The number of photons having a wavelength of 16.0 um required to produce 2.3KJ of energy is 1.85 x 10¹⁹
What are photons?Photons are defined as a basic particle that is both the force carrier for the electromagnetic force and a quantum of the electromagnetic field, which includes electromagnetic radiation like light and radio waves.
It can also be defined as a discrete bundle of electromagnetic energy is what is known as a light particle.
Energy = 2.3 KJ
Wavelength = 16.0 x 10⁶ m
Energy = hc / ∧
= 6.63 x 10²⁴ x 3 x 10³ / 16.0 x 10⁶
= 1.24 x 10¹⁹ J
Number of photons used = 2.3 KJ / 1.24 x10¹⁹
= 1.85 x 10¹⁹
Thus, the number of photons having a wavelength of 16.0 um required to produce 2.3KJ of energy is 1.85 x 10¹⁹
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A saturated solution of MgF2 is prepared at 27°C. After equilibrium has been reached, the concentrationof magnesium ions in the solution is found to be 1.2 x 10-3 M. Type in the correct values for A and B inthe ICE table.A:Mg2+(aq)2F (aq)1SolidAMBMB:DONEс-Dissolvedsolid+?M+?MELess solid?M?MIntro
Answer:
A: 0
B: 0
Explanation:
Initially the concentration of Mg+2 ions and F- ions is zero. The ICE table is:
Using 0.082 as your R value, what mass of NaN3 is required to produce 10L of N2 gas, at 273K and 1.5atm. Show all your work completely.Use the following formula to guide your work: 2NaN3 -> 2Na + 3 N2
To solve this question, we need to use the Clapeyron formula.
Clapeyron's formula is a mathematical expression that relates quantities such as pressure (P), volume (V), temperature (T) and the number of particles (n) that make up an ideal gas.
The formula is: PV = nRT
First, let's discover the number in moles of N2. We have:
P = 1.5 atm
V = 10 L
n = ???
R = 0.082 atm.L/mol.k
T = 273 K
1.5 x 10 = n x 0.082 x 273
15 = n x 22.386
n = 15/22.386
n = 0.67 moles
As we can see in the chemical reaction equation, the ratio between NaN3 and N2 is 2:3.
So:
2 mol of NaN3 --- 3 mol of N2
x mol of NaN2 --- 0.67 moles
3x = 2 x 0.67
x = 0.45 moles of NaN3
Now we transform this value into grams, using NaN3 formula mass, which is 65 g/mol:
65 g ---- 1 mol
x g ---- 0.45 mol
x = 29 g
Answer: 29 g of NaN3
How do you solve the decomposition of aluminum oxide?
Aluminum Oxide decomposes to Aluminum metal and Oxygen gas.
- First, write down each compound:
[tex]Al_2O_3\longrightarrow Al+O_2[/tex]- Second, write the number of moles of each compound, so that we have the same amount of reactants as products. Here, it is important not to change the subscript of compound elements.
For example, let's start by adding a number 2 in front of the aluminum metal to balance:
[tex]Al_2O_3\text{ }\rightarrow2Al+O_2[/tex]So far, the amount of aluminum has been balanced but the amount of oxygen is unbalanced, so let's add a number 3 for the oxygen gas.
[tex]Al_2O_3\text{ }\rightarrow2Al+3O_2\text{ }[/tex]Now, to have the same amount of moles of oxygen on both sides, let's put a number 2 in the aluminum oxide:
[tex]2Al_2O_3\text{ }\rightarrow2Al+3O_2[/tex]Here, the amount of aluminum moles is unbalanced, so we add a number 4 for the aluminum metal to balance:
[tex]2Al_2O_3\text{ }\rightarrow4Al+3O_2[/tex]- This is the final balanced equation of decomposition of aluminum oxide:
[tex]\begin{gathered} 2Al_2O_3\text{ }\rightarrow4Al+3O_2 \\ \end{gathered}[/tex]Write the complete ground-state electron configuration of Mn⁴⁺.
