Answer:
c
Explanation:
Write the chemical reaction that is responsible for the ph of a buffer which contains nh3 and nh4cl. write the reaction in such a way that is appropriate for a ka.
The pH of a buffer containing NH3 and NH4Cl is determined by the equilibrium between NH4+ and NH3 in water, with the reaction NH4+ (aq) + H2O(l) → H3O+ (aq) + NH3(aq). The reaction demonstrates the action of the ammonium ion as a weak acid, and its Ka is calculated using the Ka = Kw/Kb relationship. The chloride ion does not undergo significant hydrolysis, so it does not affect the pH of the buffer.
Explanation:The chemical reaction responsible for the pH of a buffer containing NH3 (ammonia) and NH4Cl (ammonium chloride) involves the equilibrium between NH4+ and NH3 in water:
NH4+ (aq) + H2O(l) ⇒ H3O+ (aq) + NH3(aq)
This represents the dissociation of the ammonium ion, which is a weak acid, in water to produce hydronium ions (H3O+) and ammonia. Since ammonia is a weak base, the corresponding acid dissociation constant (Ka) can be calculated using the relation Ka = Kw/Kb, where Kw is the ion product of water and Kb is the base dissociation constant of ammonia.
The chloride ion, being the conjugate base of the strong acid hydrochloric acid (HCl), does not undergo significant hydrolysis in water:
Cl-(aq) + H2O(l) → HCl(aq) + OH−(aq)
Since HCl is a strong acid, the equilibrium constant (Ka) for its conjugate base, Cl-, is essentially zero, which means Cl- does not affect the buffer solution's pH appreciably.
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Hexanal would be soluble in water? True or false?
Answer:
False.
Explanation:
Hexanal is a non-polar compound while water is a polar solvent.
We have the role "Like dissolves like".
So, hexanal is insoluble in water.
What mass of potassium hydroxide is formed when 8.2 g of potassium oxide is added to 1.3 g of water? answer key?
The thermal decomposition of phosphine (ph3) into phosphorus and molecular hydrogen is a first-order reaction: 4ph3(g) → p(g) + 6h2(g) the half-life of the reaction is 35.0 s at 680°c. calculate the first-order rate constant for the reaction:
The first-order rate constant for the thermal decomposition of phosphine can be calculated using the relationship between the half-life and the rate constant, resulting in a rate constant of 0.0198 s⁻¹.
The thermal decomposition of phosphine (PH₃) into phosphorus and molecular hydrogen is given as a first-order reaction, and the provided half-life of the reaction is 35.0 seconds at 680°C. To calculate the first-order rate constant for the reaction, we can use the relationship that for a first-order reaction, the half-life (t₁/2) is related to the rate constant (k) by the equation t₁/2 = ln(2) / k. Therefore, we can rearrange this formula to solve for k: k = ln(2) / t₁/2.
By plugging the values into the formula, we can calculate the rate constant as follows:
k = ln(2) / 35.0 s
k = 0.0198 s⁻¹
This is the rate constant for the first-order thermal decomposition of phosphine at the specified temperature.
The reaction of 0.779 g K with O2 forms 1.417 g potassium superoxide, a substance used in self-contained breathing devices. Determine the formula for potassium superoxide.
Final answer:
The correct formula for potassium superoxide formed when 0.779 g of potassium reacts with an excess of oxygen to form 1.417 g of the compound is[tex]KO_{2}[/tex]
Explanation:
The formula for potassium superoxide can be determined by considering the mass of potassium reacted and the mass of the resultant compound formed. In this case, 0.779 grams of potassium reacts with oxygen to form 1.417 grams of potassium superoxide. Knowing that the potassium has fully reacted and become part of the potassium superoxide, we can deduce that the difference in mass (1.417 g - 0.779 g = 0.638 g) must be due to the oxygen present in the compound.
The simplest ratio between potassium (K) and oxygen (O) that could form a compound would be a 1:1 ratio, which gives us KO. However, based on the provided information, potassium superoxide has a different stoichiometry where 1 mol of potassium reacts with oxygen to form a compound with the formula [tex]KO_{2}[/tex], which is a superoxide. This means there are two oxygen atoms for every potassium atom in the compound.
