The mass of natural gas (CH₄) you need to burn to emit 269 kJ of heat is 5.38 g, expressed to three significant figures.
The combustion of methane is an exothermic reaction, meaning that it releases heat. The heat of combustion of methane is -802.3 kJ/mol, which means that 802.3 kJ of heat are released when 1 mole of methane is burned.
We can use this information to calculate the mass of methane needed to release 269 kJ of heat.
Mass of CH₄ = Heat / Heat of combustion
= 269 kJ / (-802.3 kJ/mol)
= 0.334 mol
= 5.38 g
Therefore, you need to burn 5.38 grams of methane to emit 269 kJ of heat.
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The mass of natural gas (CH4) that must be burned to emit 269 kJ of heat is 5.42 grams.
Explanation:To calculate the mass of natural gas (CH4) that must be burned to emit 269 kJ of heat, we can use the enthalpy of combustion per mole of methane. According to the given balanced chemical equation, the enthalpy change of the combustion reaction is -802.3 kJ.
From a previous similar question, we know that when 2.50 g of methane burns, 125 kJ of heat is produced. So, we can set up a proportion to find the mass of CH4 that corresponds to 269 kJ of heat:
(2.50 g methane)/(125 kJ heat) = (x)/(269 kJ heat)
Solving for x, we find that x = 5.42 g. Therefore, the mass of natural gas that must be burned to emit 269 kJ of heat is 5.42 grams (to three significant figures).
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Draw the lewis structure with the atoms arranged as hclo. include all non-bonding electronsand non-zero formal charges. do not draw cl with an expanded octet.
The Lewis structure of HClO consists of bonds from Cl to each of H and O, with Cl having 5 pairs of non-bonding electrons and O having 2 pairs.
Explanation:To create the Lewis structure for HCLO, start by counting valence electrons. Hydrogen (H) has 1, Oxygen (O) has 6, and Chlorine (Cl) has 7. This totals to 14. Next, choose the atom with the least electronegativity (Cl in this case) to be the central atom, and draw bonds to other elements. A bond to each H and O from Cl uses up 4 electrons, leaving 10. Now fill the octets of the H and O atoms.
The Lewis structure should then look like this:
H - Cl - O
With 5 pairs of non-bonding electrons around Cl and two pairs of non bonding electrons around O.
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An unknown substance has the composition of 77.87% C, 2.63% H and 55.62% O. The compound has a molar mass of 345.2 g/mole. What is the molecular formula?
Which atomic model proposed that electrons move in specific orbits around the nucleus of an atom?
Dalton’s atomic model
Thomson’s atomic model
Rutherford’s atomic model
Bohr’s atomic model
quantum atomic model
Answer: The correct answer is Bohr's atomic model.
Explanation:
For the given options:
Dalton's atomic model: This model states that every matter is made up of smallest unit known as atom.
Thomson's atomic model: He proposed a model known as plum pudding model. He considered atom to be a pudding of positive charge in which negative particles are embedded such as plum.
Rutherford's atomic model: He gave an experiment known as gold foil experiment. In his model, he concluded that in an atom, there exist a small positive charge in the center.
Bohr's atomic model: This model states that electron revolve around the nucleus in discrete orbits in an atom.
Quantum atomic model: This model determines the location of electrons in an atom in a 3-D space.
Hence, the correct answer is Bohr's atomic model.
Maple syrup has a density of 1.325 g/ml, and 100.00 g of maple syrup contains 67 mg of calcium in the form of ca2+ ions. what is the molarity of calcium in maple syrup?
The molarity of calcium in maple syrup is 33.4 M.
Explanation:To find the molarity of calcium in maple syrup, we need to first convert the given amount of calcium from milligrams to grams. Since there are 1000 milligrams in a gram, 67 mg is equal to 0.067 g. Next, we divide the mass of calcium by the density of maple syrup to find the volume of maple syrup.
Volume of maple syrup = mass of calcium / density of maple syrup = 0.067 g / 1.325 g/ml = 0.0506 ml
Now, we can calculate the molarity of calcium (Ca2+) in maple syrup by dividing the moles of calcium by the volume of maple syrup in liters:
Molarity = moles of calcium / volume of maple syrup = (0.067 g / 40.08 g/mol) / (0.0506 ml / 1000 ml/L) = 33.4 M
Which of the following is the best definition of a chemical change?