The complete ground-state electronic configuration of Mn⁺⁴ is:
Mn⁺⁴: [Ar] 4s⁰ 3d³
The electronic configuration is written according to the following principles:
Aufbau's rulePauling's exclusion principleHund's rule of maximum multiplicityManganese being a d-block element possesses d-orbitals in the electron cloud. There are 25 electrons present in the ground-state configuration.
In order to reach the excited state, electrons will be removed from the ground state. The removal of electrons is centripetal in nature. Initially, 2 electrons will be removed from 4s, followed by the removal of 2 electrons from 3d.
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Farmers use primarily two fertilizers - ammonium nitrate and ammonium phospate. Which contains a greater percentage of nitrogen by mass? Write the formula for ammonium nitrate:-----------------------------------------------------------||________________________________First, let's add up the total molar mass of ammonium nitrate below:-----------------------------------------------------------||________________________________Now, let's calculate the percentage of nitrogen in ammonium nitrate:-----------------------------------------------------------||________________________________Now, let's write the formula for ammonium phosphate:-----------------------------------------||______________________First, let's add up the total molar mass of ammonium phosphate below:-----------------------------------------------------------||________________________________Now, let's calculate the percentage of nitrogen in ammonium phosphate:-----------------------------------------------------------||________________________________Which contains a greater percentage of nitrogen by mass?
The nitrogen in ammonium nitrate contains a greater percentage of nitrogen by mass
Explanations:The formula for ammonium nitrate is given as NH4NO3.
Determine the molar mass of NH4NO3
Molar mass = 14 + 4(1) + 14 + 3(16)
Molar mass .= 14 + 4 + 14 + 48
Molar mass of NH4NO3 = 80g/mol
Determine the percentage of nitrogen in the compound
%N = 28/80 * 100
%N = 35%
The formula for ammonium phosphate is (NH4)3PO4
Determine the molar mass of (NH4)3PO4
Molar mass = 3(14) + 4(3) + 4(16) + 3(31)
Molar mass = 42 + 12 + 64 + 31
Molar 1ass = 149g/mol
Determine the percentage of nitrogen in ammonium phosphate:
%N = 42/149 * 100
%N = 28.18%
Hence the nitrogen in ammonium nitrate contains a greater percentage of nitrogen by mass
Complete the second column of the table.Express your answer using two significant figures.
Avogadro's Law is
[tex]\frac{V_1}{n_1}=\frac{V_2}{n_2}[/tex]In the second column of the table, we have to find n1 when V1 = 51 mL, V2 = 13 mL, and n2 = 2.68x10^-4 mol. Solve the equation for n1.
[tex]\begin{gathered} n_1=\frac{V_1\cdot n_2^{}}{V_2}=\frac{51mL\cdot2.68\times10^{-4}mol}{13mL} \\ n_1=11\times10^{-4}mol \\ n_1=0.0011mol \end{gathered}[/tex]Therefore, the number of moles of n1 is 0.0011 moles.
How many moles of sulfur dioxide in 85 grams sulfur dioxide?
Answer:
1.33 moles
Explanation:
[tex]n = \frac{mass}{molar \: mass} [/tex]
note Molar Mass according to websearch is 64 066
you could calculate this using the individual elements on a periodic table (sulfur and oxygen) and their masses
[tex]n = \frac{85}{64.066} [/tex]
[tex]n = 1.33[/tex]
Fe2O3 + 3H2 = 2Fe + 3H2OCalculate how many grams of iron can be made from 24.5 grams of iron (III) oxide.
Explanation:
Iron (III) oxide will react with hydrogen gas to produce iron and water. They will react according to the following equation.
