Answer:
We can for 5.93 grams potassium fluoride
Explanation:
Step 1: Data given
Mass of potassium = 4.00 grams
Mass of fluorine = 3.00 grams
Molar mass potassium = 39.10 g/mol
Molar mass fluorine gas =38.00 g/mol
Step 2: The balanced equation
2K (s) + F2 (g) → 2KF (s)
Step 3: Calculate moles potassium
Moles potassium = 4.00 grams / 39.10 g/mol
Moles potassium = 0.102 moles
Step 4: Calculate moles F2
Moles F2 = 3.00 grams / 38.00 g/mol
Moles F2 = 0.0789 moles
Step 5: Calculate limiting reactant
Potassium is the limiting reactant. There will react 0.102 moles
Fluorine gas is in excess. There will react 0.102/ 2 = 0.051 moles
There will remain 0.0789 - 0.051 = 0.0279 moles
Step 6: Calculate moles potassium fluoride
For 2 moles potassium we need 1 mol fluorine to produce 2 moles potassium fluoride
For 0.102 moles K we need 0.102 moles KF
Step 7: Calculate mass KF
Mass KF = moles KF * molar mass KF
Mass KF = 0.102 moles * 58.10 g/mol
Mass KF = 5.93 grams
Final answer:
By calculating the moles of potassium and fluorine used in the reaction from their given masses, and considering the stoichiometry of the balanced equation, it's determined that 4.59 grams of potassium fluoride can be produced.
Explanation:
The question asks how many grams of potassium fluoride can form when 4.00 grams of potassium react with 3.00 grams of fluorine gas according to the balanced chemical equation 2K (s) + F2 (g) → 2KF (s). To solve this, we first find the molar mass of potassium (K) and fluorine (F2), which are approximately 39.10 g/mol and 38.00 g/mol, respectively. Then, we calculate the moles of K and F2 available by dividing the given masses by their respective molar masses. With potassium: 4.00 g / 39.10 g/mol = 0.102 moles of K; with fluorine: 3.00 g / 38.00 g/mol = 0.079 moles of F2. As the equation shows a 2:1 ratio, fluorine limits the reaction. Therefore, we can form 0.079 moles of KF. The molar mass of KF is approximately 58.10 g/mol (39.10 g/mol for K + 19.00 g/mol for F). Thus, the mass of KF that can form is 0.079 moles × 58.10 g/mol = 4.59 grams.
Balance the following equation with the smallest whole number coefficients. Choose the answer that is the sum of the coefficients in the balanced equation. Do not forget coefficients of "one". RbOH + H3PO4 → Rb3PO4 + H2O
Final answer:
To balance the equation RbOH + H3PO4 → Rb3PO4 + H2O, you use the coefficients 3, 1, 1, and 3, resulting in a sum of 8.
Explanation:
The question involves balancing a chemical equation to ensure that the same number of atoms of each element is present on both sides, following the law of conservation of mass. The balanced equation for RbOH + H3PO4 → Rb3PO4 + H2O is 3RbOH + H3PO4 → Rb3PO4 + 3H2O, giving us coefficients 3, 1, 1, 3, and the sum of these coefficients is 8.
It's important to never change the subscripts in a chemical formula while balancing an equation. Instead, coefficients are placed in front of the chemical formulae to indicate the relative amounts of reactants and products. The lowest whole number ratio that balances the equation should be used.
The activation energy for the reaction NO2(g)+CO(g)⟶NO(g)+CO2(g) is Ea = 75 kJ/mol and the change in enthalpy for the reaction is ΔH = -175 kJ/mol .What is the activation energy for the reverse reaction?
Answer:
= 100kJ
Explanation:
The reverse reaction's activation energy of a reaction is the activation energy of the forward reaction plus ΔH of the reaction:
Ea of forward reaction =75kJ
∆H = -175 kJ/mol
Ea of reverse reaction = 75 +(-175)
= 100kJ
Note that a reverse reaction is one which can proceed in both direction depending on the conditions.
Final answer:
The activation energy for the reverse reaction is calculated using enthalpy change and the activation energy for the forward reaction; it is 250 kJ/mol.
