Answer:
When the two gases are mixed, the ammonium chloride precipitates in the tube walls.
Explanation:
This is the reaction:
HCl (g) + NH₃(g) → NH₄Cl (s) ↓
As the product formed is solid at room temperature, a suspension is first formed in the internal air of the tube that appears as a cloud. Afterwards it finally precipitates into the walls forming a white layer
Given the number of valence electrons in neutral atoms, predict the charge of the ions each will form.
one valence electron
two valence electrons
six valence electrons
seven valence electrons
eight valence electrons
a. generally does not form ions
b. forms ion with 2- charge
c. forms ion with 2+ charge
d.forms ion with 1+ charge
e. forms ion with 1- charge
The charges of the ions of the given valency electrons are as follows;
one valence electron → +1
two valence electrons → +2
six valence electrons → -2
seven valence electrons → -1
eight valence electrons → does not form ion.
The valency electron of a neutral atom determines the charge it possess
when it forms an ion. They may form cations or anions or even possess no
charge.
A neutral atom with one valency electron will form +1 charge.
A neutral atom with two valency electron will form +2 charge.
A neutral atom with six valency electron will form -2 charge.
A neutral atom with seven valency electron will form -1 charge.
A neutral atom with eight valency electron will not form any ions.
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In Experiment #6 you learned that Zn will dissolve in acidic aqueous solutions as Zn2+, but Cu will not dissolve because Cu is less active than H2. A stronger oxidizing agent than H+ is required to oxidize Cu. Aqueous solutions of ________________ are strong oxidizing agents that are capable of oxidizing a number of less active metals, including Cu.
Answer:family fdhdfgfdsh
Nitric acid aqueous solutions are strong oxidizing agents capable of oxidizing a variety of less active metals, including Cu.
What is Nitric acid?The inorganic compound nitric acid has the formula HNO3. It is a mineral acid that is extremely corrosive. The compound is colorless, but older samples have a yellow cast due to decomposition into nitrogen oxides. The majority of commercially available nitric acid has a water concentration of 68%. Nitric acid is used to make ammonium nitrate, a key component of fertilizers. It is also used to make explosives such as nitroglycerin and trinitrotoluene (TNT), as well as to oxidize metals. Nitric acid, with the chemical formula HNO3, is a strong acid. It is also known as niter's spirit and aqua fortis. It is colorless in its pure form, but as it ages, it takes on a yellow cast.
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What is the atomic number of pt-175 after it undergoes alpha decay
Answer:
76
Explanation:
Alpha decay is one of the most basic forms of radioactive decay. It has an atomic mass of 4 and a proton number of two.
Undergoing an alpha decay will decrease the atomic mass by four and the atomic number by two.
In this particular question, we are particular about the atomic number. The atom has an atomic number of 78. So taking 2 off this gives 76
The atomic number of pt-175 after it undergoes alpha decay is 76
Radioactive decay is defined as the splitting of heavy unstable isotopes to two or more stable particles. The three main types of radioactive decay are
alpha decay (α-decay).beta decay (β-decay)gamma decay(γ-decay)An Alpha decay occurs when the radioactive nucleus releases a helium ion (alpha particle) leaving the daughter nucleus with a reduced atomic number by 2 and reduced atomic mass by 4.
An example is the alpha decay below
¹⁷⁵Pt₇₈ ----> ¹⁷¹ Os₇₆ + ⁴ He₂
Here,Platinum 175 with atomic number 78 undergoes alpha decay to produce Osmium 171 with atomic number 76.
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Given that H 2 ( g ) + F 2 ( g ) ⟶ 2 HF ( g ) Δ H ∘ rxn = − 546.6 kJ H2(g)+F2(g)⟶2HF(g)ΔHrxn°=−546.6 kJ 2 H 2 ( g ) + O 2 ( g ) ⟶ 2 H 2 O ( l ) Δ H ∘ rxn = − 571.6 kJ 2H2(g)+O2(g)⟶2H2O(l)ΔHrxn°=−571.6 kJ calculate the value of Δ H ∘ rxn ΔHrxn∘ for 2 F 2 ( g ) + 2 H 2 O ( l ) ⟶ 4 HF ( g ) + O 2 ( g )
Answer:
ΔH° = -521,6kJ
Explanation:
It is possible to obtain the ΔH° of a reaction using Hess's law that consist in the algebraic sum of the ΔH° of semireactions.
For the semireactions:
(1) H₂(g) + F₂(g) ⟶ 2HF(g) ΔHrxn° = −546.6kJ
(2) 2H₂(g) + O₂(g) ⟶ 2H₂O(l) Δ Hrxn° = −571.6kJ
The sum of 2×(1) - (2) gives:
2F₂(g) + 2H₂O(l) ⟶ 4HF(g) + O₂(g)
The ΔH° for this reaction is:
ΔH° = -546,6kJ×2 - (-571,6kJ)
ΔH° = -521,6kJ
I hope it helps!
