Answer: The number of atoms of plutonium present in given number of moles are [tex]3.7\times 10^{24}[/tex]
Explanation:
We are given:
Number of moles of plutonium metal = 6.1 moles
According to mole concept:
1 mole of an element contains [tex]6.022\times 10^{23}[/tex] number of atoms.
So, 6.1 moles of plutonium will contain = [tex]6.1\times 6.022\times 10^{23}=3.7\times 10^{24}[/tex] number of plutonium atoms.
Hence, the number of atoms of plutonium present in given number of moles are [tex]3.7\times 10^{24}[/tex]
Final answer:
To determine the number of plutonium atoms in 6.1 moles, multiply 6.1 by Avogadro's number (6.022 x 10^23 atoms/mole), yielding 3.673 x 10^24 atoms of plutonium in scientific notation.
Explanation:
The question asks how many plutonium atoms are present in 6.1 moles of plutonium metal. To find this, we use Avogadro's number, which is 6.022 × 1023 atoms/mole. This means there are 6.022 × 1023 atoms of any element per mole of that element.
To calculate the total number of atoms in 6.1 moles of plutonium, you multiply the number of moles by Avogadro's number:
Number of atoms = 6.1 moles × 6.022 × 1023 atoms/mole
This calculation gives you the answer in scientific notation: 3.673 × 1024 atoms of Pu.
What is the molar concentration of a solution with 44 grams of CO2 in 0.5 liter solution? a) 2 mole/liter b) 4 mole/liter c) 1 mole/liter d) 3 mole/liter
Answer: The correct answer is Option a.
Explanation:
To calculate the molarity of solution, we use the equation:
[tex]\text{Molarity of the solution}=\frac{\text{Mass of solute}}{\text{Molar mass of solute}\times \text{Volume of solution (in L)}}[/tex]
We are given:
Mass of solute (carbon dioxide) = 44 g
Molar mass of carbon dioxide = 44 g/mol
Volume of solution = 0.5 L
Putting values in above equation, we get:
[tex]\text{Molarity of solution}=\frac{44g}{44g/mol\times 0.5L}\\\\\text{Molarity of solution}=2mol/L[/tex]
Hence, the correct answer is Option a.
Be sure to answer all parts. Calculate the number of g of O, that will react with 9.98 mol of CzHg. Enter your answer in scientific notation. The balanced equation is: C3H2(g) + 502(g) → 3C02(g) + 4H2O(g). * 10 (select) A go,
Answer: The mass of oxygen reacted is [tex]1.60\times 10^{3}g[/tex]
Explanation:
We are given:
Moles of propane = 9.98 mol
For the given chemical equation:
[tex]C_3H_8(g)+5O2(g)\rightarrow 3CO_2(g)+4H_2O(g)[/tex]
By Stoichiometry of the reaction:
1 mole of propane reacts with 5 moles of oxygen.
So, 9.98 moles of propane will react with = [tex]\frac{5}{1}\times 9.98=49.9mol[/tex] of oxygen.
To calculate the mass of carbon dioxide, we use the equation:
[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex]
Moles of oxygen = 49.9 moles
Molar mass of oxygen gas = 32 g/mol
Putting values in above equation:
[tex]49.9mol=\frac{\text{Mass of oxygen}}{32g/mol}\\\\\text{Mass of oxygen}=(49.9mol\times 32g/mol)=1596.8g=1.60\times 10^{3}g[/tex]
Hence, the mass of oxygen reacted is [tex]1.60\times 10^{3}g[/tex]
Write a balanced equation for the neutralization of potassium hydroxide by phosphoric acid. Use the smallest possible integer coefficients. Submit Answer & Next
Explanation:
Neutralization reaction -
The reaction of an acid and base to yield a salt and water , is a type of neutralization reaction .
The reaction of potassium hydroxide and phosphoric acid is a type of neutralization reaction ,
Hence , the reaction is as follows -
KOH (aq) + H₃PO₄ (aq) ----> K₃PO₄ (aq) + 3H₂O (l)
The reaction after balancing the atoms on the reactant side and on the product side is -
3 KOH (aq) + H₃PO₄ (aq) ----> K₃PO₄ (aq) + 3H₂O (l)
The activation energy, Ea, for the reaction 2 N2O5 (g) LaTeX: \longrightarrow ⟶ 4 NO2 (g) + O2 (g) is 22 kJ/mol. What is the rate constant at 84.8°C if the rate constant is 1.868 sec-1 at 16.6°C? Enter to 3 decimal places. LaTeX: \ln\frac{k2}{k1}=\frac{Ea}{R}\left(\frac{1}{T1}\:-\frac{1}{T2}\right)
Answer:
The rate constant [tex]k_{2}[/tex] at 84.8°C is [tex]k_{2}=6.423sec^{-1}[/tex]
Explanation:
Taking the Arrhenius equation we have:
[tex]ln\frac{k_{2}}{k_{1}}=\frac{E_{a}}{R}(\frac{1}{T_{1}}-\frac{1}{T_{2}})[/tex]
Where [tex]k_{2}[/tex] is the rate constant at a temperature 2, [tex]k_{1}[/tex] is the rate constant at a temperature 1; [tex]T_{1}[/tex] is the temperature 1, [tex]T_{2}[/tex] is the temperature 2, R is the gas constant and [tex]E_{a}[/tex] is the activation energy.