Explanation:
To find the activation energy for the reverse reaction, we can utilize the relationship between the activation energy for the forward reaction (Ea forward), the activation energy for the reverse reaction (Ea reverse), and the enthalpy change (ΔH) of the reaction. The activation energy for a reaction in one direction plus the activation energy for the reverse reaction is equal to the enthalpy change (ΔH) of the overall reaction. Using the given data for the forward reaction: Ea forward = 75 kJ/mol, and ΔH = -175 kJ/mol, we can calculate the activation energy for the reverse reaction using the equation:
Ea reverse = Ea forward - ΔH
Plugging the values into the equation gives:
Ea reverse = 75 kJ/mol - (-175 kJ/mol)
Ea reverse = 75 kJ/mol + 175 kJ/mol
Ea reverse = 250 kJ/mol
Therefore, the activation energy for the reverse reaction is 250 kJ/mol.
Woody plants evolve in the mid-Paleozoic Era. A. atmospheric CO2 increases B. atmospheric CO2 decreases C. There is no change in atmospheric CO2 levels.
Answer:
A. atmospheric CO2 increases
Explanation:
The concentration of CO2 during the Paleozoic era was much higher than the current one, due to geographical factors, but not the chemical composition of the air, which should have been more important in increasing this gas.
The highest concentrations of CO2 during the Paleozoic era occurred during the Cambrian, approximately 7000 ppm (18 times higher than current measurements). During the Late Ordovic Period the CO2 concentration was approximately 12 times higher than the current ones, with a value of 4400 ppm. These high concentrations of CO2 favored the plants colonizing the continents and thus affecting the world climate.
Rank the following solutes in order of increasing entropy when 0.0100 moles of each dissolve in 1.00 liter of water.
Answer:
CH3OH, NaBr, CaCl2, Cr(NO3)3
Based on disorderliness, the ionization strength gives the entropy.
CH3OH - Does not ionize, it's a solvent
NaBr- Ionizes intwo two ions
CaCl2- Ionizes to three ions 1Ca and 2 Cl ions
Cr(NO3)3- Ionizes to four ions
Explanation:
Here is the complete question:.
Rank the following solutes in order of increasing entropy when 0.0100 moles of each dissolve in 1.00 liter of water.
CaCl2, CH3OH, Cr(NO3)3, NaBr
Which will evaporate more quickly: 55 mLmL of water in a beaker with a diameter of 4.5 cmcm, or 55 mLmL of water in a dish with a diameter of 12 cmcm ?
Explanation:
More is the surface area of water comes in contact with the atmosphere or its surrounding more readily it will evaporate.
So, when 55 mL of water in a beaker with a diameter of 4.5 cm is placed then due to the small diameter of the beaker less surface area is in contact with the atmosphere.
But when 55 mL of water in a dish with a diameter of 12 cm is placed then it has larger diameter as compared to 4.5 cm diameter. Therefore, water in a beaker of 12 cm diameter will evaporate more quickly.
Thus, we can conclude that water in 55 mL of water in a dish with a diameter of 12 cm will evaporate more quickly.
The larger the surface area exposed to air, the faster the rate of evaporation. Therefore, a dish with a larger diameter will allow water to evaporate more quickly than a beaker with a smaller diameter while holding the same volume of liquid.
Explanation:The 55 mL of water will evaporate more quickly in the dish with a diameter of 12 cm. This is because evaporation is a surface phenomenon - it depends on the surface area exposed to air. In this case, the dish with a more significant diameter will have a larger surface area exposed to air, leading to faster evaporation.
An analogy might be to consider two scenarios: the first is pouring a cup of coffee into a narrow, high cylinder and the second is into a broad, low dish. Both containers might have the same volume, but the surface area is significantly different. The coffee in the broad dish is more exposed and will cool faster due to a higher degree of evaporation.
Just as the coffee cools in the broad dish, the water in the dish with the larger diameter will evaporate more quickly. While volume might be constant in both the beaker and the dish, the shape and structure of the container significantly impact the rate of evaporation.
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Increasing the temperature of the solvent ____________________ the solubility of a solid solute and _______________________ the solubility of a gases solute.