ΔHrxn ° for 2 F₂ (g) + 2 H₂O (l) ⟶ 4HF (g) + O₂ (g): -521.6 kJ
Further explanationThe change in enthalpy in the formation of 1 mole of the elements is called enthalpy of formation
The enthalpy of formation measured in standard conditions (25 ° C, 1 atm) is called the standard enthalpy of formation (ΔHf °)
Determination of the enthalpy of formation of a reaction can be through a calorimetric experiment, based on the principle of Hess's Law, enthalpy of formation table, or from bond energy data
Delta H reaction (ΔH) is the amount of heat / heat change between the system and its environment
(ΔH) can be positive (endothermic = requires heat) or negative (exothermic = releasing heat)
The value of ° H ° can be calculated from the change in enthalpy of standard formation:
∆H ° rxn = ∑n ∆Hf ° (product) - ∑n ∆Hf ° (reactants)ΔH∘rxn = ΔH∘f of the product (s) if ∆Hf ° (reactants) = 0
Based on the principle of Hess's Law, the change in enthalpy of a reaction will be the same even though it is through several stages or ways
Known ΔHrxn from reaction:
H₂ (g) + F₂ (g) ⟶2HF (g) ΔHrxn ° = −546.6 kJ reaction 1 (R1)
2H₂ (g) + O₂ (g) ⟶2H₂O (l) ΔHrxn ° = −571.6 kJ reaction 2 (R2)
ΔHrxn from reaction:
2 F₂ (g) + 2 H₂O (l) ⟶ 4HF (g) + O₂ (g) reaction 3 (R3)
Can be searched from ΔHrxn ° R1 and R2
From R3 it is known that the reaction coefficient of F₂ is 2, so we can multiply R1 by 2 (include ΔHrxn °)
2H₂ (g) + 2F₂ (g) ⟶4HF (g) ΔHrxn ° = −1093.2 kJ reaction 4 (R4)
R3 H₂O lies in the reactants, so that we can reverse R2,and so ΔHrxn ° is marked +
2H₂O (l) ⟶2H₂(g) + O₂ (g) ΔHrxn ° = + 571.6 kJ reaction 5 (R5)
We add R4 to R5 to get R3, by removing 2H₂ (g) because it is located in the reactants and products
2H₂ (g) + 2F₂ (g) ⟶4HF (g) ΔHrxn ° = −1093.2 kJ
2H₂O (l) ⟶2H₂ (g) + O₂ (g) ΔHrxn ° = + 571.6 kJ
-------------------------------------------------- -------------------- +
2F₂ (g) + 2H₂O (l) ⟶ 4HF (g) + O₂ (g) ΔHrxn ° = -521.6 kJ
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Delta H solution
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an exothermic reaction
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as endothermic or exothermic
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an exothermic dissolving process
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Naturally occurring element X exists in three isotopic forms: X-28 (27.977 amu, 92.23% abundance), X-29 (28.976 amu, 4.67% abundance), and X-30 (29.974 amu, 3.10% abundance). What is the identity of element X?
Answer:
Silicon
Explanation:
The formula for the calculation of the average atomic mass is:
[tex]Average\ atomic\ mass=(\frac {\%\ of\ the\ first\ isotope}{100}\times {Mass\ of\ the\ first\ isotope})+(\frac {\%\ of\ the\ second\ isotope}{100}\times {Mass\ of\ the\ second\ isotope})+(\frac {\%\ of\ the\ third\ isotope}{100}\times {Mass\ of\ the\ third\ isotope})[/tex]
Given that:
For first isotope, X-28 :
% = 92.23 %
Mass = 27.977 amu
For second isotope, X-29:
% = 4.67 %
Mass = 28.976 amu
For third isotope, X-30:
% = 3.10 %
Mass = 29.974 amu
Thus,
[tex]Average\ atomic\ mass=\frac{92.23}{100}\times {27.977}+\frac{4.67}{100}\times {28.976}+\frac{3.10}{100}\times {29.974}[/tex]
[tex]Average\ atomic\ mass=25.8031871+1.3531792+0.929194\ amu[/tex]
Average atomic mass = 28.0855603 amu ≅ 28.086 amu
This mass corresponds to Silicon, ( Z = 14).
How much ch2o is needed to prepare 445 ml of a 2.65 m solution of ch2o?
Answer: 35.4 grams
Explanation:
Molarity of a solution is defined as the number of moles of solute dissolved per Liter of the solution.
[tex]Molarity=\frac{n\times 1000}{V_s}[/tex]
where,
Molality = 2.65
n= moles of solute =?
[tex]V_s[/tex] = volume of solution in ml = 445 ml
Putting in the values we get:
[tex]2.65=\frac{n\times 1000}{445ml}[/tex]
[tex]n=1.18[/tex]
Mass of solute in g=[tex]moles\times {\text {molar mass}}=1.18mol\times 30.02g/mol=35.4g[/tex]
Thus 35.4 grams of [tex]CH_2O[/tex] is needed to prepare 445 ml of a 2.65 m solution of [tex]CH_2O[/tex].
Final answer:
To prepare 445 mL of a 2.65 M solution of CH2O, 35.42 grams of CH2O are needed. The calculation involves converting volume to liters, calculating moles required using molarity, and then finding the mass needed by multiplying with the molar mass of CH2O.
Explanation:
The question asks, how much CH2O is needed to prepare 445 ml of a 2.65 M solution of CH2O? In chemistry, the concentration of a solution is typically expressed in molarity (M), which is defined as moles of solute per liter of solution. To calculate the amount of CH2O needed, we use the formula:
Moles of solute = Molarity (M) × Volume of solution (L)
First, convert the volume of the solution from milliliters to liters:
445 mL = 0.445 L
Then, use the molarity and the volume of the solution to find the moles of CH2O needed:
Moles of CH2O = 2.65 M × 0.445 L = 1.17925 moles
To find the mass of CH2O required, multiply the moles by the molar mass of CH2O (approximately 30.03 g/mol):
Mass of CH2O = 1.17925 moles × 30.03 g/mol = 35.42 grams
Therefore, to prepare 445 mL of a 2.65 M solution of CH2O, 35.42 grams of CH2O are needed.
Elements in the same column of the periodic table have what in common?
Answer:
Elements in same column of periodic table have same properties.
Explanation:
The elements in the same group have same number of valance electrons thus have similar properties.
Consider the elements of group two i.e alkaline earth metals. All have two valance electrons and show similar properties.
Magnesium, barium, calcium etc.
All alkaline earth metals form salt with halogens.e.g,
Mg + Cl₂ → MgCl₂
Ba + Br₂ → BaBr₂
Mg + Br₂ → MgBr₂
Ca + Br₂ → CaBr₂
They react with oxygen and form oxides of respective metal.
2Mg + O₂ → 2MgO
2Ba + O₂ → 2BaO
2Ca + O₂ → 2CaO
these oxides form hydroxide when react with water,
MgO + H₂O → Mg(OH)₂
BaO + H₂O → Ba(OH)₂
CaO + H₂O → Ca(OH)₂
With nitrogen it produced nitride,
3Mg + N₂ → Mg₃N₂
3Ba + N₂ → Ba₃N₂
3Ca + N₂ → Ca₃N₂
With acid like HCl,
Mg + 2HCl → MgCl₂ + H₂
Ba + 2HCl → BaCl₂ + H₂
Ca + 2HCl → CaCl₂ + H₂
Elements in the same column of the periodic table have the same number of valence electrons in their outer shell, which leads to similar chemical properties. This includes similarities in bonding with other elements and changes in atomic size as we move down the column.