Now, we need to solve the equation for [tex]k_{2}[/tex], so we have:
[tex]ln\frac{k_{2}}{k_{1}}=\frac{E_{a}}{R}(\frac{1}{T_{1}}-\frac{1}{T_{2}})[/tex]
[tex]ln({k_{2})-ln(k_{1})=\frac{E_{a}}{R}(\frac{1}{T_{1}}-\frac{1}{T_{2}})[/tex]
[tex]ln(k_{2})=E_{a}(\frac{1}{T_{1}}-\frac{1}{T_{2}})+ln(k_{1})[/tex]
Then we need to make sure that we are working with the same units, so:
[tex]R=8.314\frac{J}{mol.K}[/tex]
[tex]T_{1}=16.6^{o}C+273.15=289.75K[/tex]
[tex]T_{2}=84.4^{o}C+273.15=357.95K[/tex]
And now we can replace the values into the equation:
[tex]ln(k_{2})=\frac{22000\frac{J}{mol}}{8.314\frac{J}{mol.K}}(\frac{1}{289.75K}-\frac{1}{357.95K})+ln(1.868sec^{-1})[/tex]
[tex]ln(k_{2})=2646.139K(0.003451K^{-1}-0.002794K^{-1})+0.6249[/tex]
[tex]ln(k_{2})=2.363sec^{-1}[/tex]
To solve the ln we have to apply e in both sides of the equation, so we have:
[tex]e^{ln(k_{2})}=e^{2.363}sec^{-1}[/tex]
[tex]k_{2}=6.423sec^{-1}[/tex]
Answer:
10.37 s-1
Explanation:
From
k= A e-^Ea/RT
Given
Ea=22KJmol-1
T=16.6+273= 289.6K
k= 1.868 sec-1
R= 8.314JK-1mol-1
A???
Hence
A= k/e^-Ea/RT
A= 1.868/e-(22000/8.314×289.6)
A= 1.7 ×10^4
Substitute into to find k at 84.8°C
k= 1.7×10^4× e-(22000/8.314×357.8)
k=10.37 s-1
Two mercury manometers, one open-end and the other sealed-end, are attached to an air duct. The reading on the open-end manometer is 25 [mm] and that on the sealed-end manometer is 800 [mm]. Determine the absolute pressure in the duct, the gauge pressure in the duct, and the atmospheric pressure, all in (mm Hg).
Answer:
Pressure in duct = 799.75 mmHg
Atmospheric pressure = 774.75 mmHg
Gauge pressure = 24.99 mmHg
Explanation:
First of all, it is needed to set a pressure balance (taking in account that diameter of manometer is constant) in the interface between the air of the duct and the fluid mercury.
From the balance in the sealed-end manometer, we have the pressure of air duct as:
[tex]P = \rho g h_1[/tex]
We have that ρ is density of mercury and g is the gravity
[tex]\rho = 13600 kg/m^{3}[/tex]
[tex]g = 9.8 m/s^{2}[/tex]
So, replace in the equation:
[tex]P = (13600 kg/m^{3} )(9.8 m/s^{2})(800 mmHg)(\frac{1 mHg}{1000 mmHg})[/tex]
[tex]P = 106624.0 \frac{kg}{s^{2}} = 106624.0 Pa[/tex]
Transforming from Pa to mmHg
[tex]P = 106624.0 Pa (\frac{760 mmHg}{101325 Pa}) = 799.7 mmHg[/tex]
From the balance in the open-end manometer, we have the pressure of air duct as:
[tex]P = \rho g h_2 + P_atm[/tex]
Isolate [tex]P_atm[/tex]:
[tex]P_atm = P - \rho g h_2[/tex]
Calculating:
[tex]P_atm = 799.75 mmHg - (13600 kg/m^{3} )(9.8 m/s^{2})(25 mmHg)(\frac{1 mHg}{1000 mmHg})(\frac{760 mmHg}{101325 Pa} )[/tex]
[tex]P_atm = 774.75 mmHg[/tex]
Finally, gauge pressure is the difference between duct pressure and atmospheric pressure, so:
[tex]P_gau = P - Patm[/tex]
[tex]P_gau = 799.75 mmHg - 774.75 mmHg[/tex]
[tex]P_gau = 24.99 mmHg[/tex]
End.
Calculate the wavelength in nm of ultraviolet light with frequency of 5.5 x 10¹⁵ Hz.
Answer: Wavelength of ultraviolet light is 54 nm.
Explanation:
Electromagnetic wave is defined as the wave which is associated with both electrical and magnetic component associated with them. They can travel in vacuum as well and travel with the speed of light.
The relationship between wavelength and frequency of the wave follows the equation:
[tex]\nu=\frac{c}{\lambda}[/tex]
where,
[tex]\nu[/tex] = frequency of the wave =[tex]5.5\times 10^{15}Hz[/tex]
c = speed of light =[tex]3\times 10^8ms^{-1}[/tex]
[tex]\lambda [/tex] = wavelength of the wave
Putting in the values we get:
[tex]5.5\times 10^{15}s^{-1}=\frac{3\times 10^8ms^{-1}}{\lambda}[/tex]
[tex]\lambda=0.54\times 10^{-7}m[/tex]
[tex]1nm=10^{-9}m[/tex]
[tex]\lambda=54nm[/tex]
Thus wavelength of ultraviolet light is 54 nm.