Answer:
increase in solvent temperature will increase the solubility of solid particle but decreases the solubility of gas particle.
Explanation:
In solid particle when temperature increases its help to break apart the solid particle and increase in kinetic energy of solvent results in increase in solubility of solid particles in solvent.
but in gas solute, increase in temperature of solvent causes the increase in motion of gas molecules means increase in kinetic energy of molecules in the gas which results in breakage of inter molecular bonds and removal of the molecules from the heated solution.
A compound consists of 65.45% C, 5.492% H, and 29.06% O on a mass basis and has a molar mass of 110 g/mol. Determine the molecular formula of the compound.
Answer:
The molecular formula is C6H6O2
Explanation:
Step 1: Data given
Suppose the mass of the compound = 100 grams
The compound has:
65.45 % C = 65.45 grams
5.492 % H = 5.49 grams
29.06 % O = 29.06 grams
Molar mass C = 12.01 g/mol
Molar mass H = 1.01 g/mol
Molar mass O = 16.00 g/mol
Molar mass = 110 g/mol
Step 2: Calculate moles
Moles = mass / molar mass
Moles C = 65.45 grams / 12.01 g/mol
Moles C = 5.450 moles
Moles H = 5.49 grams / 1.01 g/mol
Moles H = 5.44 moles
Moles O = 29.06 grams / 16.00 g/mol
Moles O = 1.816 moles
Step 3: Calculate mol ratio
We divide by the smallest amount of moles
Moles C = 5.450 moles / 1.816 = 3
Moles H = 5.44 moles / 1.816 = 3
Moles O = 1.816/1.816 = 1
The empirical formula is C3H3O
The molar mass of this formula is 55 g/mol
We have to multiply the empirical formula by n
n = 110/55 = 2
2*(C3H3O) = C6H6O2
The molecular formula is C6H6O2
The empirical formula for the compound, given the percentage composition and molecular mass, is C3H3O. The molecular formula, given that the molar mass of the compound is about 2.66 times the empirical formula's molar mass, is C9H9O3.
Explanation:To determine the molecular formula of the compound, we first assume that we have 100g of the compound. This means we have 65.45g of Carbon (C), 5.492g of Hydrogen (H), and 29.06g of Oxygen (O). We must then convert these masses to moles by dividing by the atomic mass (12.01 for C, 1.008 for H, and 16 for O).
Therefore, we have:
For Carbon: 65.45g ÷ 12.01g/mol = 5.45 molFor Hydrogen: 5.492g ÷ 1.008g/mol = 5.45 molFor Oxygen: 29.06g ÷ 16g/mol = 1.816 molWe then divide these mole quantities by the smallest obtained mole number to try to get whole numbers. This should give an atomic ratio of 3:3:1 for C, H, and O respectively.
By combining these ratios into a chemical formula, we get C3H3O. This is the empirical formula. The molar mass of this formula (41 g/mol) goes into the given molar mass of the compound (110 g/mol) about 2.66 times, indicating that the true molecular formula of this compound is C9H9O3.
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The _______________ system collects solid wastes—such as undigested food, intestinal bacteria, and old cells—and removes them from the body, while the _____________ system filters the blood and collects wastes to remove from the body as urine.
Answer:
Excretory system, and Kidney.
Explanation:
The excretory system helps to regulate the chemical composition of the body fluids by removing metabolic waste such as undigested food, intestinal bacteria, and old cells and helping to retain the proper amount of water, nutrients, and salts in the body.
The main function of the kidney is to filter the blood, kidney help to remove waste from the body as urine, control fluid balance in the body, and keep the right level of electrolytes. Each kidney is bean-shaped in structure and 4-5 inches long in size.
A solution is a mixture containing particles that settles out of the mixture if left undisturbed. True or False
Explanation:
A solution comprises of a homogeneous mixture that means it is composed of one phase (e.g., solid, liquid, gas).Particles do not settle out of in the mixture of a solution and are not visible to our eyes.Components of a solution cannot be separated by using any simple processes like mechanical filtration. Therefore, the given statement is False.0.70 moles of an unknown solid is placed into water to make 150.0 mL of solution. The solution's temperature decreases by 8.4°C. Calculate ∆H for the dissolution of the unknown solid. (The specific heat of the solution is 4.18 J/g･°C and the density of the solution is 1.02 g/mL).
