Answer:
Phosphorus cycle
Explanation:
Biogeochemical cycle, any of the natural pathways by which essential elements of living matter are circlated.
There are four types of biogeochemical cycle, they are ; water cycle,carbon cycle,nitrogen cycle and phosphorous cycle
Carbon cycle is the cycle in which photosynthesis and cellular respiration take place.
Water cycle involves transpiration.
Nitrogen cycle Is the cycle that is dependent upon bacteria for nitrogen fixation and denitrification.
Phosphorus cycle is one of the slowest biogeochemical cycle. It does not stay in the atmosphere, because it is normally in a liquid state at room temperature. It does not include the atmosphere.
Final answer:
The phosphorus cycle is the biogeochemical cycle that does not include an atmospheric component, differentiating it from cycles like water, carbon, and nitrogen.
Explanation:
The biogeochemical cycle that does not include the atmosphere is the phosphorus cycle. Unlike the water, carbon, and nitrogen cycles, the phosphorus cycle does not involve the atmospheric pathway. Phosphorus mainly cycles through rocks, soil, water, and living organisms. It is essential for life as part of DNA, RNA, and ATP molecules, which are vital for genetic information and energy transfer in cells. However, phosphorus doesn't enter the atmosphere in a gaseous phase; hence, it is distinct amongst biogeochemical cycles.
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).
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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A certain substance X condenses at a temperature of 123.3 degree C . But if a 650. g sample of X is prepared with 24.6 g of urea ((NH2)2 CO) dissolved in it, the sample is found to have a condensation point of 124.3 degree C instead. Calculate the molal boiling point elevation constant Kb of X.Round your answer to 2 significant digits.
Answer:
The molal boiling point elevation constant is 1.59 ≈ 1.6 [tex]Kkgmol^{-1}[/tex]
Explanation:
To solve this question , we will make use of the equation ,
Δ[tex]T_{b} = i*K_{b} *m[/tex]
where ,
Δ[tex]T_{b}[/tex] is the change in boiling point of the substance [tex]X[/tex] ( °[tex]C[/tex] or [tex]K[/tex])[tex]i[/tex] is the Vant Hoff Factor which = 1 in this case ( no unit )[tex]K_{b}[/tex] is the mola boiling point elevation constant of X ( [tex]Kkgmol^{-1}[/tex])[tex]m[/tex] is the molality of the solution which has [tex](NH_{2})_{2} CO[/tex] as the solute and [tex]X[/tex] as the solution ([tex]molkg^{-1}[/tex])Δ[tex]T_{b}[/tex] = [tex]124.3 -123.3 = 1[/tex] °[tex]C[/tex] or [tex]K[/tex];[tex]i[/tex]=1;[tex]m[/tex]= [tex]\frac{moles of solute}{weight of solvent(kg)}[/tex][tex]molkg^{-1}[/tex]∴ [tex]m = \frac{\frac{24.6}{60} }{\frac{650}{1000} }[/tex]
as the weight of [tex](NH_{2})_{2} CO[/tex] is [tex]60g[/tex] and thus number of moles = [tex]\frac{24.6}{60}[/tex]and the weight of solvent in [tex]kg[/tex] is [tex]\frac{650}{1000}[/tex]4. [tex]K_{b}[/tex] ⇒ ?
∴
[tex]1=1*K_{b} *\frac{\frac{24.6}{60} }{\frac{650}{1000} }[/tex]
⇒ [tex]K_{b}[/tex] = [tex]1.59[/tex] ≈ 1.6 [tex]Kkgmol^{-1}[/tex]
The molal boiling point elevation constant (Kb) of substance X is 4.1.
Explanation:The molal boiling point elevation constant (Kb) can be calculated using the formula: ΔT = Kb × m
Where ΔT is the change in boiling point, Kb is the molal boiling point elevation constant, and m is the molality of the solution.