Answer: A change in a substance where one or more new substances form
Explanation: Apex
To learn more about the genetic material of plant and animal cells, where would a person look?
A.in the lysosomes
B.in the nucleus
C.inside the chloroplasts
D.on the cell wall
Consider the following equilibrium:
4KO2(s) + 2H2O(g) 4KOH(s) + 3O2(g)
Which of the following is a correct equilibrium expression?
Keq=[KOH]4[O2]3[KO2]4[H2O]2
Keq=[H2O]2[O2]3
Keq=[KO2]4[H2O]2[KOH]4[O2]3
Keq=[O2]3[H2O]2
Answer:
[tex]Keq=\frac{[O_{2}]^{3} }{[H_{2}O]^{2} }[/tex]
Explanation:
The equilibrium constant (Keq) is equal to the product of the concentrations of the products raised to their stoichiometric coefficients divided by the product of the concentrations of the reactants raised to their stoichiometric coefficients. In Keq we include gases and aqueous species, but not solids nor pure liquids because their concentration remains almost constant over time.
Let's consider the following reaction.
4 KO₂(s) + 2 H₂O(g) ⇄ 4 KOH(s) + 3 O₂(g)
Then, the equilibrium constant is:
[tex]Keq=\frac{[O_{2}]^{3} }{[H_{2}O]^{2} }[/tex]
What is the difference between traits and characteristics?
A Characteristic is the unique assets, talents, and qualities of a person. On the other hand, a trait is a feature of a person that is hereditary or inherited from parents or offspring. The characteristics are usually something that a person can learn and built by absorption, a trait, on the other hand, is something you have since birth.
Answer:
the person on top is correct
Explanation:
6. The illustration below represents the Grand Canyon..
A mixture is two or more substances that are mixed together but not chemically combined. The substances in a mixture each keep their own properties and can be separated from the mixture.
Identify the substance in a mixture of sand, salt, sawdust, and iron filings that can easily be separated by dissolving the mixture in water.
A) sand
B) salt
C) sawdust
D) iron filings
Plz help!
When a collision occurs between two reactant particles that, between them, have the required minimum kinetic energy, or activation energy, a product does not always form. Which of the following reasons explains this?
a.low temperature
b.small surface area
c.unfavorable geometry
d.low concentration
c.unfavorable geometry
Answer: C. Unfavorable geometry
Explanation: When collision occurs between two reactants in order to make a reaction possible there are 3 factors which are responsible.
a) Orientation factor
b) Energy factor
c) rate of collision
Thus out of the given options, unfavorable geometry is the correct one as temperature and concentration as well as surface area will have very little effect on the reaction.
If the geometry of the reactant is not complementary then the reaction would not lead successfully.
The decomposition of hi has a rate constant of 1.80 × 10-3 m-1s-1. how much hi remains after 8.50 min if the initial concentration of hi is 4.78 m?
If the δh°soln of hno3 is –33.3 kj/mol, then how much heat is evolved by dissolving 0.150 mol hno3 in 100.0 ml of water?
By using the equation q = nΔH, where 'q' is the heat evolved or absorbed, 'n' is the number of moles, and 'ΔH' is the enthalpy change per mole, it is calculated that 5.0 kJ of heat is evolved when 0.150 mol of HNO3 is dissolved in 100.0 ml of water.
Explanation:The amount of heat released or absorbed in a reaction is typically calculated using the equation q = nΔH, where 'q' is the heat evolved or absorbed, 'n' is the number of moles, and 'ΔH' is the enthalpy change per mole. Given that the enthalpy of dissolving HNO3, ΔH°soln, is -33.3 kJ/mol, and we are dissolving 0.150 mol HNO3, we can substitute these values into the equation.
So, q = nΔH = 0.150 mol * -33.3 kJ/mol = -5.0 kJ.
The negative sign indicates that the heat is evolved (released), as per the question. Thus, 5.0 kJ of heat is evolved by dissolving 0.150 mol HNO3 in 100.0 ml of water.