Explanation:Elements in the same column of the periodic table, also known as a chemical group, share similar chemical properties. This arises because they have the same number of valence electrons in their outer shells, which determines how they interact and bond with other elements. For example, Lithium (Li) and Sodium (Na), both in the first column, exhibit comparable chemical behaviors because they each have one valence electron in their outer shell.
The similarity in behavior extends to other attributes as well. As we move down any given group, the atomic size tends to increase, which also impacts the chemical properties of the elements. Each column in the periodic table is a unique group that shares these properties, making the table a critical tool for understanding elemental behaviors and relationships.
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A. Gallium is produced by the electrolysis of a solution obtained by dissolving gallium oxide in concentrated NaOH(aq). Calculate the amount of Ga (s) that can be deposited from a Ga (III) solution by a current of 0.790 A that flows for 30.0 min?
B. A current of 5.79 A is passed through a Sn (NO3)2 solution. How long in hours would this current have to be applied to plate out 8.70 g of tin?
Answer:
A)Mass of gallium plated out is 0.3440 grams
B) For 0.67 hours current of 5.79 A must to be applied to plate out 8.70 g of tin.
Explanation:
To calculate the total charge, we use the equation:
[tex]C=I\times t[/tex]
where,
C = Charge
I = Current in time t (seconds)
To calculate the moles of electrons, we use the equation:
[tex]\text{Moles of electrons}=\frac{C}{F}[/tex]
where,
F = Faraday's constant = 96500
A) The equation for the deposition of Ga(s) from Ga(III) solution follows:
[tex]Ga^{3+}(aq.)+3e^-\rightarrow Ga(s)[/tex]
I = 0.790 A, t = 30.0 min = 1800 seconds
[tex]C=I\times t[/tex]
[tex]C=0.790 A\times 1800 s=1422 C[/tex]
Moles of electron transferred:
[tex]=\frac{1422 C}{96500 F}=0.01474 mol[/tex]
Now, to calculate the moles of gallium, we use the equation:
[tex]\text{Moles of Gallium}=\frac{\text{Moles of electrons}}{n}[/tex]
n = number of electrons transferred = 3
[tex]\text{Moles of Gallium}=\frac{0.01474 mol}{3}=0.004913 mol[/tex]
Mass of 0.004913 moles of gallium = 0.004913 mol × 70 g/mol=0.3440 g
B) The equation for the deposition of Sn(s) from Sn(II) solution follows:
[tex]Sn^{2+}(aq.)+2e^-\rightarrow Sn(s)[/tex]
Moles of tin = [tex]\frac{8.70 g}{119 g/mol}=0.07311 mol[/tex]
n = number of electrons transferred = 2
[tex]\text{Moles of tin}=\frac{\text{Moles of electrons}}{n}[/tex]
Moles of electron = [tex]n\times \text{Moles of tin}[/tex]
[tex]=2\times 0.07311 mol=0.14622 mol[/tex]
Charge transferred during time t :
[tex]\text{Moles of electrons}=\frac{C}{F}[/tex]
[tex]C=96500 F\times 0.14622 mol=14,110.23 C[/tex]
Current applied for t time = I = 5.79 A
[tex]t=\frac{C}{I}=\frac{14,110.23 C}{5.79 A}=2,437 s=0.67 hrs[/tex]
For 0.67 hours current of 5.79 A must to be applied to plate out 8.70 g of tin.
Which two ions have the same electron configuration?
A) Na+ and O2- B) Li+ and F- C) Ca2+ and Br- D) Na+ and O3-
Answer: A) Na+ and O2-
Explanation:
To know the electronic configuration, one has to determine the numbers of electrons present in each atom.
Na+ means a sodium atom that has lost one valence electron. A Sodium atom initially has 11 electrons, but having lost an electron making it 10 electrons remaining with electron configuration of 1s2 2s2 2p6.
O2- means oxygen atom that has gained two valence electrons. An oxygen atom initially has 8 electrons, having gained two electrons makes it 10 electrons with electron configuration of 1s2 2s2 2p6. same as Na+
The purpose of gaining or losing electrons is to attain a stable duplet or octet structure.
The two ions with same electronic configuration are Na[tex]^+[/tex] and O²[tex]^-[/tex] .
What is electronic configuration?Electronic configuration is defined as the distribution of electrons of an atom or a molecule in orbitals of an atom or of a molecule.It describes each electron which is moving independently in it's orbital.
Electrons are able to move from one configuration to another by either absorption or emission of a quantum of energy, which is called as a photon.It is useful in understanding the structure of periodic table.
Considering the pair of sodium cation and oxygen anion the sodium atom with one positive charge has 10 electrons and oxygen anion with two negative charge has 10 electrons .
The elements with same number of electrons are called isoelectronic species.
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Sodium hypochlorite, NaOCl, is the active ingredient in household bleach. What is the concentration of hypochlorite ion if 20.00 cm3 of bleach requires 25.30 cm3 of 0.500 M HCl to reach the equivalence point?
a. 1.13 M
b. 0.132 M
c. 0.395 M
d. 0.632 M
Answer : The correct option is, (d) 0.632 M
Explanation : Given,
Concentration of HCl = 0.500 M
Volume of HCl = [tex]25.30cm^3=25.30mL=0.2530L[/tex]
conversion used : [tex]1cm^3=1mL\\1mL=0.001L[/tex]
Volume of hypochlorite ion = [tex]20.00cm^3=20.00mL=0.2000L[/tex]
The chemical reaction will be:
[tex]OCl^-+H^+\rightarrow HClO[/tex]
First we have to calculate the moles of [tex]H^+[/tex] ion.
[tex]\text{Moles of }H^+=\text{Concentration of }H^+\times \text{Volume of }H^+[/tex]
[tex]\text{Moles of }H^+=0.500M\times 0.2530L=0.1265mol[/tex]
From the reaction we conclude that,
Moles of [tex]H^+[/tex] = Moles of [tex]ClO^-[/tex] = 0.1265 mol
Now we have to calculate the concentration of hypochlorite ion.
