Answers
Answer:
8.68
Explanation:
pOH = 8.68
all you need is contained in the sheet
![What Is The POH Of A Solution At 25.0C With [H3O+]=4.8106 M?](https://brainimage.s3.us-east-005.backblazeb2.com/answers/attachments/20CKIlhLZv5XdbYoKXI9Z9ixujUdYfqh.jpeg)
Answer:
Approximately [tex]8.68[/tex].
Explanation:
The [tex]\rm pOH[/tex] of a solution can be found from the hydroxide ion concentration [tex]\rm \left[OH^{-}\right][/tex] with the following equation:
[tex]\displaystyle \rm pOH = -\log_{10} \rm \left[OH^{-}\right][/tex].
On the other hand, the ion-product constant of water, [tex]K_{\text{w}}[/tex], relates the hydroxide ion concentration [tex]\rm \left[OH^{-}\right][/tex] of a solution to its hydronium ion concentration [tex]\rm \left[{H_3O}^{+}\right][/tex]:
[tex]K_\text{w} = \rm \left[{H_3O}^{+}\right] \cdot \rm \left[OH^{-}\right][/tex].
At [tex]25 \; ^\circ \rm C[/tex], [tex]K_{\text{w}} \approx 1.0 \times 10^{-14}[/tex]. For this particular [tex]25 \; ^\circ \rm C[/tex] solution, [tex]\rm \left[{H_3O}^{+}\right] = 4.8 \times 10^{-6}\; \rm mol \cdot L^{-1}[/tex].Hence the [tex]\rm \left[OH^{-}\right][/tex] of this solution:
[tex]\begin{aligned}\left[\mathrm{OH}^{-}\right] &= \frac{K_\text{w}}{\rm \left[{H_3O}^{+}\right]} \\ &= \frac{1.0 \times 10^{-14}}{4.8 \times 10^{-6}}\; \rm mol\cdot L^{-1} \approx 2.08333 \times 10^{-9}\; \rm mol\cdot L^{-1}\end{aligned}[/tex].
Therefore, the [tex]\rm pOH[/tex] of this solution would be:
[tex]\begin{aligned}\rm pOH &= -\log_{10} \rm \left[OH^{-}\right] \\ &\approx -\log_{10} \left(4.8 \times 10^{-6}\right) \approx 8.68\end{aligned}[/tex].
Note that by convention, the number of decimal places in [tex]\rm pOH[/tex] should be the same as the number of significant figures in [tex]\rm \left[OH^{-}\right][/tex].
For example, because the [tex]\rm \left[{H_3O}^{+}\right][/tex] from the question has two significant figures, the [tex]\rm \left[OH^{-}\right][/tex] here also has two significant figures. As a result, the [tex]\rm pOH[/tex] in the result should have two decimal places.
Related Questions
Calculate the moles of Iron (Fe) in 3.8 x 10^{21} atoms of Iron. Please show your work
Answers
Answer: 6.31×10⁻³ moles Fe
Explanation:
To calculate moles when given atoms, we need to use Avogadro's number.
Avogadro's number: 6.022×10²³ atoms/mol
[tex](3.8*10^2^1 atoms)*\frac{mol}{6.022*10^2^3 atoms} =6.31*10^-^3 mols[/tex]
The atoms cancel out, and we are left with moles. There are 6.31×10⁻³ moles Fe.
Which of the following is a salt that will form from the combination of a strong base with a weak acid?
Select the correct answer below:
A. NaHCO3
B. H2O
C. CH3CO2H
D. NH4Cl
Answers
Answer:
A. NaHCO₃
Explanation:
NaHCO₃ ⇒ NaOH + H₂CO₃
NaOH is a strong base and H₂CO₃ is a weak acid. Therefore, NaHCO₃ is a salt of a strong base-weak acid reaction. The salt is basic because carbonic acid (H₂CO₃) is a weak acid so it remains undissociated. So, there is a presence of additional OH⁻ ions that makes the solution basic.
Hope that helps.
Im really confused and select all that apply questions scare me.