Fe₂O₃ + 3 H₂ -----> 2 Fe + 3 H₂O
We have to find the grams of Fe that can be made from 24.5 g of Fe₂O₃. So, first we have to convert those grams into moles using the molar mass of iron (III) oxide.
molar mass of Fe₂O₃ = 159.69 g/mol
mass of Fe₂O₃ = 24.5 g
moles of Fe₂O₃ = 24.5 g * 1 mol/(159.69 g)
moles of Fe₂O₃ = 0.153 mol
Fe₂O₃ + 3 H₂ -----> 2 Fe + 3 H₂O
According to the coefficients of the equation, we know that 1 mol of Fe₂O₃ will react with 3 moles of H₂ to give 2 moles of Fe and 3 moles of H₂O. So the molar ratio between Fe₂O₃ and Fe is 1 to 2. We can use that relationship to find the number of moles of Fe that can be made from 0.153 moles of Fe₂O₃.
1 mol of Fe₂O₃ : 2 moles of Fe molar ratio
moles of Fe = 0.153 moles of Fe₂O₃ * 2 moles of Fe/(1 mol of Fe₂O₃)
moles of Fe = 0.306 moles
So we found that we can produce 0.306 moles of Fe from 0.153 moles of Fe₂O₃ or 24.5 g of it. Finally we can convert the 0.306 moles of Fe into grams using the molar mass of Fe.
molar mass of Fe = 55.85 g/mol
mass of Fe = 0.306 moles * 55.85 g/mol
mass of Fe = 17.1 g
Answer: 17.1 g of iron can be made from 24.5 g of iron (III) oxide.
Please help me with this question.
Answer:1=B
2=A
Explanation:
using a graduated cylinder and a becker write the detailed steps to measure the volume of a piece of rock
The detailed steps to measure the volume of a piece of rock using a graduated cylinder and beaker are based on Archimedes' Principle, which states that an object that is displacing fluid has a weight equal to that of the object it is displacing.
Step 1: In order to calculate a stone's volume, we first add water to the graduated cylinder until the stone is fully submerged. Step 2: Following the insertion of the stone into the cylinder, the initial reading, or baseline reading, must now be recorded. Step 3: The last reading of the cylinder needs to be recorded after the stone has been fully immersed. Step 4: We can calculate the stone's millilitre capacity by comparing the cylinder's results. If necessary, this value can be changed to another unit of measurement.The submersion or dunking method is another name for the displacement method.
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What is the percent mass of 42.5 g KCl dissolved in 122.5 g water?
Answer
% mass of KCl = 25.76%
Explanation
Given:
mass of KCl = 42.5 g
mass of water = 122.5 g
Required: The % mass of KCl
Solution:
Step 1: Calculate the total mass
42.5 g + 122.5 g = 165 g
Step 2: Calculate the % of KCl
%KCl = (42.5/165)*100
%KCl = 25.76%
when the solute particles mixed with water what do they become
Answer:
the water becomes solvent, and the mixture becomes the solution.
Explanation:
Answer:
a solution
Explanation:
solute and solvent(water) put together would produce a solution
_Ca +_AlCl3 --> _CaCl2 + _AIWhen the reaction is balanced, what is the coefficient in front of the Al? Answer options 2, 4, 1, 3
To balance the given equation remember to start by the elements that are different from oxygen and hydrogen, in this case, let's start by chlorine:
As chlorine in AlCl3 is 3 times and in CaCl2 is 2 times, we have to write a 2 in AlCl3 and a 3 in CaCl2, with this coefficients we will have 6 chlorines in total at each side of the equation.
Then, as we put that 2 in front of AlCl3, we will also have 2 aluminium. After the reaction we have only one aluminium, it means that we need to write 2 in front of Al to balance the number of aluminium in the equation.
The correct option is 2.