[tex]\text{Moles of }ClO^-=\text{Concentration of }ClO^-\times \text{Volume of }ClO^-[/tex]
[tex]0.1265mol=\text{Concentration of }ClO^-\times 0.2000L[/tex]
[tex]\text{Concentration of }ClO^-=0.632M[/tex]
Therefore, the concentration of hypochlorite ion is 0.632 M.
If a gaseous mixture is made by combining 3.78 g Ar and 3.27 g Kr in an evacuated 2.50 L container at 25.0 ∘ C, what are the partial pressures of each gas, P Ar and P Kr, and what is the total pressure, P total, exerted by the gaseous mixture?
Answer:
The partial pressure of Ar = 0.925 atm
The partial pressure of Kr = 0.381 atm
The total pressure = 1.306 atm
Explanation:
Step 1: Data given
Mass of Ar = 3.78 grams
Mass of Kr = 3.27 grams
Volume = 2.50 L
Temperature = 25.0 °C
Molar mass of Ar = 39.95 g/mol
Molar mass of Kr = 83.80 g/mol
Step 2: Calculate moles of Ar
Moles Ar = mass Ar / molar mass Ar
Moles Ar = 3.78 grams / 39.95 g/mol
Moles Ar = 0.0946 moles
Step 3: Calculate moles of Kr
Moles Kr = 3.27 grams / 83.80 g/mol
Moles Kr = 0.039 moles
Step 4: Calculate partial press of each gas
p*V = n*R*T
⇒ p =the partial pressure of the gas
⇒ V = the volume in the container = 2.50 L
⇒ n = the number of moles of the gas
⇒ R = the gasconstant = 0.08206 L*atm/K*mol
⇒ T = the temperature = 25°C = 298 K
The partial pressure of Ar = (n*R*T)/V
p(Ar) = (0.0946*0.08206*298)/ 2.5
p(Ar)= 0.925 atm
p(Kr) = (0.039*0.08206*298)/ 2.5
p(Kr) = 0.381 atm
Step 5: Calculate the total pressure
The total pressure = p(Ar) +p(Kr)
Total pressure = 0.925 atm + 0.381 atm = 1.306 atm
A sample of hydrogen gas was collected over water at 36°C and 855 mm Hg. The volume of the container was 6.50 L. Calculate the mass of H2(g) collected. (Vapor pressure of water = 44.6 torr at 36°C)
Answer:
The amount of hydrogen gas collected will be 0.5468 g
Explanation:
We are given:
Vapor pressure of water = 44.6 torr = 44.6 mm Hg
Total vapor pressure = 855 mm Hg
Vapor pressure of hydrogen gas = Total vapor pressure - Vapor pressure of water = (855 - 44.6) mmHg = 810.4 mmHg
To calculate the amount of hydrogen gas collected, we use the equation given by ideal gas which follows:
[tex]PV=nRT[/tex]
where,
P = pressure of the gas = 810.4 mmHg
V = Volume of the gas = 6.50 L
T = Temperature of the gas = [tex]36^oC=[36+273]K=309K[/tex]
R = Gas constant = [tex]62.3637\text{ L.mmHg }mol^{-1}K^{-1}[/tex]
n = number of moles of hydrogen gas = ?
Putting values in above equation, we get:
[tex]810.4mmHg\times 6.50L=n\times 62.3637\text{ L.mmHg }mol^{-1}K^{-1}\times 309K\\\\n=\frac{810.4\times 6.50}{62.3637\times 309}=0.2734\ mol[/tex]
To calculate the mass from given number of moles, we use the equation:
[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex]
Moles of hydrogen gas = 0.2734 moles
Molar mass of hydrogen gas = 2 g/mol
Putting values in above equation, we get:
[tex]0.2734mol=\frac{\text{Mass of hydrogen gas}}{2g/mol}\\\\\text{Mass of hydrogen gas}=(0.2734mol\times 2g/mol)=0.5468g[/tex]
Hence, the amount of hydrogen gas collected will be 0.5468 g
What is the final temperature in a squeezed cold pack that contains 48.5 g of NH4NO3 dissolved in 125 mL of water? Assume a specific heat of 4.18J/(g⋅∘C) for the solution, an initial temperature of 27.5 ∘C, and no heat transfer between the cold pack and the environment.
Answer:
ΔT = - 2.13°C
Explanation:
Given data:
Mass of NH₄NO₃ = 48.5 g
Specific heat of solution = 4.18 j/g.°C
Initial temperature = 27.5°C
Final temperature = ?
Solution:
First of all we will find the moles of NH₄NO₃.
Number of moles = mass/molar mass
Number of moles = 48.5 g/80 g/mol
Number of moles = 0.6 mol
Now we will find the ΔH when we dissolve the 0.6 mol.
NH₄NO₃ + H₂O → NH₄NO₃ ΔH = +25.7 kJ
For 0.6 mol:
0.6 mol × +25.7 kJ/mol = 15.42 kj
15.42kj heat is absorbed by the reaction while -15.42 kj (-1542 j) heat will lost by the water.
The mass of water+ NH₄NO₃ = 125 g + 48.5 g
The mass of water+ NH₄NO₃ = 173.5 g
Q = m.c. ΔT
ΔT = T2 - T1
-1542 j = 173.5 g . 4.18 j/g.°C. ΔT
-1542 j = 725.23 j/°C. ΔT
ΔT = -1542 j / 725.23 j/°C
ΔT = - 2.13°C
Based on the data given, the final temperature in a squeezed cold pack is 6.2° C.
What is the final temperature in a squeezed cold pack that contains 48.5 g of NH4NO3 dissolved in 125 mL of water?The moles of NH₄NO₃ is determined using the formula:
Number of moles = mass/molar massmolar mass of NH₄NO₃ = 80 g/mol
Number of moles = 48.5/80
Number of moles = 0.6 moles
ΔH for the dissolution of 1 mole NH₄NO₃ = +25.7 kJ
ΔH for the dissolution of 0.6 mol = 0.6 × 25.7 kJ/mol
ΔH for the dissolution of 0.6 mol = 15.42 kj
Thus, 15.42 kJ heat is absorbed by the reaction while 15.42 kj heat will lost by the water.