Answers
Answer:
The 3rd one
Explanation:
Please Help! Use Hess’s Law to determine the ΔHrxn for: Ca (s) + ½ O2 (g) → CaO (s) Given: Ca (s) + 2 H+ (aq) → Ca2+ (aq) + H2 (g) ΔH = 1925.9 kJ/mol 2 H2 (g) + O2 (g) → 2 H2O (l) ΔH = −571.68 kJ/mole CaO (s) + 2 H+ (aq) → Ca2+ (aq) + H2O (l) ΔH = 2275.2 kJ/mole ΔHrxn =
Answers
Answer:
ΔHrxn = -635.14kJ/mol
Explanation:
We can make algebraic operations of reactions until obtain the desire reaction and, ΔH of the reaction must be operated in the same way to obtain the ΔH of the desire reaction (Hess's law). Using the reactions:
(1)Ca(s) + 2 H+(aq) → Ca2+(aq) + H2(g) ΔH = 1925.9 kJ/mol
(2) 2H2(g) + O2 g) → 2 H2O(l) ΔH = −571.68 kJ/mole
(3) CaO(s) + 2 H+(aq) → Ca2+(aq) + H2O(l) ΔH = 2275.2 kJ/mole
Reaction (1) - (3) produce:
Ca(s) + H2O(l) → H2(g) + CaO(s)
ΔH = 1925.9kJ/mol - 2275.2kJ/mol = -349.3kJ/mol
Now this reaction + 1/2(2):
Ca(s) + ½ O2(g) → CaO(s)
ΔH = -349.3kJ/mol + 1/2 (-571.68kJ/mol)
ΔHrxn = -635.14kJ/molMatch each compound with its appropriate pKa value.
(a) 4-Nitrobenzoic acid, benzoic acid, 4-chlorobenzoic acid pKa=4.19,3.98, and 3.41pKa =4.19,3.98, and 3.41
(b) Benzoic acid, cyclohexanol, phenol pKa=18.0,9.95, and 4.19pK a =18.0,9.95, and 4.19
(c) 4-Nitrobenzoic acid, 4-nitrophenol, 4-nitrophenylacetic acid pKa=7.15,3.85, and 3.41pK a =7.15,3.85, and 3.41
Answers
Answer:
Explanation:
a) 4-nitrobenzoic acid pKa= 3.41
benzoic acid pKa= 4.19
4-chlorobenzoic acid pKa= 3.98
b) benzoic acid pKa= 4.19
cyclohexanol pKa= 18.0
phenol pKa= 9.95
c) 4-Nitrobenzoic acid pKa= 3.41
4-nitrophenol pKa= 7.15
4-nitrophenylacetic acid pKa= 3.85
Consider this synthesis of isoamyl acetate based on this week's experimental methods, after refluxing the reaction mixture for 25 minutes, what is likely present in solution
Answers
Answer:
acetic acid and phosphoric acid
Explanation:
After refluxing the reaction mixture ( synthesis of isoamyl acetate ) what is likely present in the solution is acetic acid and phosphoric acid, this due to the fact that if the reaction time between the reactants was less than the refluxing time which is 25 minutes,
there will be no reactant ( 3-methylbutanol )left in the reaction mixture
whts the ph of po4 9.78
Answers
Answer:
4.22
Explanation:
We know from the question, that the pOH of the solution is 9.78. Now the pOH is defined as -log [OH^-].
If the pOH of a solution is given, one may obtain the pH of such solution from the formula;
pH + pOH =14
Hence we can write;
pH = 14-pOH
pH = 14 - 9.78 = 4.22
Hence the pH of the solution is 4.22.
A chemist fills a reaction vessel with 0.978 g aluminum hydroxide AlOH3 solid, 0.607 M aluminum Al+3 aqueous solution, and 0.396 M hydroxide OH− aqueous solution at a temperature of 25.0°C.
Under these conditions, calculate the reaction free energy ΔG for the following chemical reaction:
Al(OH)3(s) = A1+ (aq) +30H (aq)
Use the thermodynamic information in the ALEKS Data tab. Round your answer to the nearest kilojoule.
