Final answer:
The difference between ΔHrxn and ΔHf lies in their application; ΔHrxn measures the energy change in a reaction, while ΔHf pertains to the formation of a compound from its elements. The change in enthalpy per mole of a reaction is demonstrated experimentally through methods like calorimetry, which measures temperature changes.
Explanation:
Fundamentally, ΔHrxn and ΔHf differ in their application within thermodynamics. ΔHrxn, or the enthalpy change for a reaction, measures the overall energy change when reactants turn into products under constant pressure. This encompasses the total heat absorbed or released, calculated as the difference between the enthalpy of products and reactants. In contrast, ΔHf, or the standard enthalpy of formation, is the enthalpy change accompanying the formation of 1 mole of a substance from its elements in their most stable states, under standard conditions (1 bar, 298.15 K).
The part of the experiment that demonstrates the change in enthalpy per mole of a reaction typically involves measuring the temperature change of the surroundings or the system itself during a chemical reaction. This temperature change, coupled with the specific heat capacity of the system and the number of moles of reactants or products, allows us to calculate the enthalpy change. Therefore, experimental methods such as calorimetry can directly measure the enthalpy changes, providing insights into whether a reaction is endothermic or exothermic based on the ΔH values calculated.
The mole fraction of iodine, i2, dissolved in dichloromethane, ch2cl2, is 0.115. what is the molal concentration, m, of iodine in this solution?
If the ph of a 1.00-in. rainfall over 1600 miles2 is 3.60, how many kilograms of sulfuric acid, h2so4, are present, assuming that it is the only acid contributing to the ph? for sulfuric acid, ka1 is very large and ka2 is 0.012.
Write a chemical equation depicting what happens to the salt in water.
Convert the pressure 0.840 atm to mm Hg
The pressure of 0.840 atmospheres (atm) can be converted to millimeters of mercury (mm Hg) by using the conversion factor, 1 atm = 760 mm Hg. The result of this conversion is 638.4 mm Hg.
Explanation:To convert the pressure from atmospheres (atm) to millimeters of mercury (mm Hg), we use the conversion factor of 1 atm = 760 mm Hg. This is a known standard in chemistry and physics. In this case, the conversion will be as follows:
0.840 atm x 760 mm Hg/1 atm = 638.4 mm Hg
Therefore, 0.840 atm is equivalent to 638.4 mm Hg.
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The identity of a carbonyl-containing compound has been narrowed down to three possibilities: acetamide (ethanamide), acetone (propanone), or 1,1,1-trichloropropanone. 1h nmr and ir spectral data for the compound are given below. determine the structure, and thus the identity, of the compound that gives the observed data.
If this reaction produced 19.6 g of kcl, how much o2 was produced (in grams)?
what is 30-9x2*2-21-4+4
Write the balanced chemical equation for the reverse reaction. include physical states for all species.
The balanced equation for the reverse reaction would be
[tex]2SO_3 (g) < ----- > 2SO_2 (g) + O_2 (g)[/tex]
Reversible reactionsThey are reactions that proceed in opposing directions - that is, reactants to products and vice versa.
The equilibrium system between sulfur dioxide gas, oxygen gas, and sulfur trioxide gas can be represented as:
[tex]2SO_2 (g) + O_2 (g) < --- > 2SO_3 (g)[/tex]
Thus, the reverse reaction would be:
[tex]2SO_3 (g) < ----- > 2SO_2 (g) + O_2 (g)[/tex]
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The equilibrium system between sulfur dioxide gas, oxygen gas, and sulfur trioxide gas is given. Write the balanced chemical equation for the reverse reaction. Include physical states for all species.
What mass of phosphoric acid (h3po4, 98.0 g/mol) is produced from the reaction of 10.0 g of p4o10 (284 g/mol) with excess water?
Answer : The mass of phosphoric acid produced is 6.89 grams.
Solution : Given,
Mass of [tex]P_4O_{10}[/tex] = 10.0 g
Molar mass of [tex]P_4O_{10}[/tex] = 284 g/mole
Molar mass of [tex]H_3PO_4[/tex] = 98.0 g/mole
First we have to calculate the moles of [tex]P_4O_{10}[/tex].