Answer:
[tex]\large \boxed{\text{7.7 kJ}\cdot\text{mol}^{-1} }[/tex]
Explanation:
1. Mass of solution
[tex]\text{Mass of solution} = \text{150 mL} \times \dfrac{\text{1.02 g}}{\text{1 mL}} = \text{153 g}[/tex]
2. Calorimetry
There are two energy flows in this reaction.
q₁ = heat from reaction
q₂ = heat to warm the water
[tex]\begin{array}{ccccl}n\Delta H & + & mC\Delta T &=&0\\\text{0.70 mol}\times \Delta H& + & \text{153 g} \times 4.18 \text{ J}\cdot^{\circ}\text{C}^{-1}\cdot \text{g⁻1} \times (-8.4\, ^{\circ}\text{C}) & = & 0\\0.70\Delta H \text{ mol} & - & \text{5372 J} & = & 0\\& & 0.70\Delta H \text{ mol} & = & \text{5372 J} \\\end{array}[/tex]
[tex]\begin{array}{ccrcl} & & \Delta H & = & \dfrac{\text{ 5372 J}}{\text{0.70 mol}}\\\\ & & & = & \text{7670 J/mol}\\ & & & = & \textbf{7.7 kJ}\cdot\textbf{mol}^{ -\mathbf{-1}} \\\end{array}\\\text{The heat of solution of the compound is $\large \boxed{\textbf{7.7 kJ}\cdot\textbf{mol}^{\mathbf{-1}}}$}[/tex]
The heat of solution is positive, because the water cooled down when the substance dissolved,
To calculate ∆H for the dissolution process, we first calculate the total heat released using the equation q = m × c × ∆T and the provided properties of the solution. We then find ∆H by dividing this total heat by the number of moles of solute, yielding an enthalpy change of -7.57 kJ/mol.
Explanation:The subject of this question relates to chemistry, specifically the concept of enthalpy change (∆H) in the dissolution of a solid in a solution. The first step to calculating ∆H is determining the total heat absorbed or released during the dissolution, which is calculated using the equation q = m × c × ∆T, where m is the mass of the solution, c is the specific heat capacity, and ∆T is the change in temperature.
In this case, we first convert the volume of the solution to mass by using the provided density of the solution (1.02 g/mL). So, the total mass of the solution is 150 mL × 1.02 g/mL = 153.0 g. Next, using the provided temperature and specific heat, we calculate q = (153.0 g) × (4.18 J/g･°C) × (-8.4°C) = -5300.472 J. We use a negative sign because the temperature decreases, meaning the reaction is exothermic and heat is released.
Finally, we calculate ∆H, the enthalpy change per mole of solute, by dividing q by the number of moles of the solute, 0.70 moles. ∆H = -5300.472 J / 0.70 mol = -7572 J/mol, or -7.57 kJ/mol.
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The mass of a gold atom is 3.27 × 10−25 kg . If 3.6 kg of gold is deposited on the negative electrode of an electrolytic cell in a period of 14.88 h , what is the current in the cell in this period? Assume that each gold ion carries one fundamental unit (1.602 × 10−19 C) of positive charge. Answer in units of A.
Answer:
Current is 32.8 A
Explanation:
1 mass of Au atom = 3.27×10⁻²⁵kg
Mass of gold = 3.6 kg
We determine the amount of atoms, in that mass of gold therefore we need a rule of three:
3.27×10⁻²⁵kg is the mass for 1 atom
3.6 kg will be the mass for (3.6 . 1)/3.27×10⁻²⁵ = 1.10×10²⁵ atoms
Now we have to find out the total charge of the 3.6 kg of gold so we make another rule of three:
1 atom of Au has a charge of 1.602 × 10⁻¹⁹ C
1.10×10²⁵ atoms of Au will have a charge of (1.10×10²⁵.1.602 × 10⁻¹⁹) / 1 = 1.76×10⁶ C
Formula for the current is: q = i . t
where q is the C, i the value of current and t, time (s)- We make time conversion from h to s
14.88 h . 3600s / 1h = 53568 s → We replace values:
1.76×10⁶ C = i . 53568s
1.76×10⁶ C / 53568s = i → 32.8 A
An element has two naturally-occurring isotopes. The mass numbers of these isotopes are 123 amu and 125 amu, with natural abundances of 95% and 5%, respectively. Calculate its average atomic mass. Report your answer to 1 decimal place.