KJ
Answers
Answer: [tex]\Delta G^{0}[/tex] = 168.12 kJ
Explanation: Gibbs Free Energy, at any time, is defined as the enthalpy of the system minus product of temperature and entropy of the reaction, i.e.:
[tex]\Delta G^{0} = \Delta H^{0} - T.\Delta S^{0}[/tex]
Enthalpy is defined as internal heat existent in the system. It is calculated as:
[tex]\Delta H^{0} = \Sigma H^{0}_{product} - \Sigma H^{0}_{reagent}[/tex]
Using Enthalpy Formation Table:
[tex]\Delta H^{0} = [3*(-299.9)+(-524.7)] - (-1277)[/tex]
[tex]\Delta H^{0} = 62,6 kJ[/tex]
Entropy is the degree of disorder in the system. It is found by:
[tex]\Delta S^{0} = \Sigma S^{0}_{products} - \Sigma S^{0}_{reagents}[/tex]
Calculating:
[tex]\Delta S^{0} = (-321.7) + 3(-10.8) - 0[/tex]
[tex]\Delta S^{0} = -354.1J[/tex]
And so, Gibbs Free energy will be:
[tex]\Delta G^{0} = \Delta H^{0} - T.\Delta S^{0}[/tex]
[tex]\Delta G^{0} = 62600 - [298.(-354.1)][/tex]
[tex]\Delta G^{0} = 168121.8 J[/tex]
Rounding to the nearest kJ:
[tex]\Delta G^{0}[/tex] = 168.12 kJ
During a titration, a known concentration of _____ is added to a _____ of an unknown concentration g
Answers
Explanation:
The whole process of titration involves finding the concentration of a solution (usually an acid or base) by adding (titrating) it to a solution(acid or base) with a known concentration.
The solution of unknown concentration (the analyte) is usually placed in an flask, while the solution of known concentration (titrant) is placed in a burette and slowly added to the flask.
20. What volume of 0.350M KMnO4 solution must be diluted to prepare 600. mL of
0.150M KMnO4 solution?
Answers
Answer:
25.7 mL
Explanation:
Step 1: Given data
Initial volume (V₁): ?Initial concentration (C₁): 0.350 MFinal volume (V₂): 600 mLFinal concentration (C₂): 0.150 MStep 2: Calculate the volume of the initial solution
We have a concentrated solution and we want to prepare a diluted one. We can calculate the initial volume using the dilution rule.
C₁ × V₁ = C₂ × V₂
V₁ = C₂ × V₂ / C₁
V₁ = 0.150 M × 600 mL / 0.350 M
V₁ = 25.7 mL
13. If atoms from two different elements react to form a compound, the element with a higher
number
will have a negative oxidation
A. atomic radius
B. energy
C. electronegativity
D. atomic number
Answers
Answer:
C. electronegativity
Explanation:
THE ELEMENT WITH THE GREATE ELECTRONEGATIVITY IS ASSIGNED A NEGATIVE OXIDATION NUMBER EQUAL TIO ITS CHARGE
A chemist prepares a solution of sodium nitrate by measuring out of sodium nitrate into a volumetric flask and filling the flask to the mark with water.
Calculate the concentration in mol/L of the chemist's sodium nitrate solution. Round your answer to 3 significant digits.
Answers
Answer:
5.74M or 5.74 mol/L (to 3 sign. fig.)
Explanation:
The molar mass of NaNO3 is 85g/mol, which means that:
1 mole of NaNO3 - 85g
? moles - 122.0g
= 122/85 = 1.44 moles
Concentration in mol/L = no. of moles (moles) ÷ volume (L)
[tex]\frac{1.44}{0.250}[/tex] = 5.74M or 5.74 mol/L (to 3 sign. fig.)
I hope the steps are clear and easy to follow.
By December 31, 2003, concerns over arsenic contamination had prompted the manufacturers of pressure-treated lumber to voluntarily cease producing lumber treated with CCA (chromated copper arsenate) for residential use. CCA-treated lumber has a light greenish color and was widely used to build decks, sand boxes, and playground structures.
Required:
Draw the Lewis structure of the arsenate ion (ASO4^3-) that yields the most favorable formal charges.
Answers
Answer:
Explanation:
lewis structure can be defined as a process of how the valence shell electrons of a molecule is being arranged, the pattern of it arrangement and the relationship between the bonding atoms and the lone pairs present in the molecule.
In order to draw the Lewis structure for Arsenate ion [tex]\mathsf{AsO \ _4^{3-}}[/tex], first thing is to count the valence electrons in the molecule. Once we determine the valence electrons, then we distribute them around the central atom. The Arsenate ion structure is tetrahedral in nature with a bond angle of 109.5° and it is sp³ hybridized.
If we want to change a gas to its liquid state, should we add or remove energy from the gas?
Answers
Suppose that 13 mol NO2 and 3 mol H2O combine and react completely. How many moles of the reactant in excess are present after the reaction has completed
Answers
Answer:
The number of moles of excess reagent NO₂ that are present after the reaction has completed is 7 moles.