In this case, the change in boiling point (ΔT) is 1 degree C (124.3 - 123.3), the molality (m) can be calculated by dividing the molal mass of urea by the mass of the solvent water, which gives a value of 0.0246 kg urea / 0.100 kg water = 0.246 mol/kg, and the formula becomes: 1 = Kb × 0.246
Now, rearrange the equation to solve for Kb: Kb = 1 / 0.246 = 4.07
Rounding to 2 significant digits, the molal boiling point elevation constant Kb of substance X is 4.1.
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.
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.
In cellular chemical pathways, the product(s) of any particular reaction are often quickly consumed by the next reaction in the pathway. This would tend to keep the product concentration ___ and drive the reaction ____.
Answer:
Tend to keep the product concetration low and therefore drive the reaction righward
Explanation:
The fact the products of a reaction are quickly consumed by the next one would tend to keep the product concetration low and therefore drive the reaction righward (to the products).
This happens because the system will not achive equilibrium between the reactants and the product, and will keep producing it util the system achives equilibrium or the reactants dry out.
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.
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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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
A voltaic cell is constructed with an Ag/Ag+ half-cell and a Pb/Pb2+ half-cell. Measurement shows that the silver electrode is positive.
(a) Write balanced half-reactions and the overall spontaneous reaction. (Type your answer using the format [NH4]+ for NH4+. Use the lowest possible coefficients.)
reduction:
__Ag+(aq) + __e- -> ___(s)
oxidation:
__(s) ->__Pb2+(aq) +__e-
overall reaction:
__Ag+(aq) +__(s) ->__(s) + __ Pb2+(aq)
(b) The cation flow is towards which electrode?
lead OR silver
What process occurs at the lead electrode?
oxidation OR reduction
In which direction do the electrons flow?
from the lead electrode to the silver electrode OR from the silver electrode to the lead electrode
Answer:
a) Reduction:
Ag⁺(aq) + e⁻ → Ag(s)
Oxidation:
Pb(s) → Pb⁺²(aq) + 2e⁻
Overall reaction:
2Ag⁺(aq) + Pb(s) → 2Ag(s) + Pb²⁺
b) Silver; oxidation; from the lead electrode to the silver electrode.
Explanation:
a) Ag⁺ had lost 1 electron, so need to gain 1 electron to become Ag(s). Pb needs to lose 2 electrons to become Pb⁺².
Reduction:
Ag⁺(aq) + e⁻ → Ag(s)
Oxidation:
Pb(s) → Pb⁺²(aq) + 2e⁻
Overall reaction:
2Ag⁺(aq) + Pb(s) → 2Ag(s) + Pb²⁺ (it will need 2Ag⁺ to gaind the 2 electrons released by Pb)
b) The cation formed in the redox reaction is Pb²⁺, so, to equilibrate the charges, it will flow towards the silver (Ag) electrode.
The lead (Pb) is being oxidized, so oxidation is happening at it.
The electrons flow from the oxidation (anode) to the reduction (cathode), so they flow from the lead electrode to the silver electrode.
In the voltaic cell, the Ag+ is reduced to Ag in the silver half-cell, while Pb is oxidized to Pb2+ in the lead half-cell. The cations flow towards the silver electrode and the electrons flow from the lead to the silver electrode. Hence, the overall reaction is 2Ag+(aq) + Pb(s) -> 2Ag(s) + Pb2+(aq).
Explanation:In a voltaic cell with an Ag/Ag+ half-cell and a Pb/Pb2+ half-cell, the silver half-cell acts as the cathode or reduction half-cell which gains electrons, while the lead half-cell acts as the anode or oxidation half-cell and loses electrons. Therefore, the balanced half-reactions and overall spontaneous reactions are:
(a) Balanced Half-Reactions and Overall Reaction:
Reduction: Ag+(aq) + 1e- -> Ag(s)
Oxidation: Pb(s) -> Pb2+(aq) + 2e-
Overall Reaction: 2Ag+(aq) + Pb(s) -> 2Ag(s) + Pb2+(aq)
(b) The Cation Flow and Electrons Flow:
The cation flow is towards the silver electrode and the electron flow is from the lead electrode to the silver electrode. In the voltaic cell, the process that occurs at the lead electrode is oxidation.