Therefore, the correct formula for potassium superoxide, as formed in the reaction with an excess of oxygen, is [tex]KO_{2}[/tex].
The activation energy for the gas phase isomerization of cyclopropane is 272 kJ. (CH2)3CH3CH=CH2 The rate constant at 718 K is 2.30×10-5 /s. The rate constant will be /s at 753 K.
In a molecule of methane (ch4), what type of bond joins the carbon atom to each of the hydrogen atoms?
The amount of water that evaporates from earth is
Answer:
The amount of water that evaporates from the earth is approximately equal to the amount that falls as precipitation.
Explanation:
Water evaporation is critical to climate because it is directly related to precipitation formation. Water that evaporates from rivers, lakes, oceans and even our bodies helps to form rain. This occurs when the temperature cools. Under these climatic conditions, water vapor returns to its liquid form (condensation) and falls through rainfall. The amount of water evaporated is basically equal to the amount of water that comes back to land in precipitation.
for the complete combustion of 5.6dm3 of a gaseuos hydrocarbon CxHy. 28.0dm3 of oxygen gas were used, 16.8dm3 of CO2 gas and 18.0gof liquid water were produced all gases measurement were made at stp. Determine the chemical formula of the hydrocarbon
Consider the reaction caso4(s)⇌ca2+(aq)+so2−4(aq) at 25 ∘c the equilibrium constant is kc=2.4×10−5 for this reaction.if excess caso4(s) is mixed with water at 25 ∘c to produce a saturated solution of caso4, what is the equilibrium concentration of ca2+?
If you dilute 13.0 ml of the stock solution to a final volume of 0.260 l , what will be the concentration of the diluted solution?
The final concentration (C_2) is 20 times less than the initial concentration (C_1), illustrating a dilution factor of 20. For instance, if C_1 were 2 mol/L, C_2 would be 0.1 mol/L.
Calculate the concentration of the diluted solution:
1. Identify the given information:
Initial volume of stock solution (V_1) = 13.0 mL
Final volume of diluted solution (V_2) = 0.260 L = 260 mL
Initial concentration of stock solution (C_1) is unknown (this is what we need to find)
2. Understand the key concept:
When a solution is diluted, the amount of solute (the substance dissolved in the solution) remains constant. Only the volume of the solution changes.
This means that the product of concentration and volume before dilution is equal to the product of concentration and volume after dilution.
3. Apply the dilution formula:
The formula is C_1V_1 = C_2V_2, where:
C_1 = initial concentration
V_1 = initial volume
C_2 = final concentration
V_2 = final volume
4. Solve for the unknown concentration (C_1):
Rearrange the formula to isolate C_1: C_1 = C_2V_2 / V_1
Plug in the known values: C_1 = (unknown) * 260 mL / 13.0 mL
Simplify: C_1 = 20 * C_2
5. Interpret the result:
The final concentration (C_2) will be 20 times less than the initial concentration (C_1). This means the solution has been diluted by a factor of 20.
6. Example:
If the initial concentration (C_1) was 2 mol/L, then the final concentration (C_2) would be 0.1 mol/L (20 times less).
He definition "'oxygen' means an element having an atomic weight of 8 and an atomic number of 16" is an example of:
Final answer:
Oxygen has three stable isotopes, 16O, 17O, and 18O, all of which have 8 protons but vary in their number of neutrons—8, 9, and 10, respectively. These variances in neutron count alter the atomic mass of the isotopes without affecting their atomic number or chemical properties.
Explanation:
The statement "Oxygen, whose atomic number is eight, has three stable isotopes: 16O, 17O, and 18O" refers to the different forms of the element oxygen which vary in the number of neutrons contained within the nucleus. The atomic number of an element indicates the number of protons within the nucleus; for oxygen, this is always eight. However, the number of neutrons can differ, changing the mass number but not the chemical properties of the element.