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When 0.150 mol of HNO3 is dissolved in 100.0 ml of water, 5 kJ of heat is released. This is calculated using the equation q = n x δh°soln over the negative valence of the enthalpy change -33.3 KJ/mol.
Explanation:The amount of heat evolved from dissolving a substance in solution can be found using the equation q = n x δh°soln, where q is the heat evolved, n is the number of moles, and δh°soln is the enthalpy change per mole of solute. In this case, you have been given the enthalpy change per mole of HNO3 (δh°soln) as -33.3 kJ/mol, and the number of moles (n) as 0.150 mol. Plugging these into the equation gives q = 0.150 mol x -33.3 kJ/mol = -5 kj. This means that 5 kJ of heat is released when 0.150 mol of HNO3 is dissolved in 100.0 ml of water.
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2no2(g)⇌n2o4(g) kp=6.7at298k a 2.35-l container contains 0.053 mol of no2 and 0.084 mol of n2o4at298k. is the reaction at equilibrium? if not, in what direction will the reaction proceed?
Q> K hence the reaction proceeds in the reverse direction.
First we must obtain the concentration of each of the species;
NO2 - 0.053 mol/2.35-l = 0.023 M
N2O4 - 0.084 mol/2.35-l = 0.036 M
Hence;
Q = [N204]/[NO2]^2
Q = [0.036]/[0.023]^2
Q = 68.05
Since Q > K, it follows that the reaction moves towards the left hand side.
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The reaction quotient Q was found to be 69.86, which is greater than the equilibrium constant Kp of 6.7. Therefore, the reaction will shift towards the formation of NO2 (g) to reach equilibrium.
Explanation:To determine whether the reaction is at equilibrium, we need to calculate the reaction quotient (Qp) and compare it with the given equilibrium constant (Kp). The reaction we are analyzing is:
2 NO2 (g) ⇌ N2O4 (g), with Kp = 6.7 at 298 K.
The reaction quotient Qp is defined similarly to Kp but for an initial or non-equilibrium state and is calculated using partial pressures. Since we are given the number of moles and the volume of the container, we can use the ideal gas law to find the partial pressures of NO2 and N2O4. However, the student question provides moles instead of partial pressures, so we will assume ideal gas behavior and calculate the reaction quotient (Q) with concentrations, which can be used in place of Qp for our rough estimation, knowing they are related in the circumstance of gasses at same temperature and pressure.
The molar concentrations are:
Now we calculate the reaction quotient Q using the given concentrations:
Q = [N2O4]1 / [NO2]2
= 0.0357 / (0.0226)2
= 0.0357 / 0.000511
= 69.86
Since Q (69.86) is greater than Kp (6.7), the reaction will proceed in the direction that reduces Q to equal Kp, which is towards the formation of NO2 from N2O4.
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The nucleus of the atom contains what subatomic particle(s)? Protons only Neutrons only Electrons only Protons and neutrons Protons and electrons
Answer:
c
Explanation:
Radon (rn) is the heaviest and the only radioactive member of group 8a(18), the noble gases. it is a product of the disintegration of heavier radioactive nuclei found in minute concentrations in many common rocks used for building and construction. in recent years, health concerns about the cancers caused from inhaled residential radon have grown. if 1.00 × 1015 atoms of radium (ra) produce an average of 1.373 × 104 atoms of rn per second, how many liters of rn, measured at stp, are produced per day by 9.64 g of ra?
The amount of Rn produced per day by 9.64 g of Ra is 1.13 [tex]\rm \times\;10^-^8[/tex] L.