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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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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
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
George is writing an essay about the role of observation and inference in the development of the atomic theory. He wants to explain why it was more difficult to observe the presence of neutrons in atoms. Which two statements should he include in his essay?
George should include two main points: First, the hypothesis of the existence of neutrons arose from the need to explain the remaining mass in an atom's nucleus not accounted for by protons. Second, the detection of neutrons was especially difficult due to their lack of charge, which required more advanced techniques to observe.
Explanation:In his essay, George should include the following statements:
The nucleus of an atom contains most of its mass, and although the number of protons was determined, they only accounted for half, or less, of that mass. This led to the hypothesis of the existence of neutral particles in the nucleus — known as neutrons.Detecting neutrons was more difficult because they were uncharged particles. It wasn't until 1932 that physicist James Chadwick found evidence of neutrons, uncharged, subatomic particles with a mass approximately the same as that of protons.Understanding the nature of neutrons was a significant step in the development of atomic theory, as it helped explain isotopes and variants of a particular chemical element that differ in neutron number.
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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.
Why does ionization energy decrease moving down a group in the periodic table?
Answer:
Electron shielding
Explanation:
Ionization energy decreases moving down a group in the periodic table because of a phenomen known as Electron shielding, in which valence electrons do not interact with the positively charged nucleus as strongly as inner electrons do, because these inner electrons shield the valence electrons. This means it's easier for these valence electrons to leave the atom the more inner electrons are between them and the nucleus, this translates into a decreased ionization energy value.
Ionization energy decreases moving down a group due to the increased distance of the valence electrons from the nucleus, the greater shielding effect of inner electrons, and the higher principal quantum number of the valence electrons, which reduces the effective nuclear charge.
Ionization energy refers to the amount of energy required to remove an electron from an atom in the gaseous state. A key periodic trend observed is that ionization energy decreases as we move down a group in the periodic table. There are several reasons for this trend:
As atomic size increases down a group, the outermost, or valence, electrons are further from the nucleus, experiencing a weaker attraction due to increased distance.The shielding effect comes into play; inner shell electrons block the pull of the positively charged nucleus on the outer electrons, making them easier to remove.The increase in principal quantum number (n) down a group means that valence electrons are in higher energy levels, further away from the nucleus, thereby decreasing effective nuclear charge (Zeff) on these electrons.For example, within Group 1 of the periodic table, which contains the alkali metals, we notice a significant drop in ionization energy from lithium to cesium as each succeeding element has more filled inner electron shells that shield the outer electron. Furthermore, the increase in atomic number down a group does not proportionately increase the nuclear charge's effect on the valence electrons due to the reasons mentioned above.
In summary, the larger atomic radius and greater shielding by inner electrons result in a reduced attraction between the valence electrons and the nucleus, leading to a decrease in ionization energy down a group.
Given the partial equation ? MnO4−+ ? SO32− → ? Mn2++ ? SO42− what must the coefficients be so that the electrons are balanced? Enter the equation coefficients in order separated by commas (e.g., 2,2,1,4, where 1 indicates the absence of a coefficient).
Answer:
The coefficients should be: 2, 5, 2, 5
Explanation:
Given redox reaction: MnO₄⁻ + SO₃²⁻ → Mn²⁺+ SO₄²⁻
To balance the given redox reaction in acidic medium, the oxidation and the reduction half-reactions should be balanced first.
Reduction half-reaction: MnO₄⁻ → Mn²⁺
Oxidation state of Mn in MnO₄⁻ is +7 and the oxidation state of Mn in Mn²⁺ is +2. Therefore, Mn accepts 5e⁻ to get reduced from +7 to +2 oxidation state.
⇒ MnO₄⁻ + 5e⁻ → Mn²⁺
Now the total charge on reactant side is (-6) and the total charge on product side is +2. Therefore, to balance the total charge, 8H⁺ must be added to the reactant side.
