen bromide (HBr) by substituting the bromine with a different atom. Which atom would increase the polarity of the molecule?
Draw the Lewis structure for the polyatomic hydronium H3O cation. Be sure to include all resonance structures that
Answers
Answer:
pH = 11.7
Explanation:
pOH= -log [OH]=-log[0.05]
=2.3
pOH+pH= 14
pH= 14-2.3= 11.7
Answers
Answer:
The free energy = -20.46 KJ
Explanation:
given Data:
Pb²⁺ = 0.750 M
Br⁻ = 0.232 M
R = 8.314 Jk⁻¹mol⁻¹
T = 298K
The Gibb's free energy is calculated using the formula;
ΔG = ΔG° + RTlnQ -------------------------1
Where;
ΔG° = standard Gibb's freeenergy
R = Gas constant
Q = reaction quotient
T = temperature
The chemical reaction is given as;
Pb²⁺(aq) + 2Br⁻(aq) ⇄PbBr₂(s)
The ΔG°f are given as:
ΔG°f (PbBr₂) = -260.75 kj.mol⁻¹
ΔG°f (Pb²⁺) = -24.4 kj.mol⁻¹
ΔG°f (2Br⁻) = -103.97 kj.mol⁻¹
Calculating the standard gibb's free energy using the formula;
ΔG° = ξnpΔG°(product) - ξnrΔG°(reactant)
Substituting, we have;
ΔG° =[1mol*ΔG°f (PbBr₂)] - [1 mol *ΔG°f (Pb²⁺) +2mol *ΔG°f (2Br⁻)]
ΔG° =(1 *-260.75 kj.mol⁻¹) - (1* -24.4 kj.mol⁻¹) +(2*-103.97 kj.mol⁻¹)
= -260.75 + 232.34
= -28.41 kj
Calculating the reaction quotient Q using the formula;
Q = 1/[Pb²⁺ *(Br⁻)²]
= 1/(0.750 * 0.232²)
= 24.77
Substituting all the calculated values into equation 1, we have
ΔG = ΔG° + RTlnQ
ΔG = -28.41 + (8.414*10⁻³ * 298 * In 24.77)
= -28.41 +7.95
= -20. 46 kJ
Therefore, the free energy of reaction = -20.46 kJ
Final answer:
To calculate the reaction free energy ΔG for this reaction, we need to use the standard free energy of formation values given in a data tab, the stoichiometry of the reaction, and the specific conditions of the reaction, including the concentrations of Pb2+ and Br−. After a series of calculations, we will get the ΔG value in joules, which can be converted to kilojoules.
Explanation:
The task here is to calculate the reaction free energy ΔG for the Pb2+(aq) + 2Br−(aq) = PbBr2(s) reaction at 25.0°C. From the given information, we can start by calculating the number of moles of PbBr2 from its mass. Then, referring to the thermodynamic data tab of the ALEKS, we find the standard free energy of formation (ΔGf°) values for Pb2+(aq), Br−(aq), and PbBr2(s). Now, we can use these values and the definition of ΔG for a reaction in terms of ΔGf° values and stoichiometry.
ΔG = ΣΔGf°(products) - ΣΔGf°(reactants).
Note that the equation must be balanced so each ΔGf° value is multiplied by the stoichiometric coefficient of that substance in the reaction. It is also important to remember to convert the answer to kilojoules if the ΔGf° values are given in joules/mole. Lastly, the concentrations of Pb2+ and Br− are included in the reaction quotient Q to show the reaction's non-standard conditions.
Learn more about Reaction Free Energy here:
#SPJ12
Answers
Answer:
Br - C ≡ N
Explanation:
To draw the Lewis line-bond structure we need to bear in mind the octet rule, which states that in order to gain stability each atom tends to share electrons until it has 8 electrons in its valence shell.
- C has 4 e⁻ in its valence shell so it will form 4 covalent bonds.
- Br has 7 e⁻ in its valence shell so it will form 1 covalent bond.
- N has 5 e⁻ in its valence shell so it will form 3 covalent bonds.
The most stable structure that respects these premises is:
Br - C ≡ N
It does not have any H atom.
B. 0.288 g
C. 0.392 g
D. 0.450 g
E. 0.341 g
Answers
Answer: The correct option is E.
Explanation: The reaction between aspirin (also known as acetylsalicylic acid) and sodium hydroxide is known as acid-base titration reaction.