Answer:
123.1
Explanation:
The average atomic mass of an element which exhibits isotopy is the average mass of its various isotopes as they occur naturally in any quantity of the element.
Average atomic mass = (95% of 123 amu)+(5% 0f 125 amu)
= (0.95 × 123) + (0.05 × 125)
= 116.85 + 6.25
= 123.1 (to 1 decimal place)
A cylinder with a moveable piston contains 92g of Nitrogen. The external pressure is constant at 1.00 atm. The initial temperature is 200K. When the temperature is decreased by 85 K, by putting it in a lower temperature freezer, the volume will decrease, according to the Ideal Gas Law. Calculate the work for this process. Express your answer in J. The conversion factor between liter atmospheres and joules is 101.3 J
Answer:
Work done in this process = 4053 J
Explanation:
Mass of the gas = 0.092 kg
Pressure is constant = 1 atm = 101325 pa
Initial temperature [tex]T_{1}[/tex] = 200 K
Final temperature [tex]T_{2}[/tex] = 200 - 85 = 115 K
Gas constant for nitrogen = 297 [tex]\frac{J}{kg k}[/tex]
When pressure of a gas is constant, volume of the gas is directly proportional to its temperature.
⇒ V ∝ T
⇒ [tex]\frac{V_{2} }{V_{1} }[/tex] = [tex]\frac{T_{2} }{T_{1} }[/tex] ------------ ( 1 )
From ideal gas equation [tex]P_{1}[/tex] [tex]V_{1}[/tex] = m R [tex]T_{1}[/tex] ------ (2)
⇒ 101325 × [tex]V_{1}[/tex] = 0.092 × 297 × 200
⇒ [tex]V_{1}[/tex] = 0.054 [tex]m^{3}[/tex]
This is the volume at initial condition.
From equation 1
⇒ [tex]\frac{V_{2} }{0.054}[/tex] = [tex]\frac{200}{115}[/tex]
⇒ [tex]V_{2}[/tex] = 0.094 [tex]m^{3}[/tex]
This is the volume at final condition.
Thus the work done is given by W = P [[tex]V_{2}[/tex] - [tex]V_{1}[/tex] ]
⇒ W = 101325 × [ 0.094 - 0.054]
⇒ W = 4053 J
This is the work done in that process.
In a constant‑pressure calorimeter, 70.0 mL of 0.310 M Ba ( OH ) 2 was added to 70.0 mL of 0.620 M HCl . The reaction caused the temperature of the solution to rise from 21.91 ∘ C to 26.13 ∘ C. If the solution has the same density and specific heat as water, what is heat absorbed by the solution?
Explanation:
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How many moles are there in 1.90g of Arsenic? Show work, please.
Answer: 2.53 x 10^-2 moles As ( the answer is in scientific notation )
Classify each of the following possible reactions according to whether a precipitate will form or will not form.
1.) KI+NaCl
2.) Na3PO4+CoCl2
3.) Na2CO3+CuCl2
4.) LiNO3+Na2SO4
5.) CrCl2+Li2CO3
The reactions Na3PO4+CoCl2, Na2CO3+CuCl2 and CrCl2+Li2CO3 produce precipitates.
A precipitate is said to be formed when reaction of two aqueous solutions produces an insoluble product. The insoluble solid product separates from the solution and is called a precipitate.