[tex]\text{ Moles of }P_4O_{10}=\frac{\text{ Mass of }P_4O_{10}}{\text{ Molar mass of }P_4O_{10}}=\frac{10.0g}{284g/mole}=0.0352moles[/tex]
Now we have to calculate the moles of [tex]MgO[/tex]
The balanced chemical reaction is,
[tex]P_4O_{10}+6H_2O\rightarrow 4H_3PO_4[/tex]
From the reaction, we conclude that
As, 1 mole of [tex]P_4O_{10}[/tex] react to give 2 mole of [tex]H_3PO_4[/tex]
So, 0.0352 moles of [tex]P_4O_{10}[/tex] react to give [tex]0.0352\times 2=0.0704[/tex] moles of [tex]H_3PO_4[/tex]
Now we have to calculate the mass of [tex]H_3PO_4[/tex]
[tex]\text{ Mass of }H_3PO_4=\text{ Moles of }H_3PO_4\times \text{ Molar mass of }H_3PO_4[/tex]
[tex]\text{ Mass of }H_3PO_4=(0.0704moles)\times (98.0g/mole)=6.89g[/tex]
Therefore, the mass of phosphoric acid produced is 6.89 grams.
The ka of benzoic acid is 6.4 x 10–5. what is the approximate ph of a 1.5 m solution of benzoic acid?
Answer: 2.01
Explanation:
[tex]C_6H_5COOH\rightleftharpoons C_6H_5COO^-+H^+[/tex]
initial : c 0 0
eqm: [tex]c(1-\alpha)[/tex] [tex]c\alpha[/tex] [tex]c\alpha[/tex]
[tex]K_a=\frac{c\alpha\times c\alpha}{c(1-\alpha)}[/tex]
when [tex]\alpha[/tex] is very very small the, the expression will be,
[tex]k_a=\frac{c^2\alpha^2}{c}=c\alpha^2\\\\\alpha=\sqrt{\frac{k_a}{c}}[/tex]
And,
[tex][H^+]=c\alpha[/tex]
Thus the expression will be,
[tex][H^+]=\sqrt{k_a\times c}[/tex]
Now put all the given values in this expression, we get
[tex][H^+]=\sqrt{(6.4\times 10^{-5})\times 1.5}[/tex]
[tex][H^+]=9.7\times 10^{-3}M[/tex]
[tex]pH=-log[H^+][/tex]
[tex]pH=-log[9.7\times 10^{-3}]=2.01[/tex]
Which of the following would likely be part of an ionic bond? Choose all that apply.
A. K+1
B. Cl2
C. F–1
D. Ne
the answer is A and C
What is the total number of valence electrons in the lewis structure of sef2o?
The total number of valence electrons in the Lewis structure of SEF2O is calculated by adding the valence electrons of each atom, giving us a total of 26 electrons.
Explanation:The total number of valence electrons in the lewis structure of SEF2O can be calculated by adding up the valence electrons in each atom. Selenium (Se) has 6 valence electrons, each Fluorine (F) has 7 (so that's 14 for 2 Fluorines), and Oxygen (O) also has 6. So, the total number of valence electrons in SEF2O is 24+2 = 26.
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The total number of valence electrons in the Lewis structure of SeF2O is 26.
Explanation:The Lewis structure of SeF2O consists of a central Se atom bonded to two F atoms and one O atom. To determine the total number of valence electrons, we need to add up the valence electrons of each particle. She has six valence electrons, each F atom has seven valence electrons, and O has six valence electrons. Therefore, the total number of valence electrons in the Lewis structure of SeF2O is 6 (Se) + 2(7) (F) + 6 (O) = 26.
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What is the molar mass of a substance?
a. the mass in grams of one mole of a substance
b. the number of particles in one gram of a substance
c. the number of moles in one gram of a substance
d. the mass in grams of one particle of a substance
Answer: Option (a) is the correct answer.
Explanation:
Molar mass is defined as the mass in grams of one mole of a substance.
Mathematically, Molar mass = [tex]\frac{mass in grams}{moles of substance}[/tex]
For example, molar mass of 1 mole of [tex]CH_{4}[/tex] molecule will be calculated as follows.
Molar mass of [tex]CH_{4}[/tex] = [tex]mass of carbon atom + 4 \times mass of hydrogen atom[/tex]
= [tex]12 + 4 \times 1[/tex]
= 16 g
Therefore, 1 mole of [tex]CH_{4}[/tex] molecules has a molar mass of 16 g.
A tank of water contains many billions of water molecules. These molecules move at random speeds and in random directions, often colliding with each other. What form of energy does the water have due to the random motion of its particles?
thermal
radiant
chemical
potential
The energy due to the random motion of water molecules in a tank is thermal energy, which is related to the temperature of the water and can be transferred as heat.
The form of energy that water has due to the random motion of its molecules is called thermal energy. This energy arises from the kinetic energy that is present in the random microscopic motions of the water molecules. When these molecules move, collide, and bounce off each other, the average kinetic energy of these motions correlates with the temperature of the water. Furthermore, thermal energy can be transferred between objects or systems through processes like conduction, convection, and radiation, at which point it is commonly referred to as heat energy.