Explanation:
The balanced reaction is:
3 NO₂ + H₂O → 2 HNO₃ + NO
By stoichiometry of the reaction (that is, the relationship between the amount of reagents and products in a chemical reaction), the following amounts of reactants and products participate in the reaction:
NO₂: 3 molesH₂O: 1 moleHNO₃: 2 molesNO: 1 molesThe limiting reagent is one that is consumed in its entirety first, determining the amount of product in the reaction. When the limiting reagent ends, the chemical reaction will stop.
In other words, the limiting reagent is that reagent that is consumed first in a chemical reaction, determining the amount of products obtained. The reaction depends on the limiting reagent, because the other reagents will not react when one is consumed.
You can apply the following rule of three: if by stoichiometry of the reaction 3 moles of NO₂ react with 1 mole of H₂O, 13 moles of NO₂ react with how many moles of H₂O?
[tex]moles of H_{2}O=\frac{13 moles of NO_{2}*1 mole of H_{2}O }{3 moles of NO_{2}}[/tex]
moles of H₂O= 4.33 moles
But 4.33 moles of H₂O are not available, 3 moles are available. Since you have less moles than you need to react with 13 moles of NO₂, water H₂O will be the limiting reagent.
To determine the number of moles of excess reagent NO2 that are present after the reaction is complete, you can apply the following rule of three: if by stoichiometry of the reaction 1 moles of H₂O react with 3 mole of NO₂, 3 moles of H₂O react with how many moles of NO₂?
[tex]moles of NO_{2}=\frac{3 moles of NO_{2}*3 mole of H_{2}O }{1 mole of H_{2}O}[/tex]
moles of NO₂= 6 moles
If 6 moles of NO₂ react and 13 moles of the compound are present, the amount that remains in excess is calculated as: 13 moles - 6 moles= 7 moles
The number of moles of excess reagent NO₂ that are present after the reaction has completed is 7 moles.
Calculate the molarity of bromide ions in 250. mL of a solution containing 25.9 g NaBr and 0.155 moles of HBr.
Answers
Answer:
[tex]1.628 M[/tex]
Explanation:
From the question we were given 0.155 moles of HBr, but Br and H are in ratio 1:1, then there are 0.155 moles of Br- ions.
We were also told that the solution contain NaBr, of 25.9 g. Then it must be converted to moles.
molar mass of NaBr =(22.99g + 79.90 )
= 102.89 g per mol.
the moles of NaBr can be calculated as 25.9 / 102.89
=0.252 moles
But Na and Br are in a ratio 1:1 , then there are 0.252 moles of Br-.
Then to get two Br- mol , we will add the first and second mol of Br- together
= 0.155 + 0.252
=0.407 moles.
The given solution has volume of 250 mL, but we know that there are 1000 ml in a liter, then if we convert to L for unit consistency we have
= 250/1000
= 0.25 L
molarity=0.407 moles/0.25 L
= 1.628 M.
Therefore, Br ion molarity is 1.628 M.
The molarity of the Br ions in the 250 ml solution has been 1.628 M.
Moles can be defined as the mass per unit molecular mass. Moles can be expressed as:
Moles = [tex]\rm \dfrac{weight}{molecular\;weight}[/tex]
Moles of NaBr = [tex]\rm \dfrac{25.9}{102.89}[/tex]
Moles of NaBr = 0.252 mol
Moles of HBr = 0.155 mol.
Since both the compounds have 1:1 ratio of atom: Br, the Br produced has been equal to the concentration of the compound.
Br from NaBr = 0.252 mol
Br from HBr = 0.155 mol.
Total Br ions = 0.407 mol.
Molarity can be expressed as:
Molarity = [tex]\rm moles\;\times\;\dfrac{1000}{Volume\;(ml)}[/tex]
Molarity of Br ions = 0.407 × [tex]\rm \dfrac{1000}{250\;ml}[/tex]
Molarity of Br ions = 1.628 M.
The molarity of the Br ions in the 250 ml solution has been 1.628 M.