Based upon the information provided in the class, which of the following bond types is the strongest? Question options:
A) hydrogen bond
B) Ion - Dipole
C) Dipole - Dipole
D) Ion - Induced Dipole
E) Dipole - Induced Dipole
Answer: A hydrogen bonding is interaction between lone pair and hydrogen atom. An Ion-Dipole interaction is the interaction between an ion formed and a dipole. Dipole forms because of the electronegativity difference between two atom participating in the bond formation, and an ion is formed when an atom gains or lose electron. This ion-dipole interaction is strongest interaction.
Therefore, The right choice is (B)
What is the sum of the coefficient when the following equation is balanced:
__ H2SO4 + __ NaOH → __ H2O + __ Na2SO4
a. 4
b. 5
c. 6
d. no right answer
Answer:
The sum of the coefficient is: 1 + 2 +2 + 1 = 6 ( option c)
Explanation:
First we will balance on both sides Na
On the right side we have 2x Na but on the left side we have only 1x Na. So we have to multiply NaOH on the left side by 2.
This will give us:
H2SO4 + 2 NaOH → H2O + Na2SO4
Now we have on both sides 2x Na
We see that on the left side we have 4x H ( 2x H of H2SO4 and 2x H of NaOH), but on the right side we only have 2x H. So, we have to multiply H2O on the right side by 2.
This will give us:
H2SO4 + 2 NaOH → 2 H2O + Na2SO4
Now we have on both sides 2x Na and 4x H.
Also the number of O is on both sides equal, due to this. ( Both sides have 6x O).
Finally, we have this reaction: H2SO4 + 2 NaOH → 2 H2O + Na2SO4
The sum of the coefficient is: 1 + 2 +2 + 1 = 6 ( option c)
Final answer:
The sum of the coefficients when the equation H2SO4 + NaOH → H2O + Na2SO4 is balanced is 6. The balanced equation is 1 H2SO4 + 2 NaOH → 2 H2O + 1 Na2SO4.
Explanation:
The sum of the coefficients when the chemical equation H2SO4 + NaOH → H2O + Na2SO4 is balanced is the total of the numbers that are used to balance the equation.
To balance the equation, we need to ensure that there is the same number of each type of atom on both the reactant and product sides of the equation. In this case, we balance the equation as follows: 1 H2SO4 (aq) + 2 NaOH (aq) → 2 H2O (l) + 1 Na2SO4 (aq). So, the coefficients in the balanced equation are 1, 2, 2, and 1 respectively.
Adding these coefficients, we get:
1 (for H2SO4) + 2 (for NaOH) + 2 (for H2O) + 1 (for Na2SO4) = 6.
The answer is option c: 6.
Which of the following is a property of a mixture? It consists of a single element or compound. Components that are mixed can be in different states of matter. It is very difficult to separate the components. The proportion of the particles that make it up cannot be altered.
Answer:
Components that are mixed can be in different states of matter.
Explanation:
A mixture is often described as an impure substance. It has the following properties:
Constituents retain their identities i.e the physical properties of mixtures are retained. Their composition is indefinite i.e they consist of two or more elements and/or compounds in any proportion by mass. They can easily be seperated by physical methods.There are two types of mixture; homogenous mixtures have their constituents existing in one phase.
Heterogenous mixtures have constituents in different phases. The phases are the different states of matter.
One of the properties of a mixture is that; Components that are mixed can be in different states of matter.
Definition;
A mixture put simply can be defined as an impure substance which is made up of different constituents with each constituent possessing its own unique properties.
Additionally, mixtures are subdivided into homogeneous and heterogeneous mixtures;
A homogeneous mixture has it's constituent substances in the same phase/state.An heterogenous mixture on the other hand, has it's constituent substances in different states of matter.Read more;
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This experiment involves the reaction of Ba(OH)2 with H2SO4. Which of the following gives the balanced chemical reaction used in the experiment?
Ba(OH)2 (aq) + H2SO4(aq) → H2Ba(s) + SO4(OH)2(l)
Ba(OH)2 (aq) + H2SO4(aq) → BaSO4(s) + H2O(l)
BaSO4(s) + 2 H2O(l) → Ba(OH)2 (aq) + H2SO4(aq)
Ba(OH)2 (aq) + H2SO4(aq) → BaSO4(s) + 2 H2O(l)
Answer:
Ba(OH)2 (aq) + H2SO4(aq) → BaSO4(s) + 2 H2O(l)
That's the right one.
Explanation:
You should see that this equation is balanced, not as
Ba(OH)2 (aq) + H2SO4(aq) → BaSO4(s) + H2O(l)
(on reactive we have 4 H, on products, we have only 2)
Ba(OH)2 (aq) + H2SO4(aq) → H2Ba(s) + SO4(OH)2(l)
(this is impossible, it's a nonsense)
BaSO4(s) + 2 H2O(l) → Ba(OH)2 (aq) + H2SO4(aq)
(it is the same with the right one but is the other way around. The statement says, reaction of Ba(OH)2 with H2SO4, not BaSO4 with water. Also, it is not a chemical balance.