Sodium hydroxide is extremely soluble in water. At a certain temperature, a saturated solution contains 573 g NaOH(s) per liter of solution. Calculate the molarity of this saturated NaOH(aq) solution.Concentration: ____________ M
Remember: solution = NaOH + water
Volumen here = 1 L
Molecular mass NaOH = 39.99 g/mol
[tex]M\text{ = }\frac{573\text{ g}}{39.99\text{ }\frac{g}{\text{mol}}x\text{ 1 L}}=\text{ 14.32 }\frac{mol}{L}[/tex]Answer: Contration = 14.32 M
Calculate the percent nitrogen in NH4NO3.Group of answer choices17.5%8%60%28%35%
In order to find the percent composition for Nitrogen in NH4NO3, we will need to work with all the masses from this compound, so let's list them below:
NH4NO3 = 80.04 g/mol
N = 14 grams, but we have 2 nitrogens, therefore = 28 grams
H = 1 gram, 4 Hydrogens = 4 grams
O = 16 grams, 3 Oxygens = 48 grams
Now we take the total mass of the compound as 100% and check how much it will be made by Nitrogen:
80.04 g = 100%
28 g = x %
x = 34.98%, which we can round up to 35% therefore the answer will be letter E
A chemical reaction has the equation 2AgNO3 (aq) + Zn (s) → 2Ag (s) + Zn(NO3)2 (aq). What type of reaction occurs between AgNO3 and Zn?Question 17 options:A) Single displacementB) DecompositionC) SynthesisD) Double displacement
Combination (also called synthesis): Where two elements or one compound and one element will bond and form a new compound as a product, the representation for this reaction is:
A + B -> AB
Decomposition: The opposite from Combination, now one compound will decompose and form 2 new elements or compounds as the product:
AB -> A + B
Single Replacement: One element will take the place of another element in already existing compound:
A + BC -> AB + C
Double Replacement: Now we have two compounds switching elements and forming two new compounds:
AB + CD -> AC + BD
Combustion: Reactions that involve oxygen as reactant and we have CO2 and H2O as products:
X + O2 -> CO2 + H2O
According to the explanation, what we have in this reaction is a Single Displacement reaction, letter A
Given the following, find the number of grams 0.3672 moles SmO
Answer:
61.09 grams SmO
Explanation:
To find the number of grams SmO, you need to multiply the moles by the molar mass of SmO. The molar mass is a ratio which represents the mass of SmO per every 1 mole. It is important to arrange the ratio in a way that allows for the cancellation of units (moles should be in the denominator). The final answer should have 4 sig figs like the given value (0.3672 = 4 sig figs).
Atomic Mass (Sm): 150.36 g/mol
Atomic Mass (O): 15.999 g/mol
Molar Mass (SmO): 150.36 g/mol + 15.999 g/mol
Molar Mass (SmO): 166.359 g/mol
0.3672 moles SmO 166.359 grams
-------------------------------- x -------------------------- = 61.09 grams SmO
1 mole
For an aqueous solution with a H+ concentration of 1.0 × 10−12 M, calculate the concentration of OH−.
Taking into account the definition of pH and pOH, the concentration of OH⁻ is 1×10⁻² M.
Definition of pHpH is a measure of acidity or alkalinity that indicates the amount of hydrogen ions present in a solution or substance.
The pH is defined as the negative base 10 logarithm of the activity of hydrogen ions:
pH= - log [H⁺]
Definition of pOHSimilarly, pOH is a measure of hydroxyl ions in a solution and is expressed as the logarithm of the concentration of OH⁻ ions, with the sign changed:
pOH= - log [OH⁻]
Relationship between pH and pOHThe following relationship can be established between pH and pOH:
pOH + pH= 14
Concentration of OH⁻Being [H⁺]=1.0×10⁻¹² M, the pH is calculated as:
pH= - log (1.0×10⁻¹² M)
Solving:
pH= 12
Being pH= 4.85, and considering the relationship between pH and pOH, pOH is calculated as:
pOH + 12= 14
pOH= 14 - 12
pOH= 2
Replacing in the definition of pOH the concentration of OH⁻ ions is obtained:
- log [OH⁻]= 2
Solving
[OH⁻]= 10⁻²
[OH⁻]= 1×10⁻² M
In summary, the [OH⁻] is 1×10⁻² M.