⇒ MnO₄⁻ + 5e⁻ + 8H⁺ → Mn²⁺
To balance the number of hydrogen and oxygen atoms, 4H₂O must be added to the product side.
⇒ MnO₄⁻ + 5e⁻ + 8H⁺ → Mn²⁺ + 4H₂O .....equation 1
Oxidation half-reaction: SO₃²⁻ → SO₄²⁻
Oxidation state of S in SO₃²⁻ is +4 and the oxidation state of S in SO₄²⁻ is +6. Therefore, S loses 2e⁻ to get oxidized from +4 to +6 oxidation state.
⇒ SO₃²⁻ → SO₄²⁻ + 2e⁻
Now the total charge on reactant side is (-2) and the total charge on product side is (-4). Therefore, to balance the total charge, 2H⁺ must be added to the product side.
⇒ SO₃²⁻ → SO₄²⁻ + 2e⁻ + 2H⁺
To balance the number of hydrogen and oxygen atoms, 1 H₂O must be added to the reactant side.
⇒ SO₃²⁻ + H₂O → SO₄²⁻ + 2e⁻ + 2H⁺ .....equation 2
Now, to cancel the electrons transferred, equation (1) is multiplied by 2 and equation (2) is multiplied by 5.
Balanced Reduction half-reaction:
MnO₄⁻ + 5e⁻ + 8H⁺ → Mn²⁺ + 4H₂O ] × 2
⇒ 2MnO₄⁻ + 10e⁻ + 16H⁺ → 2Mn²⁺ + 8H₂O .....equation 3
Balanced Oxidation half-reaction:
SO₃²⁻ + H₂O → SO₄²⁻ + 2e⁻ + 2H⁺ ] × 5
⇒ 5SO₃²⁻ + 5H₂O → 5SO₄²⁻ + 10e⁻ + 10H⁺ .....equation 4
Now adding equation 3 and 4, to obtain the overall balanced redox reaction:
2MnO₄⁻ + 5SO₃²⁻ + 6H⁺ → 2Mn²⁺ + 5SO₄²⁻ + 3H₂O
Therefore, the coefficients should be: 2, 5, 2, 5
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
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.
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 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
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
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.
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.
It turns out that the van der Waals constant b equals four times the total volume actually occupied by the molecules of a mole of gas.
Using this figure, calculate the fraction of the volume in a container actually occupied by Ar atoms at 230 atm pressure and 0 C. Assume b=0.0322 L/mol
The fraction of the volume in a container actually occupied by Ar atoms at 230 atm pressure and 0 C is 92.0%. The van der Waals constant b is 0.0322 L/mol.
The van der Waals constant b is defined as four times the total volume actually occupied by the molecules of a mole of gas 1. To calculate the fraction of the volume in a container actually occupied by Ar atoms at 230 atm pressure and 0 C, we can use the following formula:
V_real = V_ideal - nb
where V_real is the real volume of the gas, V_ideal is the ideal volume of the gas, n is the number of moles of the gas, and b is the van der Waals constant. At 0 C, the ideal volume of one mole of any gas is 22.4 L 2. Therefore, the ideal volume of Ar atoms is 22.4 L/mol.
To calculate the real volume of Ar atoms, we need to know the number of moles of Ar atoms present in the container. We can use the ideal gas law to calculate the number of moles of Ar atoms:
PV = nRT
where P is the pressure, V is the volume, n is the number of moles, R is the gas constant, and T is the temperature. Substituting the given values, we get:
n = PV/RT = (230 atm * V)/(0.0821 L atm/mol K * 273 K) = 9.03 V
Substituting the values of n and b into the formula for V_real, we get:
V_real = V_ideal - nb = 22.4 L/mol - 0.0322 L/mol * 4 * 9.03 mol = 20.6 L
Therefore, the fraction of the volume in a container actually occupied by Ar atoms at 230 atm pressure and 0 C is:
(V_real/V) * 100% = (20.6 L/V) * 100% = 92.0%
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.
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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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.
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
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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