A chemist adds 0.45 L of a 1.08 * 10M zinc oxalate (ZnC,0) solution to a reaction flask. Calculate the mass in milligrams of incolate the chemist has added to the flask. Be sure your answer has the correct number of significant digits.
Answer: The mass of zinc oxalate, the chemist has added is [tex]7.6\times 10^5mg[/tex]
Explanation:
To calculate the mass of solute, we use the equation used to calculate the molarity of solution:
[tex]\text{Molarity of the solution}=\frac{\text{Mass of solute}}{\text{Molar mass of solute}\times \text{Volume of solution (in L)}}[/tex]
We are given:
Molarity of solution = [tex]1.08\times 10M=10.8M[/tex]
Molar mass of zinc oxalate = 155.4 g
/mol
Volume of solution = 0.45 L
Putting values in above equation, we get:
[tex]10.8M=\frac{\text{Mass of zinc oxalate}}{155.4g/mol\times 0.45L}\\\\\text{Mass of zinc oxalate}=(10.8mol/L\times 155.4g/mol\times 0.45L)=7.6\times 10^2g[/tex]
To convert the calculated mass into milligrams, we use the conversion factor:
1 g = 1000 mg
So, [tex]7.6\times 10^2g\times \frac{1000mg}{1g}=7.6\times 10^5mg[/tex]
Hence, the mass of zinc oxalate, the chemist has added is [tex]7.6\times 10^5mg[/tex]
Compute (4.29×1015)⋅(1.96×10−4).
Express your answer to three digits.
Answer:
(4.29×10¹⁵)⋅(1.96×10⁻⁴) = 8.40 × 10¹¹, has three significant digits.
Explanation:
To solve: (4.29×10¹⁵)⋅(1.96×10⁻⁴)
According to the product rule of exponents, when exponents having the same base are multiplied, the base is kept the same and the powers are added.
Therefore,
(4.29×10¹⁵)⋅(1.96×10⁻⁴) = (4.29 × 1.96) · 10⁽¹⁵⁻⁴⁾ = 8.40 × 10¹¹
The number, 8.40 × 10¹¹ has three significant digits.
To calculate the product of (4.29×1015) and (1.96×10−4), multiply the significant figures to get 8.4084, then add the exponents to get 1011, and combine them to express the product in scientific notation as 8.41×1011, rounded to three digits.
Explanation:
To compute the product of (4.29×1015) and (1.96×10−4), you multiply the significant figures and then add the exponents of 10. First, multiply the significant figures:
4.29 × 1.96 = 8.4084.
Next, add the exponents:
1015 × 10−4 = 1015−4 = 1011.
Combine the significant figure product with the exponent sum to express the answer in scientific notation:
8.4084 × 1011 → 8.41×1011 (rounded to three digits).
Be sure to answer all parts. Caffeine occurs naturally in coffee and tea, and is present in many soft drinks. The formula of caffeine is C,H1N402. Calculate the formula mass and molar mass of caffeine. Formula mass = amu Molar mass = g/mol
Answer: The formula mass of caffeine is 97 amu and molar mass of caffeine is 194 g/mol
Explanation:
Formula mass is defined as the sum of the mass of all the atoms each multiplied its atomic masses that are present in the empirical formula of a compound. It is expressed in amu.
Molar mass is defined as the sum of the mass of all the atoms each multiplied its atomic masses that are present in the molecular formula of a compound. It is expressed in g/mol.
Empirical formula is defined as the formula in which atoms in a compound are present in simplest whole number ratios.
The molecular formula of caffeine is [tex]C_8H_{10}N_4O_2[/tex]
Dividing each number of atoms by '2', we will get the empirical formula of caffeine. The empirical formula of caffeine is [tex]C_4H_5N_2O[/tex]
We know that:
Atomic mass of carbon = 12 amu
Atomic mass of hydrogen = 1 amu
Atomic mass of nitrogen = 14 amu
Atomic mass of oxygen = 16 amu
Formula mass of caffeine = [tex](4\times 12)+(5\times 1)+(2\times 14)+(1\times 16)]=97amu[/tex]
Molar mass of caffeine = [tex](8\times 12)+(10\times 1)+(4\times 14)+(2\times 16)]=194g/mol[/tex]
Hence, the formula mass of caffeine is 97 amu and molar mass of caffeine is 194 g/mol
Refer to the following unbalanced equation: CO2 H20 C6H14 O2>CO2 + H2O What mass of oxygen (O2) is required to react completely with 10.4 g of C6H14? D. 36.7 g Selected Answer: D. 36.7 g Correct Answer:
Answer: The mass of oxygen gas required is 36.7 grams.
Explanation:
To calculate the number of moles, we use the equation:
[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex] .....(1)
Given mass of hexane = 10.4 g
Molar mass of hexane = 86.18 g/mol
Putting values in equation 1, we get:
[tex]\text{Moles of hexane}=\frac{10.4g}{86.18g/mol}=0.12mol[/tex]
The chemical equation for the combustion of hexane follows:
[tex]2C_6H_{14}+19O_2\rightarrow 12CO_2+14H_2O[/tex]
By stoichiometry of the reaction:
2 moles of hexane reacts with 19 moles of oxygen gas
So, 0.12 moles of hexane will react with = [tex]\frac{19}{2}\times 0.12=1.14mol[/tex] of oxygen gas.