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How many electrons can have the quantum numbers n = 3, l = 2, ml = -2 ?
1
2
5
10
There are only two electrons that could posses the quantum numbers as shown.
What are quantum numbers?We now that it is often common to seek to describe the probability of finding the electrons in the atom. While it is know that the electron is not a given point in the atom. The probability of finding the electron in the atom is given by the help of the quantum numbers that can be used to describe the position of the electron as shown.
In tis case, we have an electron that has the quantum numbers; n = 3, l = 2, ml = -2. This describes an orbital and there are two electrons in a given orbital.
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Water is a polar solvent; gasoline is a non-polar solvent. Which compound will dissolve in gasoline? Check all that apply.
CCl4
NaCl
NaOH
KCl
Answer:
[tex]\blue{\boxed{\red{\sf CCl_4 \: will \: dissolve \: in \: gasoline}}}[/tex]
Explanation:
The simple concept that would be applied is
'Like Dissolves Like.'
According to this, the polar solvent will dissolve the polar solutes and the non-polar solvent will dissolve the non-polar solutes.
classification of given compounds as polar or non-polar,
[tex]\begin{gathered}\boxed{\begin{array}{c|c} \bf Polar & \bf Non-polar \\ \\ \frac{\qquad \qquad}{} & \frac{\qquad \qquad}{} \\ \sf NaCl & \sf CCl_4 \\ \\ \sf NaOH & \sf - \\ \\ \sf KCl & \sf - \end{array}} \\ \end{gathered}[/tex]
Also, the given data says water is a polar solvent while gasoline is a non-polar solvent. From all the information we have, we can conclude that CCl4 is the only compound that will dissolve in gasoline.
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How is percent composition related to alkene stability?
The stability of alkene can be determined by measuring the amount of energy that is associated with the hydrogenation of the molecule.
What is alkene stability?Because those branched alkanes are more stable than their linear isomers (Figure 1), the origins of this stability are unclear. For each branch in an alkane, the measured heat of formation is lower than expected by about 2 kcal mol−1 in comparison to the linear isomer. The fullness structures in which all atoms have complete valence shells are more stable. The structures with the least number of ritual charges are more stable. The structures with a negative charge on the further electronegative atom will be more stable. The three main factors determining the relative stability of alkenes are i) the number of substituents attached to the double-bond carbon atoms, ii) hyperconjugation, and iii) the stereochemistry of the double bond.
So we can conclude that the more electron-donating alkyl groups are the more stable the alkene
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Calculate the wavelength and energy of light that has a frequency of 1.1 * 10^17 Hz
The wavelength and the energy would be 2.72 × 10⁻⁹ meter 6.886 × 10⁻¹⁷ Joules and respectively if the light has s a frequency of 1.1 × 10¹⁷ Hz.
What is Wavelength?It can be understood in terms of the distance between any two similar successive points across any wave.
C = λν
As given in the problem we have to calculate the energy of the light if the frequency of light is 1.1 × 10¹⁷ Hz
The wavelength of the light = 3 × 10⁸ / 1.1 × 10¹⁷
= 2.72 × 10⁻⁹ meter
The energy of the light = h ν
= 6.26 × 10⁻³⁴ × 1.1 × 10¹⁷
= 6.886 × 10⁻¹⁷ Joules
Thus, the wavelength and the energy would be 2.72 × 10⁻⁹ meter 6.886 × 10⁻¹⁷ Joules and respectively if the light has s a frequency of 1.1 × 10¹⁷ Hz.