For more information about the molarity, refer to the link:
https://brainly.com/question/12127540
The following reaction, catalyzed by iridium, is endothermic at 700 K: CaO(s) + CH4(g) + 2H2O (g) → CaCO3 (s) + 4H2 (g) For the reaction mixture above at equilibrium at 700 K, how would the following changes affect the total quantity of CaCO3 in the reaction mixture once equilibrium is re-established?
a. Increasing the temperature
b. Adding calcium oxide (CaO)
c. Removing methane (CH4)
d. Increasing the total volume
e. Adding iridium
Answers
Answer:
A. Increasing the temperature will favor forward reaction and more CaCo3 formed.
B. More CaCo3 will be formed.
C. CaCo3 will decrease and more react ants formed.
D. Less CaCo3 will be formed.
E. Iridium is a catalyst so there is no effect
Explanation:
A. Temperature will increase because it's an endothermic reaction.
B. Adding Cao will favor forward reaction and more CaCo3 formed.
C. Removing methane, more react ants are formed and CaCo3 decreases.
D. Irridi is a catalyst so it has no effect on the CaCo3 but only speeds its rate of reaction.
A 0.753 g sample of a monoprotic acid is dissolved in water and titrated with 0.250 M NaOH. What is the molar mass of the acid if 21.5 mL of the NaOH solution is required to neutralize the sample?
Answers
Answer:
[tex]MM_{acid}=140.1g/mol[/tex]
Explanation:
Hello,
In this case, since the acid is monoprotic, we can notice a 1:1 molar ratio between, therefore, for the titration at the equivalence point, we have:
[tex]n_{acid}=n_{base} \\\\V_{acid}M_{acid}=V_{base}M_{base}\\\\n_{acid}=V_{base}M_{base}[/tex]
Thus, solving for the moles of the acid, we obtain:
[tex]n_{acid}=0.0215L*0.250\frac{mol}{L}=5.375x10^{-3}mol[/tex]
Then, by using the mass of the acid, we compute its molar mass:
[tex]MM_{acid}=\frac{0.753g}{5.375x10^{-5}mol} \\\\MM_{acid}=140.1g/mol[/tex]
Regards.
Given that H2(g)+F2(g)⟶2HF(g)ΔH∘rxn=−546.6 kJ 2H2(g)+O2(g)⟶2H2O(l)ΔH∘rxn=−571.6 kJ calculate the value of ΔH∘rxn for
Answers
Answer:
ΔH∘rxn of the reaction is -521.6kJ
Explanation:
Complete question: "Calculate the value of ΔH°rxn for 2F2(g)+2H2O(l)⟶4HF(g)+O2(g)"
You can find the ΔH of a reaction by the algebraic sum of similar reactions (Hess's law) as follows:
(1) H₂(g) + F₂(g) ⟶ 2HF(g) ΔH∘rxn=−546.6 kJ
(2) 2H₂(g)+O₂(g)⟶2H₂O(l) ΔH∘rxn=−571.6 kJ
Subtracting 2ₓ(1) - (2)
2ₓ(1) 2H₂(g) + 2F₂(g) ⟶ 4HF(g) ΔH∘rxn=2ₓ−546.6 kJ = -1093.2kJ
-(2) 2H₂O(l) ⟶ 2H₂(g)+O₂(g) ΔH∘rxn=- (-571.6 kJ) = 571.6kJ
2ₓ(1) - (2) 2F₂(g)+ 2H₂O(l) ⟶ 4HF(g) + O₂(g)
H₂(g) are cancelled because are the same in products and reactants
ΔH∘rxn = -1093.2kJ + 571.6kJ
ΔH∘rxn = -521.6
ΔH∘rxn of the reaction is -521.6kJg Which ONE of the following pairs of organic compounds are NOT pairs of isomers? A) butanol ( CH3-CH2-CH2-CH2-OH ) and diethyl ether ( CH3–CH2–O–CH2–CH3 ) B) isopentane ( (CH3)2-CH-CH2-CH3 ) and neopentane ( (CH3)4C ) C) ethanolamine ( H2N-CH2-CH2-OH ) and acetamide ( CH3-CO-NH2 ) D) acrylic acid ( CH2=CH-COOH ) and propanedial ( OHC–CH2–CHO ) E) trimethylamine ( (CH3)3N ) and propylamine ( CH3-CH2-CH2-NH2 )
Answers
Answer:
ethanolamine ( H2N-CH2-CH2-OH ) and acetamide ( CH3-CO-NH2 )
Explanation:
Isomers are compounds that have the same molecular formula but different structural formulas. Hence any pair of compounds that can be represented by exactly the same molecular formula are isomers of each other.
If we look at the pair of compounds; ethanolamine ( H2N-CH2-CH2-OH ) and acetamide ( CH3-CO-NH2 ), one compound has molecular formula, C2H7ON while the other has a molecular formula, C2H5ON, hence they are not isomers of each other.