Now, calculating the mass of oxygen gas by using equation 1, we get:
Molar mass of oxygen gas = 32 g/mol
Moles of oxygen gas = 1.14 moles
Putting values in equation 1, we get:
[tex]1.14mol=\frac{\text{Mass of oxygen gas}}{32g/mol}\\\\\text{Mass of oxygen gas}=36.7g[/tex]
Hence, the mass of oxygen gas required is 36.7 grams.
Examining a chemical system before and after a reaction reveals the a. net chemical change. b. reaction mechanism. c. intermediates. d. activated complex
Answer: Option (a) is the correct answer.
Explanation:
A chemical change is defined as the change which brings difference in the composition of reacting species.
Therefore, during a chemical change there will always be formation of new compounds.
For example, [tex]2Na + Cl_{2} \rightarrow 2NaCl[/tex] is a chemical change as new substance formed is NaCl.
So basically, a chemical reaction equation or system tells the overall change occuring in the system.
Mechanism of a reaction can only be determined theoretically and not just by examining a chemical system.
Intermediates cannot be isolated as they are very reactive species. Hence, they cannot be determined by examining a chemical system.
Activated complex are the intermediate substances which are formed during the reaction and they cannot be isolated. Hence, they cannot be determined by examining a chemical system.
Thus, we can conclude that examining a chemical system before and after a reaction reveals the net chemical change.
If an athlete runs at a speed of 12.9 km/hour, how long will it take the athlete to run a marathon (about 42.2 km)? Express your answer in hours using the correct number of significant figures. Do not enter your answer using scientific notation.
Answer:
Time = 3.27s
Explanation:
Time = Distance / Speed
Time = 42.2 / 12.9 = 3.2713
When you multiply the number of significant figures in the result is the same as the number with the least significant figures.
In this case 42.2 has 3 significant figures and 12.9 also has 3 significant figures, therefore the answer must have 3 significant figures too.
Time = 3.27 s
If the density of alcohol is 0.79 g/mL, what is the mass in grams of 1.0 L of alcohol?
Answer: The mass of alcohol is 790 grams.
Explanation:
To calculate the mass of alcohol, we use the equation:
[tex]\text{Density of substance}=\frac{\text{Mass of substance}}{\text{Volume of substance}}[/tex]
Volume of alcohol = 1.0 L = 1000 mL (Conversion factor: 1 L = 1000 mL)
Density of alcohol = 0.79 g/mL
Putting values in above equation, we get:
[tex]0.79g/mL=\frac{\text{Mass of alcohol}}{1000mL}\\\\\text{Mass of alcohol}=790g[/tex]
Hence, the mass of alcohol is 790 grams.
Final answer:
The mass of 1.0 L of alcohol is 790 grams.
Explanation:
To calculate the mass in grams of 1.0 L of alcohol, you can use the density of alcohol.
The given density is 0.79 g/mL.
This means that for every 1 mL of alcohol, there is a mass of 0.79 grams.
Since 1 L is equal to 1000 mL, you can multiply the density by the volume to find the mass: 0.79 g/mL × 1000 mL = 790 grams of alcohol.
List the substances Ar, Cl2, CH4, and CH3COOH, in order of increasing strength of intermolecular attractions. List the substances , , , and , in order of increasing strength of intermolecular attractions. CH4 < Ar< CH3COOH < Cl2 CH3COOH < Cl2 < Ar < CH4 Ar < Cl2 < CH4 < CH3COOH Cl2 < CH3COOH < Ar < CH4 CH4 < Ar < Cl2 < CH3COOH
The substances Ar, Cl2, CH4, and CH3COOH can be ranked in increasing order of strength of intermolecular attractions as CH4 < Ar < Cl2 < CH3COOH.
Explanation:The intermolecular forces in the given substances can be ranked from weakest to strongest as follows:
Ar - Argon: The intermolecular force in Argon is London dispersion force, which is the weakest type of intermolecular force.Cl2 - Chlorine: Chlorine is a diatomic molecule and the intermolecular force here is also London dispersion force.CH4 - Methane: Methane has a tetrahedral molecular shape and the only intermolecular force present is London dispersion force.CH3COOH - Acetic Acid: Acetic acid contains a polar functional group -COOH which allows it to form dipole-dipole interactions, making it the substance with the strongest intermolecular attractions.A dark-adapted human eye at the peak of its sensitivity (510 nm) can perceive a flash when 3.5 x 1015 J of energy enter the iris. How many photons is this? (In fact only 10% of these are absorbed by the retina.)
Answer:
In 3.5 x 10^(15) J of energy there are 9*10^(33) photons.
Explanation:
To solve this problem, we need two equations.
The equation of light velocity, wich is a relation between wavelenght and frecuency.
c=λν (1)
where:
c: speed of light = 3 × 10^8 [m/s] ν: frecuency [1/s]λ: wavelenght of wave [m]The Photoelectric Effect equation, that refers to the energy absorbed or emanate by ONE photon.