Moles of Radon (Ra) in 9.64 g of Ra are;
Moles = [tex]\rm \dfrac{weight}{molecular\;weight}[/tex]
Moles of Ra = [tex]\rm \dfrac{9.64}{226}[/tex]
Moles of Ra = 0.0426
Number of atoms of Ra in 0.0426 moles of Ra are:
Number of atoms = moles [tex]\times[/tex] Avagadro number
= 0.426 [tex]\times\;6.203\;\times\;10^2^3[/tex]
number of atoms of Ra produced by 9.64 g of Ra are 2.56 [tex]\rm \times\;10^2^3[/tex]
the proportion of atoms : atom\sec will be:
[tex]\rm \dfrac{atoms\;of\;Ra}{atoms\;of\;Ra/sec}\;=\;\dfrac{atoms\;of\;Rn}{x}[/tex]
[tex]\rm \dfrac{1\;\times\;10^1^5}{1.373\;\times\;10^4}\;=\;\dfrac{2.56\;\times\;10^2^2}{x}[/tex]
Atoms of Rn produced per second are 3.53 [tex]\rn \times\;10^1^0[/tex] atoms/sec.
Moles of Rn produced = [tex]\rm \dfrac{atoms\;per\;sec}{avagadro\;number}[/tex]
Moles of Rn produced = [tex]\rm \dfrac{3.52\;\times\;10^1^0}{6.023\;\times\;10^2^3}[/tex] moles
Moles of Rn produced = 5.85 [tex]\rm \times\;10^-^1^4[/tex] mol/sec.
From the ideal gas equation,
PV = nRT
The volume of Rn produced = [tex]\rm \dfrac{nRT}{P}[/tex]
= [tex]\rm \dfrac{5.85\;\times\;10^-^1^4\;\times\;0.0821\;\times\;273.15}{1}[/tex]
= 1.31 [tex]\rm \times\;10^-^1^3[/tex] liter/sec.
The amount of Rn produced per day = amount produced per second [tex]\times[/tex] 3600
The amount of Rn produced per day = 1.31 [tex]\rm \times\;10^-^1^3[/tex] [tex]\times[/tex] 24 [tex]\times[/tex] 3600 L
The amount of Rn produced per day by 9.64 g of Ra is 1.13 [tex]\rm \times\;10^-^8[/tex] L.
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The equation below shows hydrogen reacting with oxygen to produce water. 2H2+O2>2H2O if 16mol of oxygen were reacted with excess hydrogen gas, how many moles of water would be produced?
Answer : The number of moles of water produced would be, 32 moles.
Explanation : Given,
Moles of [tex]O_2[/tex] = 16 mole
The given chemical reaction is:
[tex]2H_2+O_2\rightarrow 2H_2O[/tex]
From the balanced chemical reaction we conclude that,
As, 1 mole of [tex]O_2[/tex] gas react to give 2 moles of [tex]H_2O[/tex]
So, 16 mole of [tex]O_2[/tex] gas react to give [tex]16\times 2=32[/tex] moles of [tex]H_2O[/tex]
Thus, the number of moles of water produced would be, 32 moles.
When hydrogen is burned, it reacts with oxygen and produces _____. carbon dioxide water oil helium
Calculate the freezing point of a solution containing 15 grams of kcl and 1650.0 grams of water. the molal-freezing-point-depression constant (kf) for water is 1.86 ∘c/m
Answer : The freezing point of a solution is [tex]-0.454^oC[/tex]
Explanation : Given,
Molal-freezing-point-depression constant [tex](K_f)[/tex] for water = [tex]1.86^oC/m[/tex]
Mass of KCl (solute) = 15 g
Mass of water (solvent) = 1650.0 g = 1.650 kg
Molar mass of KCl = 74.5 g/mole
Formula used :
[tex]\Delta T_f=i\times K_f\times m\\\\T^o-T_s=i\times K_f\times\frac{\text{Mass of KCl}}{\text{Molar mass of KCl}\times \text{Mass of water in Kg}}[/tex]
where,
[tex]\Delta T_f[/tex] = change in freezing point
[tex]\Delta T_s[/tex] = freezing point of solution = ?
[tex]\Delta T^o[/tex] = freezing point of water = [tex]0^oC[/tex]
i = Van't Hoff factor = 2 (for KCl electrolyte)
[tex]K_f[/tex] = freezing point constant for water = [tex]1.86^oC/m[/tex]
m = molality
Now put all the given values in this formula, we get
[tex]0^oC-T_s=2\times (1.86^oC/m)\times \frac{15g}{74.5g/mol\times 1.650kg}[/tex]
[tex]T_s=-0.454^oC[/tex]
Therefore, the freezing point of a solution is [tex]-0.454^oC[/tex]
Answer:
The freezing point of the solution containing 15 grams of KCl and 1650 grams of water is [tex]\rm -0.454^\circ\;C[/tex].