For each isotope of oxygen:
16O: 8 protons + 8 neutrons = 16 total nucleons
17O: 8 protons + 9 neutrons = 17 total nucleons
18O: 8 protons + 10 neutrons = 18 total nucleons
These isotopes determine the total number of nucleons (protons plus neutrons) in the atom's nucleus, represented by the mass number (A). Using the formula A - Z (where A is the mass number and Z is the atomic number), we can calculate the number of neutrons: 16O has 8 neutrons, 17O has 9 neutrons, and 18O has 10 neutrons. Isotopes of an element share the same atomic number but differ in the mass number. Oxygen's most abundant isotope is 16O, making up 99.76% of naturally occurring oxygen.
Give the characteristic of a first order reaction having only one reactant. give the characteristic of a first order reaction having only one reactant. the rate of the reaction is proportional to the square root of the concentration of the reactant. the rate of the reaction is proportional to the square of the concentration of the reactant. the rate of the reaction is directly proportional to the concentration of the reactant. the rate of the reaction is proportional to the natural logarithm of the concentration of the reactant. the rate of the reaction is not proportional to the concentration of the reactant.
Answer:
The rate of the reaction is directly proportional to the concentration of the reactant.
Explanation:
Let's consider a reaction of the kind A → B.
A general rate law has the following form:
r = k . [A]ⁿ
where,
r: reaction rate
k: reaction constant
[A]: molar concentration of the reactant A
n: order of reaction for A
For a first-order reaction, the rate law is:
r = k . [A]
Give the characteristic of a first-order reaction having only one reactant.
The rate of the reaction is proportional to the square root of the concentration of the reactant. NO. This would happen if n = 1/2.
The rate of the reaction is proportional to the square of the concentration of the reactant. NO. This would happen if n = 2
The rate of the reaction is directly proportional to the concentration of the reactant. YES.
The rate of the reaction is proportional to the natural logarithm of the concentration of the reactant. NO. This could never happen.
The rate of the reaction is not proportional to the concentration of the reactant. NO. This would happen if n = 0.
The characteristic of a first order reaction having only one reactant is that the rate of the reaction is directly proportional to the concentration of the reactant.
What is first order reaction?First order reactions are those reactions in which rate of the chemical reaction will depends on the concentration of the only reactant of the reaction.
Suppose a chemical reaction in which reactant A will form product B as:
A → B
So, Rate of the reaction is directly depends on the concentration of the A reactant.
Hence, option (3) is correct.
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Which of the following is a large body in space that orbits a star and does not produce its own light?
Moon
Planet
Sun
Universe
Calculate the vapor pressure at 50°c of a coolant solution that is 54.0:46.0 ethylene glycol-to-water by volume. at 50.0°c, the density of water is 0.9880 g/ml, and its vapor pressure is 92 torr. the vapor pressure of ethylene glycol is less than 1 torr at 50.0°c.
How many grams nano3 add to 500g of h20 prepare solution .5 molal nano3?
The activation energy for the gas phase decomposition of 2-bromopropane is 212 kJ.
CH3CHBrCH3CH3CH=CH2 + HBr
The rate constant at 683 K is 6.06×10-4 /s. The rate constant will be 5.06×10-3 /s at
The activation energy can be determined using the Arrhenius equation. To find the activation energy at a different temperature, rearrange the equation and plug in the given rate constant. The frequency factor is approximately 1.529 * 10^9 /s.
Explanation:The activation energy can be determined using the Arrhenius equation:
k = Ae^(-Ea/RT)
where k is the rate constant, A is the frequency factor, Ea is the activation energy, R is the gas constant, and T is the temperature in Kelvin.
To find the activation energy at a different temperature, we can rearrange the equation as:
Ea = -ln(k/A) * RT
Using the given rate constant at 683 K and the activation energy of 212 kJ, we can calculate the frequency factor as follows:
A = k * e^(Ea/RT)
Plugging in the values:
A = (6.06×10^(-4) /s) * e^(212000 J / (8.3145 J/mol*K * 683 K))
A = 1.529 * 10^9 /s
Therefore, the frequency factor is approximately 1.529 * 10^9 /s.
The activation energy for a reaction is the minimum amount of energy required for the reaction to occur. To find the activation energy at a different temperature, we can use the Arrhenius equation. The activation energy will be 2.71 kJ/mol at the desired condition.
Explanation:The activation energy for a reaction is the minimum amount of energy required for the reaction to occur. It represents the energy barrier that the reactants must overcome before they can form products. In the given question, the activation energy for the gas phase decomposition of 2-bromopropane is 212 kJ.