E = hν (2)
where:
h : Planck´s constant = 6,626*10^{-34} [J.s]ν: frecuency of radiation [s]Ef: energy of one photon [J]The first we do is to calculate the frecuency of the flash using equation (1). The wavelenght of the flash is 510 nm = 510 * 10^(-9) m
c=λν........................ ν= c/λ = 3 × 10^8 [m/s]/ 510 * 10^(-9) m = 5,88 * 10^(14) 1/s
Note: small wavelenghts always have big frequencies
Now, we use the photoelectric effect equation to calculate the amount of energy that ONE photon can abosrb.
E = hν ..................... E = 6,626*10^{-34} [J.s] * 5,88 * 10^(14) 1/s =3,9 * 10^(-19) J
To know the number of photons, we just have to divide the TOTAL amount of energy between the energy of ONE photon. So:
# photons = 3.5 x 10^(15) J / 3,9 * 10^(-19) J = 9*10^(33) photons.
write a reaction to describe the behavior of the following substances in water. please include all phases.
NF3 (gas)
CH2CH2 (g)
3NF3 + 5H2O → HNO3 + 2NO + 9HF
Nitrogen fluoride reacts with water to produce nitric acid, nitric oxide, and hydrogen fluoride. The reaction slowly takes place in a boiling solution.
CH2CH2 + H2O → CH3CH2OH
Ethylene is a hydrocarbon with water that creates ethanol and ethanol is an alcohol
The vapour pressure of pyridine is 50.0kPa at 365.7K and the
normal boiling point is 388.4 K. What is theenthalpy of
vaporization of pyridine?
The enthalpy of vaporization for pyridine can be calculated using the Clausius-Clapeyron equation. Given that the vapor pressure of pyridine is 50.0 kPa at 365.7 K, and its boiling point is 388.4K, we can substitute these values into the equation to find the enthalpy of vaporization.
Explanation:The question is asking for the enthalpy of vaporization of pyridine. We first need to apply the Clausius-Clapeyron equation which is
ln(P2/P1) = -ΔHvap/R *(1/T1 - 1/T2), where P2 is the vapor pressure at the boiling point (1.00 atm or 101.3 kPa), P1 is the given vapor pressure (50.0 kPa), ΔHvap is the enthalpy of vaporization which we want to find, R is the gas constant (8.314 J/K.mol), T1 is 365.7 K, and T2 is the boiling point (388.4 K). By rearranging and substituting the values into the equation, one can solve for ΔHvap to find its value. Remember always to convert the pressure units into the same, in this case we used kilopascal.
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A chemist prepares a solution of potassium permanganate (KMnO4) by measuring out 3.8 umol of potassium permanganate into a 100 mL volumetric flask and filling the flask to the mark with water. Calculate the concentration in mol/L of the chemist's potassium permanganate solution. Round your answer to 2 significant digits. x 5 ? Explanation Check
Answer:
3,8×10⁻⁵ mol/L of potassium permanganate solution
Explanation:
To calculate concentration in mol/L you must convert the 3,8 umol to moles and 100 mL to liters, knowing 1 umol are 1×10⁻⁶mol and 1L are 1000 mL.
3,8 umol × (1×10⁻⁶mol / 1 umol ) = 3,8×10⁻⁶mol of potassium permanganate.
100 mL × ( 1L / 1000 mL) = 0,100 L
Thus, concentration in mol/L is:
3,8×10⁻⁶mol / 0,100 L = 3,8×10⁻⁵ mol/L of potassium permanganate solution
I hope it helps!
Final answer:
The concentration of the potassium permanganate solution is 3.8 x 10⁻⁵ M when rounded to two significant digits.
Explanation:
The concentration of a solution is calculated by dividing the number of moles of the solute by the volume of the solution in liters. To calculate the concentration of potassium permanganate (KMnO₄) in the chemist's solution, you need to use the equation:
C = n / V
where C is the molarity (concentration) in moles per liter (mol/L), n is the number of moles of KMnO₄, and V is the volume of the solution in liters.
In this case, the student already has 3.8 μmol (or 3.8 x 10⁻⁶ mol) of KMnO₄ and the total volume is 100 mL, which is equivalent to 0.1 L. Therefore, the molarity (C) of the solution is:
C = 3.8 x 10⁻⁶ mol / 0.1 L = 3.8 x 10⁻⁵ M
Thus, the concentration of the potassium permanganate solution is 3.8 x 10⁻⁵ M, which can be rounded to two significant digits as 3.8 x 10⁻⁵ M.
The partial pressure of CO2 gas above the liquid in a carbonated drink is 0.71 atm. Assuming that the Henry's law constant for CO2 in the drink is that same as that in water, 3.7 x 10-2 mol/L atm, calculate the solubility of carbon dioxide in this drink. Give your answer to 3 decimal places.
Answer: The molar solubility of carbon dioxide gas is 0.003 M
Explanation:
Henry's law states that the amount of gas dissolved or molar solubility of gas is directly proportional to the partial pressure of the liquid.