Explanation:
The freezing point of the solution can be calculated by:
Molarity = [tex]\rm \frac{mass\;of\;KCl\;}{molar\;mass\;of\;KCl\;\times\;Mass\;of\;water}[/tex]
Molarity = [tex]\rm \frac{15}{74.5;\times\;1650}[/tex]
Molarity = 1.2 [tex]\rm \times\;10^-^4[/tex] M
[tex]\rm \Delta\;T\;=\;i\;\times\;K_f\;\times\;Molarity[/tex]
[tex]\rm T^\circ\;\times\;T_f\;=\;i\;\times\;K_f\;\times\;Molarity[/tex]
[tex]\rm T_f=\;2\;\times\;1.86\;\times\;1.2\;\times\;10^-^4[/tex]
[tex]\rm T_f[/tex] = [tex]\rm -0.454^\circ\;C[/tex]
The freezing point of the solution containing KCl is [tex]\rm -0.454^\circ\;C[/tex].
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Draw the major organic product formed when the compound shown below undergoes a reaction with two equivalents of ch3ch2mgbr and then is treated with water.
The product of the reaction is 3-ethylpentan-3-ol .
What is the Grignard reagent?The Grignard reagent is a compound that is composed of an alkyl magnesium halide. Hence the general formula of a Grignard reagent is RMgX.
Since we are using two equivalents of ch3ch2mgbr and then is treat with water, the product compound is 3-ethylpentan-3-ol as shown in the image attached to this answer.
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Which of the following is the correct name for the compound MgBr2?
Magnesium bromate
Magnesium bromide
Magnesium dibromide
Magnesium (1) bromide
when the ph of a solution changes from a ph of 5 to a ph of 3 the hydronium ion concentration is
When the pH of a solution changes from 5 to 3, the hydronium ion concentration increases significantly.
PH of Solution:
The relationship between pH and hydronium ion concentration
[H₃O⁺] is given by the formula:
pH = -log [H₃O⁺]
To find the hydronium ion concentrations at pH 5 and pH 3:
At pH 5: [H₃O⁺] = 10⁻⁵ M
At pH 3: [H₃O⁺] = 10⁻³ M
Thus, the hydronium ion concentration increases by a factor of 100 when the pH changes from 5 to 3
What concentration of the barium ion, ba2+, must be exceeded to precipitate baf2 from a solution that is 1.00×10−2 m in the fluoride ion, f−? ksp for barium fluoride is 2.45×10−5 . express your answer with the appropriate units?
Answer is: concentration of the barium ion is 0.245 M.
Chemical reaction: BaF₂ → Ba²⁺ + 2F⁻.
[F⁻] = 1.00·10⁻² M.
Ksp = 2.45·10⁻⁵.
Ksp = [Ba²⁺] · [F⁻]².
[Ba²⁺] = Ksp ÷ [F⁻]².
[Ba²⁺] = 2.45·10⁻⁵ ÷ (1.00·10⁻² M)².
[Ba²⁺] = 0.245 M.
Answer: The concentration of barium ions that must exceed to precipitate the salt is 0.245 M
Explanation:
Solubility product is defined as the product of concentration of ions present in a solution each raised to the power its stoichiometric ratio. It is represented as [tex]K_{sp}[/tex]
Barium fluoride is an ionic compound formed by the combination of 1 barium ion and 2 fluoride ions.