An aqueous solution of potassium bromide, KBr, contains 4.34 grams of potassium bromide and 17.4 grams of water. The percentage by mass of potassium bromide in the solution is 20 %.
Answers
Answer:
True
Explanation:
The percentage by mass of a substance in a solution can be calculated by dividing the mass of the substance dissolved in the solution by the total mass of the solution. This can be expressed mathematically as:
Percentage by mass = mass of substance in solution/mass of solution x 100
In this case;
mass of KBr = 4.34 grams
mass of water = 17.4 grams
mass of solution = mass of KBr + mass of water = 4.34 + 17.4 = 21.74
Percentage by mass of KBr = 4.34/21.74 x 100
= 19.96 %
19.96 is approximately 20%.
Hence, the statement is true.
When we react a weak acid with a strong base of equal amounts and concentration, the component of the reaction that will have the greatest effect on the pH of the solution is:______.
a. the acid.
b. the base.
c. the conjugate acid.
d. the conjugate base.
Answers
Answer:
d. the conjugate base.
Explanation:
The general reaction of a weak acid, HA, with a strong base YOH, is:
HA + YOH → A⁻ + H₂O + Y⁻
Where A⁻ is the conjugate base of the weak acid and Y⁻ usually is a strong electrolyte.
That means after he complete reaction you don't have weak acid nor strong base, just conjugate base that will be in equilibrium with water, thus (Strong electrolyte doesn't change pH:
A⁻ + H₂O ⇄ HA + OH⁻
As the equilibrium is producing OH⁻, the pH of the solution is being affected for the conjugate base
Right option:
d. the conjugate base.Al diluir 25 g de sal de mesa en 250ml de agua, ¿En cuántos °C aumenta el punto de ebullición de la disolución formada? ( Ke = 0,52 °C/molal , PM NaCl = 58,44 g/mol)
Answers
Answer:
ΔT=[tex]0.87^{\circ}C[/tex]
Explanation:
Para esta pregunta debemos recordar la ecuación que nos permite calcular el aumento ebulliscopico (aumento del punto de ebullición):
ΔT=[tex]Kb*m[/tex]
Donde ΔT es el valor del aumento del punto de ebullición. Kb es la constante ebulloscopica para el agua ([tex]0.512\frac{Kg~^{\circ}C}{mol}[/tex]) y m es la molalidad ([tex]m=\frac{mol}{Kg~ of~ solvente}[/tex]).
Por lo tanto el primer paso es calcular la molalidad de la solución. Para lo cual tendremos que calcular las moles de sal en los 25 g. Si queremos hacer esto debemos recordar que la formula de sal de mesa es NaCl y que la masa molar de NaCl es 58.44 g/mol. Por lo tanto:
[tex]25~g~NaCl\frac{1~mol~NaCl}{58.44~g~NaCl}~=~0.42~mol~NaCl[/tex]
Ahora bien, también debemos saber los Kg de agua en la solución. Por lo que podemos usar la densidad del agua (1 g/mL) para convertir de mL a g y luego hacer la conversión a Kg:
[tex]250~mL\frac{1~g}{1~mL}\frac{1~Kg}{1000~g}~=~0.25~Kg[/tex]
Finalmente para el calculo de la molalidad podemos dividir los dos valores:
[tex]m=\frac{0.42~mol}{0.25~Kg}=1.68[/tex]
Con el valor de la molalidad se puede calcular ΔT al reemplazar los valores:
ΔT=[tex]1.68~\frac{mol}{Kg}*0.52\frac{Kg~^{\circ}C}{mol}=0.87^{\circ}C[/tex]
Si la temperatura de ebullición normal del agua es 100 ºC. Podemos calcular la temperatura final si adicionamos ΔT:
Temperatura final = 100 + 0.87 = 100.87 ºC
Espero sea de ayuda!
From the following balanced equation, CH4(g)+2O2(g)⟶CO2(g)+2H2O(g) how many grams of H2O can be formed when 1.25g CH4 are combined with 1.25×10^23 molecules O2? Use 6.022×10^23 mol−1 for Avogadro's number.
Answers
Answer:
2.81 g of H2O.
Explanation:
We'll begin by calculating mass of O2 that contains 1.25×10²³ molecules O2.
This can be obtained as follow:
From Avogadro's hypothesis, we understood that 1 mole of any substance contains 6.022×10²³ molecules. This implies that 1 mole of O2 also contains 6.022×10²³ molecules.