To calculate the molar solubility, we use the equation given by Henry's law, which is:
[tex]C_{CO_2}=K_H\times p_{liquid}[/tex]
where,
[tex]K_H[/tex] = Henry's constant = [tex]3.7\times 10^{-2}mol/L.atm[/tex]
[tex]p_{CO_2}[/tex] = partial pressure of carbonated drink = 0.71 atm
Putting values in above equation, we get:
[tex]C_{CO_2}=3.7\times 10^{-2}mol/L.atm\times 0.71atm\\\\C_{CO_2}=2.637\times 10^{-2}mol/L=0.003M[/tex]
Hence, the molar solubility of carbon dioxide gas is 0.003 M
Answer: The molar solubility of carbon dioxide is [tex]2.63\times 10^{-2}M[/tex]
Explanation:
To calculate the molar solubility, we use the equation given by Henry's law, which is:
[tex]C_{CO_2}=K_H\times p_{CO_2}[/tex]
where,
[tex]K_H[/tex] = Henry's constant = [tex]3.7\times 10^{-2}mol/L.atm[/tex]
[tex]C_{CO_2}[/tex] = molar solubility of carbon dioxide gas = ?
[tex]p_{CO_2}[/tex] = partial pressure of carbon dioxide gas = 0.71 atm
Putting values in above equation, we get:
[tex]C_{CO_2}=3.7\times 10^{-2}mol/L.atm\times 0.71atm\\\\C_{CO_2}=2.63\times 10^{-2}M[/tex]
Hence, the molar solubility of carbon dioxide is [tex]2.63\times 10^{-2}M[/tex]
Describe in detail how to accurately prepare 250.00 mL of a 2.25 M HCl solution from a 12.0 M HCl solution?
Answer:
Take 46.9 ml of the 12 M solution using a graduated cylinder and pour the liquid in a 250-ml volumetric flask. Add water until the mark.
Explanation:
To prepare this solution, you have to take a volume of the 12 M HCl solution and add water to 250 ml. What volume should you take?
The number of moles of HCl present in the volume you take from the concentrated solution will be the same as the number of moles in the final solution since you are only adding water. Then:
number of moles of HCl in the taken volume = number of moles in the final solution.
number of moles of HCl = concentration (in molarity) * volume
Then:
Ci * Vi = Cf * Vf
Where
Ci = the concentration of the solution from which you take the volume to prepare the more diluted solution.
Vi = the volume of the concentrated solution you have to take.
Cf = Concentration of the final solution
Vf = volume of the final solution
Replacing with the data:
12.0 M * Vi = 250.00 ml * 2.25M
Vi = 46.9 ml
According to this reaction, ____ serves as the base. CH3OH + HI --> CH3OH2 +I-
A : CH3OH2+
B : HI
C : CH3OH
D : I-
Answer:
C : CH₃OH
Explanation:
According to the concept of Bronsted - Lowry -
An acid is a substance , that can give a proton .
A base is a substance , that can take a proton .
According to the reaction given in the question ,
CH₃OH + HI --> CH₃OH₂⁺ + I⁻
From , the above reaction ,
It is visible that , the reactant CH₃OH accepts a proton and forms CH₃OH₂⁺ , thereby acting as a base ,
And , HI act as an acid , as is losses a proton and becomes I⁻ .
Hence ,
In the above reaction , CH₃OH act as a base .
What is the concentration of Agt in a 1.2 x 10-4 solution of Ag2CO3? (To write your answer using scientific notation use 1.0E-1 instead of 1.0 x 10-1)
Answer:
2.4E-4
Explanation:
Hello,
By applying the following mass-mole relationship, the concentration could be computed as follows (assuming molarity as long as it isn't specified), since in the silver carbonate two silver molecules are present:
[tex][Ag]=1.2x10^{-4}\frac{molAg_2CO_3}{L} *\frac{2mol Ag}{1 mol Ag_2CO_3}=2.4x10^{-4}\frac{mol Ag}{L}[/tex]
Best regards.
1.00 kg of ice at -10 °C is heated using a Bunsen burner flame until all the ice melts and the temperature reaches 95 °C. A) How much energy in kJ is required to effect this transformation?
Answer : The energy required is, 574.2055 KJ
Solution :
The conversions involved in this process are :
[tex](1):H_2O(s)(-10^oC)\rightarrow H_2O(s)(0^oC)\\\\(2):H_2O(s)(0^oC)\rightarrow H_2O(l)(0^oC)\\\\(3):H_2O(l)(0^oC)\rightarrow H_2O(l)(95^oC)[/tex]
Now we have to calculate the enthalpy change or energy.
[tex]\Delta H=[m\times c_{p,s}\times (T_{final}-T_{initial})]+n\times \Delta H_{fusion}+[m\times c_{p,l}\times (T_{final}-T_{initial})][/tex]
where,
[tex]\Delta H[/tex] = energy required = ?