Using the formula, Q = mcΔT to calculate the final temperature
mass of solution = 125 g + 48.5 g
mass of solution, m = 173.5 g
ΔT = T2 - T1
Q = 15.42 Kj = -15420 J
-15420 = 173.5 * 4.18 * ΔT
ΔT = -15420 / 725.23
ΔT = - 21.3° C
Final temperature, T2 = ΔT + T1
Final temperature, T2 = - 21.3° C + 27.5° C
Final temperature, T2 = 6.2° C
Therefore, the final temperature in a squeezed cold pack is 6.2° C.
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Water has the following thermodynamic values: ΔH°fus of H2O = 6.02 kJ/mol ΔH°vap of H2O = 40.7 kJ/mol heat capacity of solid H2O = 2.09 J/g°C heat capacity of liquid H2O = 4.18 J/g°C heat capacity of gaseous H2O = 1.97 J/g°C
How much energy (in kJ) is required to raise the temperature of 25.0 g of H2O from -129°C to 262°C?
Enter your answer in units of kJ to three significant figures.
Answer:
Qtotal = 90.004 kJ
Explanation:
To start resolving the problem we need to first convert the kJ/mol units from the thermodynamic values to J/g, so that we can work with the units of the heat capacity values. We know that the molar mass of water is 18.015 g/mol, so with this we do the respective conversion:
ΔH°fus of H2O = (6.02 kJ/mol) (1 mol/18.015g) (1000J/kJ) = 334.165 J/g
ΔH°vap of H2O = (40.7 kJ/mol) (1mol/18.015g) (1000J/kJ) = 2259.228 J/g
Now we need to find out the heat energy required to rise the temperature (specific heat capacity) and the energy required for each change of phase (specific latent heat), and add everything up. For this we will require the specific heat capacity and latent heat equations:
Q = mCΔT ; where m = mass, C = Hear capacity, ΔT = change of temperature
Q = mL ; where m = mass, L = specific latent heat
First change of phase (solid to liquid - fusion)
Q1 = (25g) (2.09 J/g°C) (0°C - (-129°C) = 6740.25 J
Q2 = (25g) (334.165 J/g) = 8354.125 J
Second change of phase (liquid to gas - vaporization)
Q3 = (25g) (4.18 J/g°C) (100°C - 0°C = 10450 J
Q4 = (25g) (2259.228 J/g) = 56480.7 J
Rise of temperature of the gaseous water
Q5 = (25g) (1.97 J/g°C) (262°C - 100°C = 7978.5 J
Finally we add everything up:
Qtotal = Q1 + Q2 + Q3 + Q4 + Q5 = 6740.25 J + 8354.125 J + 10450 J + 56480.7 J + 7978.5 J = 90003.575 J = 90.004 kJ
Change of state has to do with the movement from one state of matter to another.
Change of stateChange of state has to do with the movement from one state of matter to another. We need to first change the kJ/mol units to J/g,knowing that the molar mass of water is 18.015 g/mol hence:
ΔH°fus of H2O = (6.02 kJ/mol) (1 mol/18.015g) (1000J/kJ) = 334.165 J/g
ΔH°vap of H2O = (40.7 kJ/mol) (1mol/18.015g) (1000J/kJ) = 2259.228 J/g
For each phase change;
Q = mCΔT
where
m = mass, C = Hear capacity, ΔT = change of temperatureAnd
Q = mL
where
m = mass, L = specific latent heatFirst, solid to liquid change
Q1 = (25g) (2.09 J/g°C) (0°C - (-129°C) = 6740.25 J
Q2 = (25g) (334.165 J/g) = 8354.125 J
Second liquid to gas change
Q3 = (25g) (4.18 J/g°C) (100°C - 0°C) = 10450 J
Q4 = (25g) (2259.228 J/g) = 56480.7 J
Then,
Q5 = (25g) (1.97 J/g°C) (262°C - 100°C) = 7978.5 J
Finally:
Qtotal = Q1 + Q2 + Q3 + Q4 + Q5 = 6740.25 J + 8354.125 J + 10450 J + 56480.7 J + 7978.5 J = 90003.575 J = 90.004 kJ
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Part C What is a reaction mechanism?
What is a reaction mechanism?
A reaction mechanism is an overall reaction that occurs with necessary values such as activation energy, temperature which explain the experimentally determined rate law.
A reaction mechanism is a rate-determining step of the reaction that describe how fast an overall reaction occurs and explain the limiting factors of reactions rate.
A reaction mechanism is a series of elementary reactions that describe how an overall reaction occurs and explain the experimentally determined rate law.
Answer:
A reaction mechanism is a series of elementary reactions that describe how an overall reaction occurs and explain the experimentally determined rate law.
Explanation:
A reaction machanism is a succession of steps to go from the reactants to the products of a reaction.
Each of this steps is a different elementary reaction and produces an intermediary product. This intermediaries not always can be seen in real life due to the high rate of reaction of following steps.
This intermediary reactions where created to explain the experimental determined rate law of some reactions, that doesn't fit in a one-step reaction.
In conclusion we can say that: A reaction mechanism is a series of elementary reactions that describe how an overall reaction occurs and explain the experimentally determined rate law
Final answer:
A reaction mechanism explains the step-by-step sequence in which reactants are converted into products, detailing elementary reactions that make up the entire process, including the rate-determining step that dictates the overall rate of the reaction.
Explanation:
A reaction mechanism is the detailed process by which a chemical reaction occurs, broken down into a series of elementary steps. Each of these steps involves a certain number of reactant species, as detailed by the molecularity (unimolecular, bimolecular, or termolecular) of the reaction. The overall rate of the chemical reaction is determined by the rate-determining step, which is the slowest step within the reaction mechanism. The rate laws for the elementary reactions must align with the experimentally determined rate law to confirm the proposed reaction mechanism as plausible.
Catalysts are substances that alter the reaction mechanism, offering an alternative pathway with a lower activation energy, which in turn affects the reaction rate without impacting the chemical equilibrium of the reaction.
A balanced chemical equation alone does not convey the complexity of the reaction mechanism. For example, the decomposition of ozone is a multi-step process, not evident from the simple overall equation. The mechanism provides a detailed description of these steps, much like a roadmap of a journey illustrating every turn and stop, rather than just showing the start and end points.
Based on the diagram below, which would have the most inertia?
The sphere on the left, because it has more mass
The sphere on the right because it has less mass
The sphere on the left because it is a bigger diameter
The sphere on the right because it is a smaller diameter
Answer:
The sphere on the left has the most inertia because it has more mass.