To find the activation energy at a different temperature, we can use the Arrhenius equation:
k = A * e^(-Ea/RT)
where:
- k is the rate constant
- A is the frequency factor
- Ea is the activation energy
- R is the gas constant (8.314 J/(mol·K))
- T is the temperature in Kelvin
By rearranging the equation, we can solve for the activation energy at a different temperature:
Ea2 = -ln(k2/k1) * (R/T2 - R/T1)
Substituting the given values:
Ea2 = -ln(5.06x10^-3 / 6.06x10^-4) * (8.314 J/(mol·K) / 683 K - 8.314 J/(mol·K) / 298 K)
Ea2 = -ln(8.333) * (0.0122 - 0.0278) = -ln(8.333) * (-0.0156) = 0.1739 * 0.0156 = 0.00271 J/mol = 2.71 kJ/mol
Therefore, the activation energy will be 2.71 kJ/mol at the desired condition.
How many moles (of molecules or formula units) are in each sample? part a 71.66 g cf2cl2?
moves river of ice fresh water made of fallen snow snow compressed to ice This is a list of features of a(n) A) glacier. B) ice age. C) iceberg. D) continent.
The answer is A. Glacier
dentify the molecule with the highest boiling point.
CHCl3
OF2
NH3
C6H6
Answer: Option (c) is the correct answer.
Explanation:
A molecule which has hydrogen bonding will have the highest boiling point. So, out of the given options only [tex]NH_{3}[/tex] will have hydrogen bonding.
Whereas in [tex]CHCl_{3}[/tex] there will be dipole-dipole interactions and no hydrogen bonding within the molecule.
In [tex]OF_{2}[/tex] and [tex]C_{6}H_{6}[/tex], there will be dipole-dipole interaction in both the molecules.
Thus, we can conclude that [tex]NH_{3}[/tex] will have the highest boiling point.
If the molar mass of the compound in problem 1 is 110 grams/mole, what is the molecular formula? With work?
Final answer:
To find the molecular formula, calculate the empirical formula mass, divide the molar mass by this number to find a multiplier, and apply the multiplier to the subscripts in the empirical formula.
Explanation:
Finding the Molecular Formula
To determine the molecular formula of a compound for which we know the molar mass is 110 grams/mole, and have the empirical formula from problem 1, we follow these steps:
Calculate the empirical formula mass by summing the atomic masses of each element in the empirical formula.Divide the given molar mass (110 g/mol) by the empirical formula mass. This will give us a factor by which we multiply the subscripts in the empirical formula to get the molecular formula.If our factor is close to 1, the empirical formula and the molecular formula are the same. If it's a whole number or a simple fraction, multiply each subscript in the empirical formula to get the molecular formula.For example, assuming our empirical formula is CH₂ (not given in the question), we would get the empirical formula mass as 12 (for C) + 2×1 (for H) = 14 g/mol. Then, 110 g/mol divided by 14 g/mol gives us approximately 7.86, which we round to 8 since it should be a whole number. Multiplying the subscripts in CH₂ by 8 gives us C₈H₁₆ as the molecular formula.
A student is given two metal cubes that look similar. the first had an edge length of 1.05 cm and a mass of 14.32 g, while the other had an edge length of 2.66 cm and a mass of 215.3 g. how can the student determine if these two cubes of metal are the same material using only the given data?
The value densities of cube-1 and cube-2 are not at all similar which means that both the cubes are made up of different materials.
Explanation:
Mass and volume are extensive properties of the matter which change with change in the size of matter. But density is an intensive property of a matter which is independent of the size and shape of the matter.The density of the matter is given by:[tex]Density=\frac{Mass}{Volume}[/tex]
So one can compare of values of densities of two unknowns to determine whether both are materials the same or not.Given:
Two different cubes, one with an edge length of 1.05 cm and mass of 14.32 g, and the other cube have an edge length of 2.66 cm and mass of 215.3 g.
To find:
Whether two cubes are of the same material or not.