m = mass of ice = 1 kg = 1000 g
[tex]c_{p,s}[/tex] = specific heat of solid water = [tex]2.09J/g^oC[/tex]
[tex]c_{p,l}[/tex] = specific heat of liquid water = [tex]4.18J/g^oC[/tex]
n = number of moles of ice = [tex]\frac{\text{Mass of ice}}{\text{Molar mass of ice}}=\frac{1000g}{18g/mole}=55.55mole[/tex]
[tex]\Delta H_{fusion}[/tex] = enthalpy change for fusion = 6.01 KJ/mole = 6010 J/mole
Now put all the given values in the above expression, we get
[tex]\Delta H=[1000g\times 4.18J/gK\times (0-(-10))^oC]+55.55mole\times 6010J/mole+[1000g\times 2.09J/gK\times (95-0)^oC][/tex]
[tex]\Delta H=574205.5J=574.2055kJ[/tex] (1 KJ = 1000 J)
Therefore, the energy required is, 574.2055 KJ
A solution contains 0.45 M hydrofluoric acid (HF; KA = 6.8 X 10−4). Write the dissociation reaction. Determine the degree of ionization and the pH of the solution
Answer:
Degree of ionization = 0.0377
pH of the solution = 1.769
Explanation:
Initial concentration of HF = 0.45 M
[tex]K_a = 6.8 \times 10^{-4}[/tex]
[tex]HF \leftrightharpoons H^+ + F^-[/tex]
Initial 0.45 0 0
At equi 0.45 - x x x
Equilibrium constant = [tex]\frac{[H^+][F^-]}{HF}[/tex]
[tex]6.8 \times 10^{-4}= \frac{[x][x]}{0.45 - x}[/tex]
[tex]x^2 + 6.8 \times 10^{-4} x - 6.8 \times 10^{-4} \times 4.5 = 0[/tex]
x = 0.017 M
x = Cα
α = Degree of ionization
C = Concentration
Degree of ionization = [tex]\frac{0.017}{0.45} = 0.0377[/tex]
[tex]pH = -log[H^+][/tex]
[H^+]=0.017 M
[tex]pH = -log[0.017][/tex]
= 1.769
Final answer:
The acid dissociation reaction for hydrofluoric acid in water is [tex]HF (aq) + H_2O (l)[/tex] ⇌ [tex]H_3O^+ (aq) + F- (aq)[/tex]. The concentration of a 0.1 L solution containing 0.05 g of HF is 0.025 M. To find the pH for such a solution using the given Ka, the ICE table method can be utilized.
Explanation:
To answer your questions regarding hydrofluoric acid (HF) and its properties, we can proceed as follows:
a) Write out the acid dissociation reaction for hydrofluoric acid. Label the conjugate acid/base pairs.
Hydrofluoric acid dissociates in water as follows:
[tex]HF (aq) + H_2O (l)[/tex] ⇌ [tex]H_3O^+ (aq) + F- (aq)[/tex]
In this reaction, HF is the conjugate acid and F- is the conjugate base.
b) What is the concentration (M) of a solution containing 0.05 g of HF in 0.1 L H2O?
The molecular weight of HF is approximately 20.01 g/mol. To find the molarity, first convert grams to moles:
0.05 g HF × (1 mol HF/20.01 g HF) = 0.0025 mol HF
Then, divide the moles of HF by the volume of the solution in liters:
0.0025 mol HF / 0.1 L = 0.025 M
c) Using the given Ka value, calculate the pH of the solution from part b
Since HF is a weak acid, and given that Ka = 7.2 × [tex]10^-^4[/tex], you can use the ICE table method to find the concentration of H3O+ and then calculate the pH.
List some of the important biological functions of carbohydrates
Answer:
Carbohydrates are the biological molecules having a general emperical formula [tex]C_{m} (H_{2} O)_{n}[/tex].
There are various important biological functions of carbohydrates. Carbohydrates serve as structural components, component of coenzymes, and backbone of RNA. Carbohydrates provide and store energy, and also plays important role in blood clotting, development, immune system, and preventing pathogenesis.
How do you determine the environmental impact of human activities?
Answer:
Environment refers to everything that surrounds an individual and interacts between them. The factors that control the environment can be biotic and abiotic.
Humans have greatly affected the environment. Some of the ways in which the environment is affected by humans are as follows-
(1) Humans have constructed industries and factories that have released a huge amount of toxic gases into the atmosphere.
(2) These harmful gases have increased the earth's global temperature. As a result of which the global warming effect has increased.
(3) The waste materials eliminated from these industries mix with the rivers and streams and pollute the water. It degrades water quality.
(4) The fossil fuels are exhausted at a very high rate.
(5) The spilling of the oils in the oceans has affected the marine species drastically.
(6) Due to the extensive mining at different places, soil fertility has decreased considerably.
(7) Cutting down trees for settlement purposes and other infrastructures.
The environmental impact of human activities can be measured using the Ecological Footprint model, which calculates the resources consumed and waste generated by our actions. The Precautionary Principle is critical when understanding environmental effects is limited, advocating for caution. Reducing our carbon footprint through simple tasks like walking instead of driving can greatly contribute to environmental health.
Explanation:To determine the environmental impact of human activities, one can use the Ecological Footprint model developed by William Rees and Mathis Wackernagel. This model measures the amount of biologically productive land and water area required to produce the resources a person, population, or activity consumes and to absorb the waste they generate, given prevailing technology and resource management practices.
Appraising the ways in which human intervention has altered the environment often leads to a blurred line between 'natural' and human-influenced ecosystems. One principle to consider when the effects of an activity on the environment are not well understood is the Precautionary Principle. This suggests that in the absence of clear data, we must assume that harm to the environment could occur and therefore proceed cautiously with any such activities.
Individual choices, like walking instead of driving, can lead to reducing one's overall carbon footprint. This collective effort is critical as it can mitigate some of the negative impacts humans have on the environment, including air pollution, which is significantly attributed to human activity such as transport and industrial processes. Moreover, adjusting consumption patterns and holding corporations accountable for environmental degradation are also key steps towards sustainability.