Write a net ionic equation for the overall reaction that occurs when aqueous solutions of phosphoric acid (h3po4) and potassium hydroxide are combined.assume excess base. use the pull-down boxes to specify states such as (aq) or (s).
After you preform your experiment, you determine that the kf value for naphthalene is 6.91 °c/m . you are using 10g of naphthalene and added 1.0 g of your unknown. the the freezing point of the solvent decreased by 4.47 °c when the unknown was added. knowing this information, determine the molar mass of the unknown. g/mol
Based on the Kf value and mass of the solvent naphthalene, the molar mass of the unknown compound is 154.58 g/mol.
What is the molar mass of a substance?The molar mass of a substance is the mass of one mole of that substance.
The molar mass of a substance can be calculated from the Kf value and mass of the solvent naphthalene as follows:
mass of naphthalene = 10 g or 0.01 kg.
mass of unknown compound = 1.00 g
ΔT of the solution = 4,47 °C.
Kf value of naphthalene = 6.91°C/m;
Molar mass of unknown compound = Kf(naphthalene) × mass of unknown compound/ mass of naphthalene × ΔTMolar mass of the unknown compound = 6.91°C/m · 1 g ÷ 0.01 kg × 4,47°C.
Molar mass of the unknown compound = 154.58 g/mol.
Therefore, the molar mass of the unknown compound is 154.58 g/mol.
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Match the element or group to the rule assigning its oxidation state.
(1.5 points) A. Oxygen B. Hydrogen C. Lone elements and atoms in gases D. Elements with multiple oxidation states E. Elements in groups 1, 2, and 17 and polyatomic ions
_____ 0
_____ Ionic charge
_____ +1, – 1 if bonded to a diatomic metal
_____ Almost always –2
_____ Determined by other elements in the compound
C. Lone elements and atoms in gases : 0
Elements in the free elemental have an oxidation number of zero
E. Elements in groups 1, 2, and 17 and polyatomic ions : Ionic charge
Group 1, 2, and 17 ions are formed by the alkali metals, alkaline metals and halogens respectively. Alkali metals, alkaline metals and halogens form +1, +2 and -1 ions respectively. Polyatiomic ions have -1, -2, -3 charges such as OH-, CO32-, PO43- respectively.
B. Hydrogen : +1, – 1 if bonded to a diatomic metal
H has an oxidation number of +1. H in metal hydrides such as NaH (sodium hydride) has an oxidation number of -1
A. Oxygen : Almost always –2
O has an oxidation number of -2.
D. Elements with multiple oxidation states : Determined by other elements in the compound
V (vanadium) has different oxidation which depends on the compound in which V is found.
look at the thing attached
The wittig reaction involves coupling between a phosphonium ylide and a carbonyl-containing molecule. if a chemist wants to use the wittig reaction to synthesize 2-methyl-2-pentene, which reactants should be used?
In the Wittig reaction to synthesize 2-methyl-2-pentene, a phosphonium ylide and a carbonyl-containing molecule, such as an aldehyde or a ketone, are needed as reactants.
Explanation:The reactants needed for the Wittig reaction to synthesize 2-methyl-2-pentene are a phosphonium ylide and a carbonyl-containing molecule. In this case, the carbonyl-containing molecule should be an aldehyde or a ketone. The phosphonium ylide is usually generated from a phosphine and an alkyl halide. For example, one possible combination of reactants could be triphenylphosphine and methyl iodide to form the phosphonium ylide, which can then react with an aldehyde or ketone to produce 2-methyl-2-pentene.
What is the pressure in atmospheres if 1360.0g of N2O gas is compressed in a 25.0L cylinder and is stored in an outdoor shed where the temperature can reach 59.0°C in the summer?
Final answer:
pressure of 34.19 atmospheres.
Explanation:
To find the pressure in atmospheres of 1360.0g of N2O gas compressed in a 25.0L cylinder at 59.0°C, use the Ideal Gas Law PV = nRT, where:
P is the pressure we want to find, V is the volume of the gas (25.0L),n is the number of moles of N2O,R is the ideal gas constant (0.0821 L·atm/K·mol),T is the temperature in Kelvin (59.0°C + 273.15 = 332.15 K).First, calculate the moles of N2O:
Molecular mass of N2O = (14.0×2) + 16.0 = 44.0g/mol
Moles of N2O = 1360.0g / 44.0g/mol = 30.91mol
Then, substitute the values into the Ideal Gas Law and solve for P:
P = (nRT)/V = (30.91mol × 0.0821 L·atm/K·mol × 332.15 K) / 25.0L = 34.19 atm
I NEED HELP, HELP ME PLZ!!!