By applying Unitary method, we get:
15.50mL of NaOH dissolves = 0.325 g of aspirin
So, 16.25 mL of NaOH will dissolve = = 0.341 g
Hence, the correct option is E.
b. 8.5 x 10-6 M
c. 6.3 x 10-11 M
d. 1.3 x 10-12 M
e. 5.0 x 10-2 M
f. 1.8 x 10-5 M
Answers
Answer:
c. 6,3x10⁻¹¹M
Explanation:
The solubility of a buffer is defined as the concentration of the dissolved solid in a saturated solution. For the Cd(OH)₂, solubility is:
[Cd²⁺] = S
The dissolution of Cd(OH)₂ is:
Cd(OH)₂ ⇄ Cd²⁺ + 2OH⁻
And the ksp is defined as:
ksp = [Cd²⁺][OH⁻]²
As ksp = 2,5x10⁻¹⁴ and [OH⁻] at pH=12,30 = 10^-(14-12,30) = 0,01995M
2,5x10⁻¹⁴ = [Cd²⁺]×(0,01995M)²
[Cd²⁺] = 6,3x10⁻¹¹M
That means solubility is c. 6,3x10⁻¹¹M
I hope it helps!
Final answer:
The molar solubility of Cd(OH)2 when buffered at a pH of 12.30 can be calculated using the concept of hydrolysis. The correct answer is 6.3 x 10^(-11) M.
Explanation:
To calculate the molar solubility of Cd(OH)2 when buffered at a pH of 12.30, we need to use the concept of hydrolysis. Cd(OH)2 is a slightly soluble salt that undergoes hydrolysis in aqueous solution. At a high pH value, OH- ions react with water to form more OH- ions, shifting the equilibrium towards the hydrolysis reaction.
- First, we write the balanced equation for the hydrolysis reaction: Cd(OH)2(s) ⇌ Cd2+(aq) + 2OH-(aq)
- Since OH- is being produced, we can assume that the concentration of OH- is much greater than that of Cd2+. Therefore, we can ignore the concentration of Cd2+ when calculating the solubility product (Ksp).
- Next, we use the equation for the hydrolysis reaction to write the expression for the solubility product constant (Ksp): Ksp = [Cd2+][OH-]^2
- The concentration of OH- ions in a basic solution is related to the pH by the equation: pOH = 14 - pH
- Using this equation, we can calculate the pOH of the buffered solution: pOH = 14 - 12.30 = 1.70
- Then, we convert the pOH back to OH- concentration: [OH-] = 10^(-pOH) = 10^(-1.70)
- Finally, we substitute the calculated [OH-] into the expression for Ksp to solve for the molar solubility of Cd(OH)2: [Cd(OH)2] = sqrt(Ksp / [OH-]^2)
After performing the calculations, the molar solubility of Cd(OH)2 when buffered at a pH of 12.30 is approximately 6.3 x 10^(-11) M. Therefore, the correct answer is option c. 6.3 x 10^(-11) M.
Learn more about Molar solubility of Cd(OH)2 here:
#SPJ11
Answers
Answer:
a) The wavelength of the baseball is .
b) 9.131 nm is the wavelength of a hydrogen atom at the 43.35 m/s.
Explanation:
Velocity of the baseball = v = 97 mile/hour
1 mile = 1609 meter
1 hour = 3600 seconds
Mass of baseball = m = 0.148 kg
Wavelength of the baseball:
De Broglie wavelength
h =Planck's constant
The wavelength of the baseball is .
b)
Mass of the hydrogen atom =
Velocity of hydrogen atom = u = 43.35 m/s
De Broglie wavelength
9.131 nm is the wavelength of a hydrogen atom at the 43.35 m/s.
Final answer:
To calculate the wavelength of the baseball and hydrogen atom, we can use the wavelength formula. However, the wavelengths calculated are extremely small and cannot be practically detected.
Explanation:
To calculate the wavelength of the baseball, we can use the wavelength formula: λ = v/f. In this case, the velocity (v) of the baseball is given as 97 mph, which is equal to 97 * 1609 m/h. The frequency (f) can be calculated by dividing the speed of light (3 * 10^8 m/s) by the wavelength of the baseball.
For the hydrogen atom, we can use the same formula. However, we need to convert the hydrogen atom velocity to m/s. Once we have the velocity in m/s, we can calculate the wavelength by dividing the velocity by the frequency.
It is important to note that the wavelength calculated for the baseball and hydrogen atom are extremely small and cannot be practically detected by our senses or instruments.
Learn more about Wavelength calculation here:
#SPJ11