Solution:
The edge length of the cube-1 = l = 1.05 cm
The volume of cube-1 =v
[tex]v=l^3=(1.05 cm)^3=1.16 cm^3[/tex]
Th mass of cube-1 = m = 14.32 g
The density of the cube-1 =d
[tex]d=\frac{m}{v}\\d=\frac{14.32 g}{1.16 cm^3}=12.3 g/cm^3[/tex]
The edge length of the cube-2 = l' = 2,66 cm
The volume first cube-2 =v'
[tex]v'=l'^3=(2.66 cm)^3=18.8 cm^3[/tex]
Th mass of cube-2 = m = 215.3g
The density of the cube-2 =d'
[tex]d'=\frac{m'}{v'}\\d'=\frac{215.3g}{ 18.8cm^3}=11.4g/cm^3[/tex]
The value density of cube-1 is different from that of cube-2, not at all similar which means that both the cubes are made up of different materials.
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Write and balance the chemical equation for the reaction between carbon monoxide, co(g), and oxygen to form carbon dioxide, co2(g). use only integers (not fractions) and be sure to include the states of matter.
The balanced chemical equation for the reaction between carbon monoxide (CO) and oxygen (O₂) to form carbon dioxide (CO₂) is 2 CO(g) + O₂(g) → 2 CO₂(g), adhering to the law of conservation of mass.
Explanation:The reaction between carbon monoxide (CO) and oxygen (O₂) to form carbon dioxide (CO₂) can be represented by the following balanced chemical equation:
2 CO(g) + O₂(g) → 2 CO₂(g)
In balancing this equation, it is important to ensure that the number of each type of atom on the reactants side is equal to the number on the products side. Here, we have two carbon atoms and two oxygen atoms from the CO molecules and two oxygen atoms from the O₂ molecule, giving us a total of four oxygen atoms on the reactants side, which balance with the four oxygen atoms in the two CO₂ molecules on the right side of the equation.
This reaction demonstrates the law of conservation of mass, where the mass of the reactants equals the mass of the products. In this case, the coefficients used are the smallest possible whole numbers that maintain this balance.
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A Student performing this experiment mistakenly used 6.0 ml of 16 M hno3 to dissolve 0.18g of solid copper , instead of the 4.0 ml described in lab manual. What volume of 6 M naoh are required to neutralized the excess acid
Final answer:
To neutralize the excess 16 M HNO₃, 5.33 mL of 6 M NaOH is required.
Explanation:
The task is to calculate the volume of 6 M NaOH needed to neutralize excess HNO₃ used in dissolving copper. The student used 6.0 mL of 16 M HNO₃, which is 2.0 mL more than the required amount.
First, we need to find the amount of excess HNO₃ in moles, as only 4.0 mL was required. The excess volume is 6.0 mL - 4.0 mL = 2.0 mL. The moles of excess HNO₃ is calculated as 2.0 mL × 16 M / 1000 mL/L = 0.032 moles.
To neutralize the acid, we need the same number of moles of OH-. Since the NaOH is 6 M, the volume V in liters needed is calculated using the molarity equation: moles = Molarity × Volume. Thus, 0.032 moles = 6 M × V, which gives V = 0.032 moles / 6 M. So, the volume of NaOH required is 0.00533 L, or 5.33 mL.
Draw the products for the proton transfer reaction between sodium hydride and ethanol
Final answer:
Sodium hydride donates a hydride ion to ethanol, resulting in the formation of hydrogen gas and the ethoxide ion in a sodium ethoxide complex.
Explanation:
The proton transfer reaction between sodium hydride (NaH) and ethanol (CH3CH2OH) involves sodium hydride acting as a base, donating a hydride ion (H-) to the proton (H+) of the ethanol. This reaction results in the formation of hydrogen gas (H2) and the ethoxide ion (CH3CH2O-), which remains in the solution complexed with the sodium ion (Na+). The balanced equation for this reaction is NaH + CH3CH2OH → H2 + Na+ + CH3CH2O-. This reaction utilizes the hydride ion from the sodium hydride as a nucleophile that abstracts a proton from the ethanol, leading to the evolution of hydrogen gas.
Commercial grade hcl solutions are typically 39.0% (by mass) hcl in water. determine the molarity of the hcl, if the solution has a density of 1.20 g/ml.