1 mole of O2 = 16x2 = 32 g.
Thus 6.022×10²³ molecules is present in 32 g of O2,
Therefore, 1.25×10²³ molecules will be present in =
(1.25×10²³ × 32) / 6.022×10²³ = 6.64 g of O2.
Therefore, 1.25×10²³ molecules present in 6.64 g of O2.
Next, the balanced equation for the reaction. This is given below:
CH4(g) + 2O2(g) —> CO2(g) + 2H2O(g)
Next, we shall determine the masses of CH4 and O2 that reacted and the mass of H2O produced from the balanced equation.
This can be obtained as follow:
Molar mass of CH4 = 12 + (4x1) = 16 g/mol.
Mass of CH4 from the balanced equation = 1 x 16 = 16 g
Molar mass of O2 = 16x2 = 32 g/mol.
Mass of O2 from the balanced equation = 2 x 32 = 64 g
Molar mass of H2O = (2x1) + 16 = 18 g/mol.
Mass of H2O from the balanced equation = 2 x 18 = 36 g
From the balanced equation above,
16 g of CH4 reacted with 64 g of O2 to produce 36 g if H2O.
Next, we shall determine the limiting reactant.
This can be obtained as follow:
From the balanced equation above,
16 g of CH4 reacted with 64 g of O2.
Therefore, 1.25 g of CH4 will react with = (1.25 x 64)/16 = 5 g of O2.
From the above calculations, we can see that only 5 g out of 6.64 g of O2 is needed to react completely with 1.25 g of CH4.
Therefore, CH4 is the limiting reactant.
Finally, we shall determine the mass of H2O produced from the reaction.
In this case, the limiting reactant will be used because it will give the maximum yield of H2O.
The limiting reactant is CH4 and the mass of H2O produced from the reaction can be obtained as follow:
From the balanced equation above,
16 g of CH4 reacted to produce produce 36 g if H2O.
Therefore, 1.25 g of CH4 will react to produce = (1.25 x 36)/16 = 2.81 g of H2O.
Therefore, 2.81 g of H2O were obtained from the reaction.
The mass in grams of H₂O which can be formed when 1.25g CH₄ are combined with 1.25×10²³ molecules O₂ is 2.8 grams.
What is stoichiometry?Stoichiometry of any reaction tells about the amount of species present before and after the completion of the reaction.
Given chemical reaction is:
CH₄(g) + 2O₂(g) → CO₂(g) + 2H₂O(g)
Moles of CH₄ will b calculate as:
n = W/M, where
W = given mass = 1.25g
M = molar mass = 16g/mol
n = 1.25/16 = 0.078 moles
Molecues of CH₄ in 0.078 moles = 0.078×6.022×10²³ = 0.46×10²³
Given molecules of O₂ = 1.25×10²³
Required molecules of CH₄ is less as compared to the molecules of O₂, so here CH₄ is the limiting reagent and formation of water is depends on it only.
From the stoichiometry of the reaction it is clear that:
1 mole of CH₄ = will produce 2 moles of H₂O
0.078 moles of CH₄ = will produce 2×0.078=0.156 moles of H₂O
Mass of H₂O will be calculated by using its moles as:
W = (0.156)(18) = 2.8g
Hence required mass of H₂O is 2.8g.
To know more about limiting reagent, visit the below link:
https://brainly.com/question/1163339
Emission of which one of the following leaves both atomic number and mass number unchanged?
(a) positron
(b) neutron
(c) alpha particle
(d) gamma radiation
(e) beta particle
Answers
Answer: Gamma Radiation
Explanation:
The emission of Gamma rays does not cause a change in both the atomic and mass number. They are electromagnetic radiation.
The radiations that leaves without changing the atomic mass and atomic number of the particle have been gamma radiations. Thus, option D is correct.
Radiations have been the energy that has been evolved by the particles during energy transitions. The nuclear decay results with the release of the energy from the particle resulting in the change in the atomic mass.
The electromagnetic radiations have been capable of emitting the radiation without changing the mass and atomic number of the element. The gamma radiations have been the electromagnetic radiations. Thus, option D is correct.
For more information about the emissions, refer to the link:
https://brainly.com/question/517329
Sighting along the C2-C3 bond of 2-methylbutane, the least stable conformation (Newman projection) has a total energy strain of ______kJ/mol
Answers
Answer:
21 KJ/mol
Explanation:
For this question, we have to start with the linear structure of 2-methylbutane. With the linear structure, we can start to propose all the Newman projections keep it in mind that the point of view is between carbons 2 and 3 (see figure 1).