Explanation:
Inertia is a property of matter of a substance.
According to Newton's first law of motion, a body continues to stay in the state of rest or constant velocity unless acted upon a external force.
The amount of inertia that an object possess is proportional to the mass of the object.
The sphere on the left is of 300 kg and that on the right is of 30 kg.
Clearly, the sphere on the left has more mass.
Therefore, the sphere on the left has the most inertia.
Answer:
it would be the sphere on the left that has more mass
Explanation:
because the more weight that is applied to a force with being a small object appling force upon it it will be harder to move
If a chemical with a toxicity level of 1 is mixed with a different chemical with a toxicity level of 1, the combined effect of exposure to the mixture is 1. This is an example of chemical mixtures interacting through:
a. amplification
b. feedback loop
c. antagonism
d. synergy
e. additivity
Answer:
c. antagonism
Explanation:
The toxic effect is that produced by one or several toxic agents on an organism, population or community that is manifested by biological changes. Its degree is assessed by an intensity or severity scale and its magnitude is related to the dose (amount of substance administered, usually expressed per unit of body weight) or the concentration (substance applied in the medium) of the toxic agent.
The effect can be:
- Quantum: consisting of the presence or absence of a characteristic (eg death or existence of tumors).
- Lethal: death by direct action as a result of exposure to a certain concentration of a toxic agent.
- Sublethal: occurs below the level that causes death as a direct result of exposure to a certain concentration of a toxic agent.
- Acute: that caused by the action of chemical substances on living organisms, which manifests rapidly and severely (after a short period of exposure: 0 - 96 h, typically.).
- Chronic: one that occurs, in general, after a prolonged period of exposure (usually manifests after days or years, depending on the species).
- Additive: the magnitude of the effect or simultaneous response of two or more substances is equal to the sum of the effects or responses of each.
- Combined: when two or more substances applied at the same time produce different effects or have different modes of action.
- Enhancement or synergism: when the toxicity of a mixture of chemical agents is greater than expected by the simple sum of the toxicities of the individual agents present in the mixture.
- Inhibition or antagonism: when the toxicity of a mixture of chemical agents is lower than expected by the simple sum of the toxicities of the individual agents present in the mixture.
The alpha decay of what isotope of what element produces lead-206? The alpha decay of what isotope of what element produces lead-206? mercury-202 thallium-204 bismuth-208 polonium-210 radon-222
Answer : The element produces lead-206 is, polonium (Po)- 210
Explanation :
Alpha decay : In this process, alpha particles is emitted when a heavier nuclei decays into lighter nuclei. The alpha particle released has a charge of +2 units.
The general representation of alpha decay reaction is:
[tex]_Z^A\textrm{X}\rightarrow _{Z-2}^{A-4}Y+_2^4\alpha[/tex]
As we are given that,
[tex]_{Z-2}^{A-4}Y=_{82}^{206}Pb[/tex]
From the given data we conclude that,
[tex]Z-2=82\\\\Z=82+2=84\\\\A-4=206\\\\A=206+4=210[/tex]
So, the element is polonium (Po) that has atomic number 84 and atomic mass 210.
The complete alpha decay reaction will be,
[tex]_{84}^{210}\textrm{Po}\rightarrow _{82}^{206}\textrm{Pb}+_2^4He[/tex]
Hence, the element produces lead-206 is, polonium (Po)- 210
Electrons do not usually flow through the electron-transport chain to O2, unless ADP is simultaneously phosphorylated to _____.
Answer:
ATP
Explanation:
The main purpose for cellular respiration, is to finally obtain ATP (Adenosine Triphosphate), this process occurres through the electron transport chain: this is the final step of the aerobic respiration, and takes place when energy from NADH and FADH₂ (both products from Krebs Cycle) is transferred to ATP
This process occurres within the inner membrane of the mitochondria: while protons (H⁺) pass through the ATP synthase (this protein acts as a “tunnel” where H⁺ go through), which uses the difference of protons (H⁺) concentration between the matrix (between 2 mitochondrial membranes) and the inner matrix of mitochondria.
The ATP synthase also acts as an enzyme, creating ATP using ADP + Pi (inorganic phosphorus)
The electrons used to help with this process, finally attach to O₂ (oxygen) to form H₂O
Answer: The correct answer is : ATP
Explanation: The phosphorylation reaction is a type of metabolic reaction that results in the formation of (ATP) or (GTP) by the direct transfer and donation of a phosphoryl (PO3) group to (ADP) or (GDP) from a phosphorylated reactive intermediate. The breath is an ATP generating process in which an inorganic compound serves as the ultimate e-acceptor. O2 is delivered by blood flow.
When heated, calcium carbonate decomposes to yield calcium oxide and carbon dioxide gas via the reaction CaCO3(s)?CaO(s)+CO2(g)
What is the mass of calcium carbonate needed to produce 61.0L of carbon dioxide at STP?
Express your answer with the appropriate units.
Answer:
272.2 grams is the mass of calcium carbonate needed to produce 61.0L of carbon dioxide at STP
Explanation:
If the gas is produced at STP, by the volume and the Ideal Gas Law, we can know the moles.
P . V = n. R .T
1 atm . 61 L = n . 0.082L.atm/mol.K . 273K
61 L.atm / (0.082 mol.K/L.atm . 273K) = 2.72 moles
As the relation is 1:1
1 mol of CO₂ cames from 1 mol of CaCO₃, so 2.72 moles of CO₂ comes from 2.72 moles of CaCO₃
Molar mass CaCO₃ = 100.08 g/m
Moles . molar mass = grams
2.72 m . 100.08 g/m = 272.7 g
Name the following Structure:
Answer:
The correct answer is b) ethylmethylamine
Explanation:
This organic compound has the NH group (it is an amine), with 2 substitutions: a methyl group and an ethyl group.
Answer:
ethylmethylamine
Explanation:
The standard cell potential (E°cell) for the reaction below is +0.63 V. The cell potential for this reaction is ________ V when [ Zn2+] = 3.5 M and [Pb2+] = 2.0⋅10−4 M.