The equilibrium reaction for the ionization of barium fluoride follows the equation:
[tex]BaF_2(s)\rightleftharpoons Ba^{2+}(aq.)+2F^-(aq.)[/tex]
The solubility product for the above reaction is:
[tex]K_{sp}=[Ba^{2+}]\times [F^-]^2[/tex]
We are given:
[tex][F^-]=1.00\times 10^{-2}M\\\\K_{sp}=2.45\times 10^{-5}[/tex]
Putting values in above equation, we get:
[tex]2.45\times 10^{-5}=[Ba^{2+}]\times (1.00\times 10^{-2})^2[/tex]
[tex][Ba^{2+}]=\frac{2.45\times 10^{-5}}{(1.00\times 10^{-2})^2}=0.245M[/tex]
Hence, the concentration of barium ions that must exceed to precipitate the salt is 0.245 M
What is true about the element Francium (Fr, atomic number 87)? choose 3
A. It has seven valence electrons
B. It is likely to form ionic bonds
C. It is a nonmetal
D. It is in period Seven
E. It is a metal
Answer :
(B) It is likely to form ionic bonds
(D) It is in period seven
(E) It is a metal
Explanation :
Francium is an element whose symbol is 'Fr' and atomic number is 87.
Group 1 alkali metals consists elements Lithium, Sodium, Potassium, Rubidium, Caesium and Francium. Periodic table also shown below.
Francium belongs to the group 1 (alkali metal) and it is in period seven.
It has one valence electron, the electronic configuration of Francium is [Rn} [tex]7s^{1}[/tex].
Alkali metals have tendency to form ionic compounds because they have +1 charge.
The correct statements about Francium (Fr, atomic number 87) are that it is likely to form ionic bonds, is in period seven, and is a metal.
Explanation:The element Francium (Fr, atomic number 87) has several characteristics based on its position in the periodic table. Firstly, as an element in Group 1, it has one valence electron which makes statement A incorrect. This single valence electron also means Francium is highly probable to form ionic bonds with nonmetals seeking to gain electrons, making statement B true. Francium is not a nonmetal, so statement C is false. Statement D is correct as Francium is located in period seven of the periodic table. Lastly, because Francium is in Group 1, it is indeed an alkali metal, making statement E true. Therefore, the correct statements about Francium are B, D, and E.
how many moles of Na3PO4 would be required to react with 1.0 mol of AgNO3?
Answer: The number of moles of sodium phosphate required is 0.33 moles
Explanation:
We are given:
Moles of silver nitrate = 1 mole
The chemical equation for the reaction of sodium phosphate and silver nitrate follows:
[tex]Na_3PO_4+3AgNO_3\rightarrow 3NaNO_3+Ag_3PO_4[/tex]
By Stoichiometry of the reaction:
3 moles of silver nitrate reacts with 1 mole of sodium phosphate.
So, 1.0 moles of silver nitrate will react with = [tex]\frac{1}{3}\times 1.0=0.33mol[/tex] of sodium phosphate.
Hence, the number of moles of sodium phosphate required is 0.33 moles
At high pressures, real gases do not behave ideally. calculate the pressure exerted by 18.0 g h2 at 20.0°c in a 1.00 l container assuming in part 1 non-ideal behavior and in part 2 ideal behavior.
Is oil used by other organisms on Earth? If yes, explain.
Vitellium (Vi) has the following composition:
Vi–188: 187.9122 amu; 10.861%
Vi–191: 190.9047 amu; 12.428%
Vi–193: 192.8938 amu; 76.711%
Based on this data, what can you predict about the average atomic mass of vitellium?
A.)It will be equal to the arithmetic mean of the masses of the three isotopes.
B.)It will be closer to the mass of Vi–188.
C.)It will be closer to the mass of Vi–193.
D.)It will be equal to the mass of Vi–193.
And I am a PLATO user so I already know it's not A!
For 520.0 ml of a buffer solution that is 0.175 m in hc2h3o2 and 0.165 m in nac2h3o2, calculate the initial ph and the final ph after adding 0.020 mol of hcl.
Sam wants to demonstrate how water changes from a solid to a gas. He places ice in a pot on a stove. What variable is causing water to change state?
A) the heat from the stove
B) the container the ice is placed in
C) the temperature of the air surrounding the ice
D) the time that has lapsed since the ice was removed from the freezer
Answer: Option (A) is the correct answer.
Explanation:
When Sam placed ice in a pot on a stove then there will be transfer of heat from the stove to the pot and then from the pot to the ice.
As a result, solid state of ice changes into liquid state of water because of melting of ice.
Thus, we can conclude that the heat from the stove is the variable that is causing water to change state.