Additionally, we have several energy values for each interaction present in the Newman structures:
-) Methyl-methyl gauche: 3.8 KJ/mol
-) Methyl-H eclipse: 6.0 KJ/mol
-) Methyl-methyl eclipse: 11.0 KJ/mol
-) H-H eclipse: 4.0 KJ/mol
Now, we can calculate the energy for each molecule.
Molecule A
In this molecule, we have 2 Methyl-methyl gauche interactions only, so:
(3.8x2) = 7.6 KJ/mol
Molecule B
In this molecule, we have a Methyl-methyl eclipse interaction a Methyl-H eclipse interaction and an H-H eclipse interaction, so:
(11)+(6)+(4) = 21 KJ/mol
Molecule C
In this molecule, we have 1 Methyl-methyl gauche interaction only, so:
3.8 KJ/mol
Molecule D
In this molecule, we have three Methyl-H eclipse interaction, so:
(6*3) = 18 KJ/mol
Molecule E
In this molecule, we have 1 Methyl-methyl gauche interaction only, so:
3.8 KJ/mol
Molecule F
In this molecule, we have a Methyl-methyl eclipse interaction a Methyl-H eclipse interaction and an H-H eclipse interaction, so:
(11)+(6)+(4) = 21 KJ/mol
The structures with higher energies would be less stable. In this case, structures B and F with an energy value of 21 KJ/mol (see figure 2).
I hope it helps!
1. Why is it not possible to resolve the compound CH3-NH-CH2-CH3 into a pair of enantiomers?
2. Which one of the following is not affected (or is least affected) by the lone pair of electrons on an amine's nitrogen?
a. solubility in alcohols and in water.
b. hydrogen-bond formation.
c. melting point.
d. dipole moment.
e. basicity.
3. Which of the following compounds is most basic?
a. cyclohexyl amine.
b. p-nitroaniline.
c. 2,6-dimethylaniline.
d. p-methoxyaniline.
d. aniline.
Answers
Answer:
1. In the compound, H3C-NH-CH2-CH3, there are no chiral centers present, chiral centers refer to the configuration in which carbon is attached with four different groups. In the molecules, as there are no chiral centers, therefore the molecule is optically inactive, that is, it will not demonstrate pair of an enantiomer is one of the essential characteristics of optically active compounds is the possession of enantiomeric pairs.
2. On the nitrogen of aniline, the lone pair of electrons can produce hydrogen bonds, play an essential function in basicity, play an essential role in dipole moment or polarity, and wit the increase in solubility there is an increase in the formation of the hydrogen bond, eventually increasing to boiling point. However, the melting point is not affected. As the melting point is the characteristic of the packing efficacy of a molecule and does not rely upon the anilinic nitrogen's lone pairs.
3. With the increase in the tendency to donate an electron, basicity increases. However, if the electron is taking part in resonance, the donation will not take place easily, and the compound will be the least basic. Apart from cyclohexyl amine, in all the other given compounds, the lone pair of nitrogen takes part in the process of delocalization or conjugation. Thus, cyclohexyl amine will be most basic as the lone pairs are easily available for donation.
Zeros laced at the end of the significant number are...
Answers
Answer:
Zeros located at the end of significant figures are significant.
Explanation:
Hope it will help :)
What attractive force holds two hydrogen atoms and one oxygen atom
together to make the substance water?
A. Molecules
B. Chemical bonding
O C. Valence electrons
O D. Cations
Answers
Answer:
It is a hydrogen bond but if I had to coose one of thee answers it is b. chemical bonding
Explanation:
15.Vicinal coupling is:A)coupling between 1H nuclei attached to adjacent C atoms.B)coupling between 1H nuclei in an alkene.C)coupling between 1H nuclei attached to the same C atom.D)coupling between 1H nuclei in an alkane.
Answers
Answer:
A)coupling between 1H nuclei attached to adjacent C atoms.
Explanation:
The word ‘vicinal’ in chemistry means three bonds from the functional groups. The two functional groups are in a relationship with the atoms in adjacent position to them.
The 1H nuclei consists of two Hydrogen nucleus which acts as the functional groups. They are however attached and in a relationship with the adjacent C atoms. This makes option A the right choice.