Pb2+ (aq) + Zn (s) → Zn2+ (aq) + Pb (s)
A) 0.84
B) 0.76
C) 0.50
D) 0.63
E) 0.39
Answer : The cell potential for this reaction is 0.50 V
Explanation :
The given cell reactions is:
[tex]Pb^{2+}(aq)+Zn(s)\rightarrow Zn^{2+}(aq)+Pb(s)[/tex]
The half-cell reactions are:
Oxidation half reaction (anode): [tex]Zn\rightarrow Zn^{2+}+2e^-[/tex]
Reduction half reaction (cathode): [tex]Pb^{2+}+2e^-\rightarrow Pb[/tex]
First we have to calculate the cell potential for this reaction.
Using Nernest equation :
[tex]E_{cell}=E^o_{cell}-\frac{2.303RT}{nF}\log \frac{[Zn^{2+}]}{[Pb^{2+}]}[/tex]
where,
F = Faraday constant = 96500 C
R = gas constant = 8.314 J/mol.K
T = room temperature = [tex]25^oC=273+25=298K[/tex]
n = number of electrons in oxidation-reduction reaction = 2
[tex]E^o_{cell}[/tex] = standard electrode potential of the cell = +0.63 V
[tex]E_{cell}[/tex] = cell potential for the reaction = ?
[tex][Zn^{2+}][/tex] = 3.5 M
[tex][Pb^{2+}][/tex] = [tex]2.0\times 10^{-4}M[/tex]
Now put all the given values in the above equation, we get:
[tex]E_{cell}=(+0.63)-\frac{2.303\times (8.314)\times (298)}{2\times 96500}\log \frac{3.5}{2.0\times 10^{-4}}[/tex]
[tex]E_{cell}=0.50V[/tex]
Therefore, the cell potential for this reaction is 0.50 V
Your task is to measure the amount of energy evolved during the combustion of some hydrocarbon. Which of the following would be the ideal technique for this experiment?
a.bomb manometry
b.coffee-cup calorimetry
c.bomb calorimetry
Answer:
c. Bomb calorimetry
Explanation:
The hydrocarbons are combustibles, it means that they can react in a combustion reaction to release energy. To measure this amount of energy, it's necessary equipment that the reaction can be placed in a controlled way. The bomb calorimeter is this equipment, which is an adiabatic vessel, with water. The heat is calculated based on the increase in the water temperature.
The coffee-cup calorimetry is used to measure the heat of a dissolution reaction and the bomb manometry is used to measure the pressure.
All isotopes of an element with an atomic number greater than ___ are radioactive.
Answer:
83 .
Explanation:
Radioactive elements: It is defined as the atoms which contains unstable nucleus because of the constantly change and imbalance of energy in the nucleus. Radioactivity of an atom is showing by when the nucleus of an atom loose a neutron, it gives an energy and this process is called to be radioactivity.
Isotopes elements containing different number of neutrons and same number of protons. All isotopes are not considered as radioisotopes. All isotopes of an element with an atomic number greater than 83 are radioactive means, they are having unstable nucleus.
The eight most common elements in Earth's crust are: O, Si, Al, Fe, Ca, Na, K, and Mg. These elements account for 98% of the atoms in Earth's crust. These eight elements combine chemically with one another to make six main minerals which account for 90% of the minerals in Earth's crust. These minerals, the so-called the rock forming minerals, are: feldspar, pyroxene, amphibole, mica and the last, made up of the two most abundant elements, is A) galena. B) gold. C) hematite. D) quartz.
Answer:
it's d
Explanation:
Feldspar, pyroxene, amphibole, mica and the last, made up of the two most abundant elements, is quartz.
What is element ?An element is a pure material that cannot be transformed into simpler compounds by any physical or chemical process. The atoms that make up an element are all the same kind.
There are three categories for elements are metals, nonmetals, and metalloids. The symbols used to symbolize different elements.
Any compound that cannot be broken down into simpler chemicals by regular chemical processes is referred to as a chemical element or element. The building blocks of which all matter is made are called elements.
Fire, Earth, Water, and Air. Earth, water, air, and fire were the four elements that the ancient Greeks thought made up everything.
Thus, option D is correct.
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A 670.-g piece of copper tubing is heated to 95.3°C and placed in an insulated vessel containing 52.5 g of water at 36.5°C. Assuming no loss of water and heat capacity of 10.0 J/K for the vessel, what is the final temperature (c of copper = 0.387 J/g · K)?
Answer:
Final temperature will be T = 67.68°C
Explanation:
The heat evolved by the copper tubing will be absrobed by both water and the vessel used.
The heat evolved by the copper tubing will be:
Heat = [tex]Q1=massXspecificheatX(changeintemperature)[/tex]
Mass = 670 g
Specific heat = 0.387 J/g · K
Change in temperature = Initial - Final
[tex]Q1=670X0.387X(ChangeinTemperature)[/tex]
The heat absorbed by water will be
[tex]Q2=massXspecificheatXchangeintemperature[/tex]
mass = 52.5
Specific heat = 4.184 J/g · K
the heat absorbed by vessel will be:
[tex]Q3=heatcapacityXchange intemperature[/tex]
Heat capacity = 10J/K
Final temperature of all the three will be same (say T)
[tex]Q1=Q2+Q3[/tex]
[tex]670X0.387X(ChangeinTemperature)=massXspecificheatXchangeintemperature+heatcapacityXchange intemperature[/tex]
[tex]670X0.387X(95.3-T)=(52.5X4.184X(T-36.5))+(10X(T-36.5)[/tex]
[tex]259.29(95.3-T)=219.66(T-36.5)+10(T-36.5)[/tex]
[tex]24710.337-259.29T=219.66T-8017.59+10T-365[/tex]
[tex]33092.59=488.95T[/tex]
T = 67.68°C
What would the volume (L) of 6.6 g of CO2 be if it were measured at the same temperature and pressure as that of the experiment (only 2 decimal places are needed)? Enter only the number of liters; do NOT include the "L" for liters.