Use the equation. How much SiCl4 is needed to produce 2.7 moles HCl?
SiCl4 + 4 H2O --> H4SiO4 + 4 HCl
How many grams of CaCl2 must be used to provide 0.252 moles of chloride ions?
To provide 0.252 moles of chloride ions, one would need 13.98428 grams of [tex]CaCl_2[/tex], using its molar mass of 110.98 g/mol and factoring in that each mole of [tex]CaCl_2[/tex] contains two moles of chloride ions.
To find out how many grams of calcium chloride ([tex]CaCl_2[/tex]) must be used to provide 0.252 moles of chloride ions, consider that each mole of [tex]CaCl_2[/tex] contains two moles of chloride ions. The molar mass of [tex]CaCl_2[/tex] is 110.98 g/mol.
To get the total number of moles of [tex]CaCl_2[/tex] needed, halve the number of chloride ions, which is [tex]\frac{0.252 moles}{2} = 0.126 moles[/tex] [tex]CaCl_2[/tex]. Then, use the molar mass to convert moles to grams:
0.126 moles [tex]CaCl_2[/tex] x 110.98 g/mol = 13.98428 grams of [tex]CaCl_2[/tex]
Therefore, you would need 13.98428 grams of [tex]CaCl_2[/tex] to provide 0.252 moles of chloride ions.
A carbon sink is a location that stores carbon for a long period of time. What are two carbon sinks that remove carbon from the atmosphere?
Plants, the ocean, and soil serve as the primary natural carbon sinks. A portion of the carbon dioxide that plants absorb from the environment to use in photosynthesis is transferred to the soil as plants disintegrate and die.
What is carbon sinks?Anything—natural or artificial—that gathers and stores a carbon-containing chemical compound over an extended period of time eliminates carbon dioxide from the atmosphere.
The ocean and vegetation are the two most significant carbon sinks on a global scale.
Typically, forests act as carbon sinks, absorbing more carbon than they emit. Through photosynthesis, they remove carbon from the atmosphere on a constant basis.
Another example of a carbon sink is the ocean, which takes in a lot of carbon dioxide from the atmosphere.
Therefore, the ocean, plants, and soil serve as the primary natural carbon sinks.
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Complete the sentence to explain when waves interact.
Waves interact with _____ and other _______ .
The answer is: Waves interact with objects and other waves.
There are many types of waves, with different energy and interactions witt.
In order from highest to lowest energy: gamma rays, X-rays, ultraviolet radiation, visible light, infrared radiation, and radio waves.
For example, ultraviolet wave is a type of electromagnetic radiation.
Ultraviolet has shorter waves and higher energy than violet, it lies between visible light and X-rays on the electromagnetic spectrum.
Ultraviolet radiation oscillates at rates between about 800 terahertz (THz) and 30000 THz.
To effectively stop both beta particles and gamma waves, scientists use a chamber composed of lead (Pb).
Answer:
objects and waves
Explanation:
Choose the solvent below that would show the greatest freezing point lowering when used to make a 0.20 m nonelectrolyte solution.
Because the rock is irregularly shaped, you used the (______) method to measure its volume. A. Addition B. Direct C. Displacement
Answer:
Displacement
Explanation:
The concentrations of the products at equilibrium are [pcl3] = 0.180 m and [cl2] = 0.250 m. what is the concentration of the reactant, pcl5, at equilibrium?
The concentration of the reactant PCl5 at equilibrium can be found using the given equilibrium concentrations of the products and the equilibrium constant by rearranging the equilibrium expression and substituting the known values.
Explanation:To determine the concentration of the reactant PCl5 at equilibrium, we use the equilibrium constant Ke for the reaction, which is given as 0.0211. Let's set up the equilibrium expression for this decomposition reaction:
PCl5 → PCl3 + Cl2
The equilibrium constant expression is:
Ke = [PCl3][Cl2] / [PCl5]
We can rearrange this equation to solve for [PCl5]:
[PCl5] = [PCl3][Cl2] / Ke
We substitute the given concentrations [PCl3] = 0.180 M and [Cl2] = 0.250 M into the equation:
[PCl5] = (0.180 M)(0.250 M) / 0.0211
By calculating the above equation, we find the concentration of PCl5 at equilibrium.
What type of change does electron have?
Imagine a solution of two liquids that are so similar that their interactions together are the same as in the individual liquids. will this solution deviate positively from, deviate negatively from, or ideally follow raoult's law?
write complete ionic and net ionic equations for, SrCO3(s)+H2SO4(aq) -> SrSO4(s) +CO2(g)+H2O(l)