The full reactions are written below;
KI(aq) + NaCl(aq) ----> KCl(aq) + NaI(aq) 2Na3PO4(aq) + 3CoCl2(aq) ------> Co3(PO4)2(s) + 6NaCl(aq) Na2CO3(aq) + CuCl2(aq) -------> CuCO3(s) + 2NaCl(aq)2LiNO3(aq) + Na2SO4(aq) -------> Li2(SO4)(aq) + 2NaNO3(aq)CrCl2(aq) + Li2CO3(aq) -------> CrCO3(s) + 2LiCl(aq)Hence, the reactions;
2Na3PO4(aq) + 3CoCl2(aq) ------> Co3(PO4)2(s) + 6NaCl(aq) Na2CO3(aq) + CuCl2(aq) -------> CuCO3(s) + 2NaCl(aq)CrCl2(aq) + Li2CO3(aq) -------> CrCO3(s) + 2LiCl(aq)Produce precipitates.
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To determine if a precipitate will form or not, we need to consult solubility rules. By analyzing the compounds in each reaction, we can determine whether they contain soluble or insoluble ions. Based on this analysis, we can classify each reaction as either forming a precipitate or not.
Explanation:In order to determine if a precipitate will form or not, we need to consult solubility rules. According to the solubility rules, compounds containing Li+, Na+, K+, Rb+, Cs+, and NH4+ cations, as well as compounds containing NO3- and C2H3O2- anions, are generally soluble. On the other hand, compounds containing Cl-, Br-, I-, CO32-, and most O2- anions are insoluble, except when paired with the mentioned cations. By applying these rules, we can analyze each reaction:
KI + NaCl: Both KI and NaCl contain soluble ions, so no precipitate will form.Na3PO4 + CoCl2: Since both compounds contain soluble ions, no precipitate will form.Na2CO3 + CuCl2: Na2CO3 contains a soluble ion (Na+), but CuCl2 contains insoluble ions. Thus, a precipitate of CuCO3 will form.LiNO3 + Na2SO4: Both LiNO3 and Na2SO4 contain soluble ions, so no precipitate will form.CrCl2 + Li2CO3: CrCl2 contains soluble ions, but Li2CO3 contains insoluble ions. Therefore, a precipitate of LiCl will form.Learn more about Classifying Reactions here:https://brainly.com/question/21392527
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The carbon cycle is closely linked to which of the following processes?
photosynthesis
precipitation
evaporation
condensation
Answer:
Photosynthesis
Explanation:
As the plants are converting the CO2 into O2... So the photosynthesis reduce the amount of CO2...
Answer:
The answer is photosynthesis
Explanation:
The key processes of the carbon cycle are when the carbon dioxide from the atmosphere is changed into plant material in the biosphere by photosynthesis.
Then organisms in the biosphere obtain energy from respiration and releases carbon dioxide that was orignally changed by photosynthesis.
In a particular experiment, the partial pressures of H 2 and I 2 at equilibrium are 0.710 and 0.888 atm, respectively. The partial pressure of HI is __________ atm.
This is an incomplete question, here is a complete question.
Kp = 0.0198 at 721 K for the reaction:
[tex]2HI(g)\rightleftharpoons H_2(g)+I_2(g)[/tex]
In a particular experiment, the partial pressures of H₂ and I₂ at equilibrium are 0.710 and 0.888 atm, respectively. The partial pressure of HI is __________ atm.
Answer : The partial pressure of HI is, 5.64 atm
Explanation :
For the given chemical reaction:
[tex]2HI(g)\rightleftharpoons H_2(g)+I_2(g)[/tex]
The expression of [tex]K_p[/tex] for above reaction follows:
[tex]K_p=\frac{P_{H_2}\times P_{I_2}}{(P_{HI})^2}[/tex]
We are given:
[tex]P_{H_2}=0.710atm[/tex]
[tex]P_{H_2}=0.888atm[/tex]
[tex]k_p=0.0198[/tex]
Now put all the given values in above equation, we get:
[tex]0.0198=\frac{0.710\times 0.888}{(P_{HI})^2}[/tex]
[tex]P_{HI}=5.64atm[/tex]
Thus, the partial pressure of HI is, 5.64 atm
The correct partial pressure of HI cannot be determined without the accurate initial conditions and changes at equilibrium, since the provided equilibrium partial pressures of H2 and I2 do not match the provided equilibrium constant.