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need help with this pleaseeeeeeeeeeeeeeWhat trends do you see in the organisms of the ecosystem if youdecrease sunlight A. Increase in energy storage moleculesB. Decrease in H2OC. Decrease in energy storage moleculesD. Increase in CO2
Answer:
Explanations:
Answer:
Explanations:
Place these Types of Decay in Order from the LOWEST Energy to the HIGHEST energy.
Answer:
[tex]\begin{gathered} Alpha\text{ Decay} \\ Beta\text{ Decay} \\ Gamma\text{ Decay} \end{gathered}[/tex]Explanation:
Here, we want to order the radiations in terms of energy
There is a proportional relationship between the mass and the energy
It is established that the radiation with a higher mass would have the lesser energy
Alpha decay has the highest mass and thus, the lowest energy. This is followed by beta decay, and finally, gamma decay
An intravenous a solution to replace potassium loss contains 35mEq/L each of K+and CL- . How many moles of CL- are in 1.8 L of the solution
The moles of Cl⁻ ions present in 1.8 L of the intravenous solution is 0.063 moles.
What are the moles of Cl⁻ ions in the intravenous solution?The moles of Cl⁻ ions in the intravenous solution are calculated using the conversion factor between mEq/L to mmoles
The conversion between milliequivalents per Liter and millimoles per Liter is:
1 Millimole per Liter = 1 Milliequivalents per Liter.
Hence 35 mEq/L = 35 mmol/L
The mmoles of Cl⁻ ions in 1.8 liters of the intravenous solution will be:
moles of Cl⁻ ions = 35 mmol/L * 1.8 L
moles of Cl⁻ions = 63 mmoles
Converting to moles by dividing by 1000:
moles of Cl⁻ ions = 63 / 1000
moles of Cl⁻ ions = 0.063 moles.
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What is TRUE about the precipitin test?
A.
It determines if blood is type A, B, or O.
B.
It uses hydrogen peroxide to make a chemical reaction.
C.
It requires a very small amount of blood.
D.
It can only be used on blood that is still wet.
Precipitin test is used to determine antigens and human blood from other sources. It is widely used in forensic laboratories. Thus we can determine the blood groups such as A, B,O etc.
What is precipitin?Precipitin is an antibody which precipitates when other antigens binds with it. Thus, antigens from other source can be easily determined using precipitin reaction.
Precipitin reaction involves a specific serological precipitation of an antigen . Varying amounts of the antigen is added to the serum source where each antigen molecule extensively bound to the antibody excess zone.
A small antibody - antigen complex is formed there with crosslinking reaction. The advantages of this test is that very small amount of test sample is needed and about fifty specimens can be easily tested within few minutes.
Therefore, the precipitin test can used to determine the antigen type of blood A, B or O. Hence, option A is correct.
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Answer: A
Explanation:
For each pair of bonds, indicate the more polar bond, and use an arrow to show the direction of polarity in each bond.a. C-O and C-Nb. P-Br and P-Clc. B-O and B-Sd. B-F and B-I
To calculate how polar a bond is we can look at the difference in electronegativity. An electronegativity greater than 1.7 represents an ionic bond, a bond less than 1.7 will be a covalent bond.
Let's see wich is the wich is the electronegativity of each element:
C=2.55
O=3.44
N=3.04
The difference of electronegativity of each pair of bonds will be:
Polar bonds are covalent bonds that have a difference in electronegativities. The greater the difference in electronegativity, the greater the polarity.
So, in this case, C-O bond will be more polar that C-N bond, the polarity.
The direction of the polarity will go towards the more electronegative element. So, we will have:
Answer: The most polar bond will be the C-O bond and the direction of polarity will be toward oxygen for the C-O bond and toward nitrogen for the C-N bond.
Drag each tile to the correct location.
What types of mixtures are these?
peanuts and almonds mixed
food coloring dissolved in water
cup of tea and sugar
together in a bowl
a bucket full of sand and gravel
Homogeneous Mixture
Heterogeneous Mixture
Hetergeneous mixture peanuts and almonds mixed ,a bucket full of sand and gravel. Homogeneous Mixture -food coloring dissolved in water together in a bowl,cup of tea and sugar .