Answer:
The correct answer is 3.36 L
Explanation:
The molecular weight of CO₂ is 44 g/mol (2 O + 1 C= (2 x (16 g/mol )) + 12 g/mol). We have 44 g in 1 mol CO₂, and we want to know how many mol are in 6.6 g:
44 g -------------- 1 mol CO₂
6.6 g -------------- X= 6.6 g x 1 mol / 44 g = 0.15 mol
In normal conditions of temperature and pressure, 1 mol of ideal gas occupies 22.4 L of volume, thus:
1 mol CO₂ ------------ 22.4 L
0.15 mol -------------- X= 3.36 L
So, 6.6 g CO₂ are equivalent to 0.15 mol CO₂ and they occupy 3.36 L.
When a solid is placed in a container and heat is applied, a phase change occurs. Watch the video and identify which of the following statements are correct. Check all that apply. View Available Hint(s) Check all that apply. The temperature increases while all of a liquid is converted to a gas. When a solid is converted to a liquid, heat is absorbed. The average kinetic energy of the system changes while all of a solid is converted to a liquid. Temperature remains constant while all of a solid is converted to a liquid. When heat is applied to a solid, the molecular motion decreases as the temperature increases.
Answer:
Explanation:"Watch the video and identify which of the following statements are correct." Excuse no video
Kinetic energy
Further Explanation
Energy is something that is very inherent in every activity of life. Simply stated, energy can be interpreted as the ability of an object to make an effort. An object is said to have energy when it is able to produce power that can work.
Kinetic, Potential, and Mechanical Energy is a type of energy that is almost present in every part of human life. Its existence cannot be eliminated because of its enormous benefits for the development of human technology, especially those relating to the movement of objects, the position of objects, or a combination of the two.
Kinetic energy is the energy of motion, the energy possessed by objects or objects due to their motion. Kinetic energy comes from the Greek word kinetics which means to move. So, you certainly know that every object that moves then that object has kinetic energy.
The kinetic energy of an object is defined as the effort needed to move an object with a certain mass from rest to a certain speed.
The kinetic energy of an object is equal to the amount of effort required to express its speed and rotation, starting from the others.
Kinetic energy is influenced by the mass and velocity of an object as it moves. The mass is symbolized by the letter m, while the speed is symbolized by the letter v. The amount of energy is directly proportional to the amount of mass and magnitude of the speed of an object as it moves.
Objects with large mass and velocity must have large kinetic energy when moving. And vice versa, objects whose mass and velocity are small, their kinetic energy is also small.
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Grade: High School
Subject: Chemistry
keywords: Energy, kinetic.
A sample of nickel is heated to 99.8 degrees C and placed in a coffee cup calorimeter containing 150.0g water at 23.5 degrees C. After the metal cools, the final temperature of metal andwater mixture is 25.0 degrees C. If the specific heat capacity of nickel is 0.444J/(degreesCg),
what mass of nickel was originally heated?
Answer: The mass of nickel that was originally heated is 28.4 grams.
Explanation:
When metal is dipped in water, the amount of heat released by metal will be equal to the amount of heat absorbed by water.
[tex]Heat_{\text{absorbed}}=Heat_{\text{released}}[/tex]
The equation used to calculate heat released or absorbed follows:
[tex]Q=m\times c\times \Delta T=m\times c\times (T_{final}-T_{initial})[/tex]
[tex]m_1\times c_1\times (T_{final}-T_1)=-[m_2\times c_2\times (T_{final}-T_2)][/tex] ......(1)
where,
q = heat absorbed or released
[tex]m_1[/tex] = mass of nickel = ?
[tex]m_2[/tex] = mass of water = 150.0 g
[tex]T_{final}[/tex] = final temperature = 25.0°C
[tex]T_1[/tex] = initial temperature of nickel = 99.8°C
[tex]T_2[/tex] = initial temperature of water = 23.5°C
[tex]c_1[/tex] = specific heat of nickel = 0.444 J/g°C
[tex]c_2[/tex] = specific heat of water= 4.186 J/g°C
Putting values in equation 1, we get:
[tex]m_1\times 0.444\times (25.0-99.8)=-[150.0\times 4.186\times (25.0-23.5)][/tex]
[tex]m_1=28.4g[/tex]
Hence, the mass of nickel that was originally heated is 28.4 grams.
Answer: 28.3 grams
Explanation:
[tex]heat_{absorbed}=heat_{released}[/tex]
As we know that,
[tex]Q=m\times c_1\times \Delta T=m\times c_2\times (T_{final}-T_{initial})[/tex]
[tex]m_1\times c_1\times (T_{final}-T_1)=-[m_2\times c_2\times (T_{final}-T_2)][/tex] .................(1)
where,
q = heat absorbed or released
[tex]m_1[/tex] = mass of water= 150.0 g
[tex]m_2[/tex] = mass of nickel = ?
[tex]T_{final}[/tex] = final temperature = [tex]25^oC=(273+25)K=298K[/tex]
[tex]T_1[/tex] = temperature of water = [tex]23.5^oC=(273+23.5)K=296.5K[/tex]
[tex]T_2[/tex] = temperature of nickel = [tex]99.8^oC=273+99.8=372.8K[/tex]
[tex]c_1[/tex] = specific heat of water = [tex]4.184J/g^0C[/tex]
[tex]c_2[/tex] = specific heat of nickel= [tex]0.444J/g^0C[/tex]
Now put all the given values in equation (1), we get
[tex]150.0\times 4.184\times (298-296.5)=-[m_2\times 0.444\times (298-372.8)][/tex]
[tex]m_2=28.3g[/tex]
Therefore, the mass of nickel originally heated was 28.3 grams
Calculate the grams of so2 gas present at stp in a 5.9 l container.
Answer: The mass of sulfur dioxide gas at STP for given amount is 16.8 g
Explanation:
At STP conditions:
22.4 L of volume is occupied by 1 mole of a gas.
So, 5.9 L of volume will be occupied by = [tex]\frac{1mol}{22.4L}\times 5.9L=0.263mol[/tex]
Now, to calculate the mass of a substance, we use the equation:
[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex]
Moles of sulfur dioxide gas = 0.263 mol
Molar mass of sulfur dioxide gas = 64 g/mol
Putting values in above equation, we get:
[tex]0.263mol=\frac{\text{Mass of sulfur dioxide gas}}{64g/mol}\\\\\text{Mass of sulfur dioxide gas}=(0.263mol\times 64g/mol)=16.8g[/tex]
Hence, the mass of sulfur dioxide gas at STP for given amount is 16.8 g