The question states that the partial pressures of H2 and I2 at equilibrium are 0.710 atm and 0.888 atm, respectively, in a reaction H2(g) + I2(g) = 2 HI(g). Given the partial pressure at the start for HI was 1 atm and we are looking to find the equilibrium partial pressure of HI, we can apply the equilibrium constant Kp. However, the values given are part of a typo or irrelevant to the scenario as they do not match with the equilibrium constant Kp provided (1.82 imes 10-2 at 698K), and since such calculations require an accurate accounting of initial conditions and changes at equilibrium, providing an exact value for the partial pressure of HI would be speculative.
a solution of hydrochloric acid of unknown concentration was titrated with .21 M NaOH. if a 75 ml sample of the HCl solution required exactly 13ml of the NaOH solution to reach the equivalence point, what was the ph of the HCl solution
Answer:
pH of HCl solution is 1.44
Explanation:
NaOH is a monoprotic base and HCl is a monobasic acid.
Neutralization reaction: [tex]NaOH+HCl\rightarrow NaCl+H_{2}O[/tex]
According to balanced reaction, 1 mol of NaOH neutralizes 1 mol of HCl.
Number of moles of NaOH in 13 mL of 0.21 M NaOH
= [tex]\frac{0.21}{1000}\times 13mol=0.00273mol[/tex]
let's assume concentration of HCl is C (M)
Then, number of moles of HCl in 75 mL of C (M) HCl solution
= [tex]\frac{75}{1000}\times Cmol=\frac{75C}{1000}mol[/tex]
So, we can write, [tex]\frac{75C}{1000}=0.00273[/tex]
or, [tex]C=0.0364[/tex]
1 mol of HCl contains 1 mol of [tex]H^{+}[/tex]
So, concentration of [tex]H^{+}[/tex] in 0.0364 M HCl, [tex][H^{+}]=0.0364M[/tex]
Hence, [tex]pH=-log[H^{+}]=-log(0.0364)=1.44[/tex]
Consider the following reaction: 2 H2(g) + 2 NO(g) → 2 H2O(g) + N2(g) If the concentration of NO changed from 0.100 M to 0.025 M in the first 15 minutes of the reaction, what is the average rate of the reaction during this time interval?
Final answer:
The average rate of the reaction is -0.005 M/min.
Explanation:
The average rate of a reaction can be calculated by using the change in concentration of a reactant or product divided by the time interval. In this case, the concentration of NO changed from 0.100 M to 0.025 M in 15 minutes. You can calculate the average rate of the reaction by dividing the change in concentration by the time interval:
Average rate = (Final concentration - Initial concentration) / Time
Average rate = (0.025 M - 0.100 M) / 15 minutes
Average rate = -0.075 M / 15 minutes = -0.005 M/min
How many moles of HNO3 are present if 4.90×10−2 mol of Ba(OH)2 was needed to neutralize the acid solution?
Answer:
0.098 moles of HNO₃ are present if 4.90×[tex]10^{-2}[/tex] mol of Ba(OH)₂ was needed to neutralize the acid solution
Explanation:
1 mole of Ba(OH)₂ contains 2 moles of OH- ions.
Hence, 0.049 moles of Ba(OH)2 contains x moles of OH- ions.
cross multiplying, we have
1 mole * x mole = 2 moles * 0.049 mole
x mole = 2 * 0.049 / 1
x mole = 0.098 moles of OH- ions.
1 mole of OH- can neutralize 1 mole of H+
Therefore, 0.098 moles of HNO₃ are present if 0.049 moles of Ba(OH)₂ was needed to neutralize the acid solution.
Fatty acids may differ from one another in: a. chain length and degree of saturation b. the number of calories and in whether they contain carbon atoms c. degree of saturation and in the number of sulfur atoms d. chain length and in the number of nitrogen atoms e.
Answer:
a. chain length and degree of saturation.
Explanation:
Fatty acids can be classified according to the length of their chain, for example, in short (if it has less than 8 carbons), medium (between 8-12 carbons), long (between 12-18 carbons) and very long (if it has less than 18 carbons); they are also classified according to their degree of unsaturation, in saturated, monounsaturated and polyunsaturated; and according to the isomerism in cis and trans fatty acids.
Fatty acids may differ from one another in chain length and degree of saturation. Therefore, the correct option is option A.