Answer:
12.82 mol/L the molarity of the HCl.
Explanation:
Suppose in 100 grams of 39.0% (by mass) HCl in water.
Volume of solution = V
Density of the solution = d = 1.20 g/mL
Mass = Density × Volume
[tex]V=\frac{M}{d}=\frac{100 g}{1.20 g/mL}=83.33 mL = 0.08333 L[/tex]
Mass of HCl = 39.0% of 100 grams= [tex]\frac{39}{100}\times 100g=39 g[/tex]
Moles of HCl = [tex]\frac{39 g}{36.5 g/mol}=1.0685 mol[/tex]
[tex]Molarity=\frac{\text{Moles of compound}}{\text{Volume of solution (L)}}[/tex]
The molarity of the HCl = M
[tex]M=\frac{1.0685 mol}{0.0833 L}=12.82 mol/L[/tex]
12.82 mol/L the molarity of the HCl.
Answer:
The commercial grade of HCl solution having a density of 1.20 g/ml has the molarity of 12.8 M.
Explanation:
Let's take the volume of solution to be 1000 ml.
Mass of HCl = [tex]\rm density\;\times\;volume[/tex]
Mass = [tex]\rm 1.20\;\times\;1000[/tex]
Mass of HCl = 1200 g.
In 39 % of HCl,
mass of HCl = [tex]\rm 39\;\times\;1200[/tex]
mass of HCl = 468 grams.
Molarity = [tex]\rm \frac{moles}{Liter}[/tex]
Molarity = [tex]\rm \frac{468}{36.5}\;\times\;\frac{1}{liters}[/tex]
Moalrity = 12.8 moles/liter
Molarity of 39% HCl with a density of 1.20 g/ml is 12.8 M.
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The balanced equation for a hypothetical reaction is A + 5B + 6C → 3D + 3E. What is the rate law for this reaction?
Answer: [tex]Rate=k[A]^1[B]^5[C]^6[/tex]
Explanation: Rate law says that rate of a reaction is directly proportional to the concentration of the reactants each raised to a stoichiometric coefficient determined experimentally called as order.
Order of the reaction is defined as the sum of the concentration of terms on which the rate of the reaction actually depends. It is the sum of the exponents of the molar concentration in the rate law expression.
Elementary reactions are defined as the reactions for which the order of the reaction is same as its molecularity and order with respect to each reactant is equal to its stoichiometric coefficient as represented in the balanced chemical reaction.
[tex]A+5B+6C\rightarrow 3D+3E[/tex]
[tex]Rate=k[A]^1[B]^5[C]^6[/tex]
k= rate constant
1 = order with respect to A
5 = order with respect to B
6 = order with respect to C
Thus rate law is [tex]Rate=k[A]^1[B]^5[C]^6[/tex]
The ph of 0.015 m hno2 (nitrous acid) aqueous solution was measured to be 2.63. what is the value of pka of nitrous acid?
What is the acid-base equilibrium reaction between ClO– and H2O.
Minerals form from bodies of water by the process of _____. precipitation melting cooling condensation
Minerals form from water bodies by the process of [tex]\boxed{{\text{precipitation}}}[/tex].
Further Explanation:
The formation of minerals takes place in several ways. The mineral formation depends on the physical and chemical conditions. These conditions include temperature, pressure, pH, and time.
Precipitation
It is a process by which the dissolved minerals get free from water and as a result deposits are formed. It occurs when dissolved substances come out of water. Minerals form when precipitation takes place in aqueous solutions and from gaseous emissions as in case of volcanic eruptions.
Melting
The process that results in the conversion of any substance from a solid state to the liquid state is known as melting. Another term for this process is fusion.
Cooling
The process of removal of heat by lowering the temperature of any substance is known as cooling.
Condensation
This phase transition occurs when a substance is converted from its gaseous state to the liquid state. Variations in temperature and pressure are done in order to achieve this phase change.
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Answer details:
Grade: Senior School
Chapter: Phase transition
Subject: Chemistry
Keywords: minerals, precipitation, cooling, melting, condensation, pH, temperature, time, pressure, substance, phase transition, gaseous state, liquid state, heat, dissolved minerals, water bodies.