A Heterogeneous Mixture: what is it?When the composition of a mixture is not constant throughout the mixture, the mixture is said to be heterogeneous. A variety of make up vegetable soup. Each mouthful of soup will have variable proportions of the soup's various veggies and other ingredients.
Describe homogenous mixture using an example.For illustration A mixture of sugar and water, or salt and water, both of which have the same component ratio throughout the mixture, are examples of homogenous mixes.
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Express the following in liters at STP: 0.804 moles CCl4
Considering the definition of STP conditions, 4.83 × 10⁻³ moles of HF will occupy a volume of 0.108192 L at STP.
STP conditionsSTP conditions is the abbreviation that refers to standard temperature and pressure. The standard value for pressure is 1 atmosphere and the standard value for temperature is 0°C. They are valid reference values for all gases, and under these conditions 1 mole of any gas occupies an approximate volume of 22.4 liters.
Volume in this caseIn this case, you have 0.804 moles CCl₄. You can apply the following rule of three: if by definition of STP conditions 1 mole of CCl₄ occupies a volume of 22.4 liters, 0.804 moles occupies how much volume?
volume= (0.804 moles ×22.4 L)÷ 1 mole
volume= 18.0096 L
Finally, the volume will be 18.0096 L at STP.
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What is the pH of a solution in which 15 mL of 0.10 M NaOH is added to 25 mL of 0.10 M HCl?
Answer:
The pH of the solution is 1.60.
Explanation:
1st) It is necessary to write and balance the chemical reaction:
[tex]NaOH+HCl\rightarrow NaCl+H_2O[/tex]Now we can see that 1 mole of NaOH reacts with 1 mole of HCl.
2nd) We have to calculate the moles contained in 15mL of 0.10M NaOH solution and the moles contained in 25mL of 0.10M HCl solution:
• Moles contained in NaOH solution:
[tex]\begin{gathered} 1000mL-0.10moles \\ 15mL-x=\frac{15mL*0.10moles}{1000mL} \\ x=1.5*10^{-3}moles \end{gathered}[/tex]• Moles contained in HCl solution:
[tex]\begin{gathered} 1000mL-0.10moles \\ 25mL-x=\frac{25mL*0.10moles}{1000mL} \\ x=2.5x10^{-3}moles \end{gathered}[/tex]Now we know that there are 1.5x10^-3 moles of NaOH and 2.5x10^-3 moles of HCl.
3rd) According to the stoichiometry of the reaction, 1 mole of NaOH reacts with 1 mole of HCl, so in this case, 1.5x10^-3 moles of NaOH will react with 1.5x10^-3 moles of HCl, because NaOH will be the limiting reactant and HCl will be the excess reactant.
So, now we have to calculate the excess of HCl:
2.5x10^-3moles - 1.5x10^-3moles = 1x10^-3moles
Now we know that there are 1x10^-3 moles of HCl left.
4th) Excess HCl will remain dissociated into H+ and Cl-, according to the following equation:
[tex]HCl\rightarrow H^++Cl^-[/tex]That means that for every mole of HCl, 1H+ dissociates. So, in this case, there are 1x10^-3 moles of H+.
Remember that these moles are contained in 40mL, so the molarity of H+ is 0.025M:
[tex]\begin{gathered} 40mL-1x10^{-3}moles \\ 1000mL-x=\frac{1000mL*1x10^{-3}moles}{40mL} \\ x=0.025moles \end{gathered}[/tex]5th) Finally, we can calculate the pH of the solution, by replacing the H+ concentration in the pH formula:
[tex]\begin{gathered} pH=-log\lbrack H^+\rbrack \\ pH=-log\lbrack0.025\rbrack \\ pH=1.60 \end{gathered}[/tex]So, the pH of the solution is 1.60.