Fatty acid is a crucial part of lipids, which are the parts of living things including plants, animals, and microbes that may be dissolved in fat. A fatty acid normally consists of a chain that is straight with a even amount of carbon atoms, hydrogen atoms running along the entire length of the chain, a carboxyl group (COOH) at one end, and hydrogen atoms running the duration of the chain. It forms an acid (carboxylic acidic solution) because of the carboxyl group. The acid is saturated if there are only single carbon-to-carbon bonds. Fatty acids may differ from one another in chain length and degree of saturation.
Therefore, the correct option is option A.
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In the first step of hydroboration mechanism, why is an arrow drawn from the pi bond of the alkene to the B atom of the borane reagent signifying the pi electrons are used to make a new C-B bond?
Answer:
To fulfill octet of B atom in borane, nucleophilic attack by pi electrons of alkene takes place with electrophilic B center in borane.
Explanation:
In Borane ([tex]BH_{3}[/tex]), B atom has energetically vacant 2p orbital and thereby octet is incomplete.Therefore B center in borane act as an electrophilic center.
In alkene, pi bonding electrons are loosely bound together due to side on overlap of two constituent p-orbitals. Hence this pi bond can be easily broken. Alternatively, we can say that pi bond in alkene act as a potential nucleophile.
The first step of hydroboration occurs in a concerted manner where pi electrons of alkene first attack vacant 2p orbital of B in borane to fulfill it's octet (represented by an arrow drawn from alkene to B atom) and forms a 4 memebered cyclic intermediate. Simulaneously, a B-H bond in borane is donated to alkene through 3c-2e bond (3 center-2 electron bond).
Full mechanism has been shown below.
One significant difference between gases and liquids is that ________. a gas is made up of molecules a gas expands to fill its container a gas may consist of both elements and compounds gases are always mixtures All of the above answers are correct
Answer:
One significant difference between gases and liquids is that a gas expands to fill its container.
Explanation:
One of the biggest differences between liquids and gases is that liquids have a defined volume and gases do not. A gas has no defined shape or volume, it acquires the shape and volume of the container in which it is located. It is the tendency of gases to increase in volume due to the force of repulsion that works between their molecules.
One significant difference between gases and liquids should be that a gas expands to fill its container.
Difference between the gases and liquids:It is the biggest difference that lies between the liquids and gases is that the liquid should contain the volume while the gas does not. Also, the gas does not have a defined shape or volume.
It purchased the shape and the container volume where it should be located.
Also, there is the gas tendency for increasing the volume because of the repulsion of the force that should be worked between the molecules.
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Part 1: Ionic Bonding 1. Choose Sodium (Na). a. What type of element is it? b. How many valence electrons does it have? 2. Choose Fluorine (F). a. What type of element is it? b. How many valence electrons does it have? 3. Answer the question on the screen, "What type of bond is this combination likely to form?" a. Circle: Ionic or Covalent? b. Choose the appropriate number of atoms to make the bond. Record the number of each atom below: 4. Watch the final animation closely (it will play continuously). a. Describe the change in the number of valence electrons in the atoms as the bond is successfully formed: b. What does the positive (+) charge indicate (mention specific subatomic particles in your answer)? c. What does the negative (-) charge indicate (mention specific subatomic particles in your answer)? d. Record the name and molecular formula for the compound below:
Answer:
Explanation:
Sodium is a group 1 element with atomic number 1. It has 11 electrons. It is soft reactive metal. It has 1 valence electron.
Fluorine is a group 7 element, a hologen with 7 valence electron. It is a most reactive non metal.
When sodium react with fluorine, ionic bond is formed in the resulting compound sodium fluoride.
One sodium and fluorine each totaling 2 atoms are enough to make the bond.
As the bond is formed, both atoms have octet structure. That is they each have 8 electrons on their outermost shells.
The positive charge on sodium indicates that sodium had lost 1 electron to fluorine atom.
The negative charge on fluorine ion indicates that fluorine atom had gained 1 electron from sodium atom to form negative ion.
The name of the compound is sodium fluoride with formula NaF.
Answer:
The reaction of 1st group element Na and 7th group element F, results in formation of Sodium fluoride (NaF).
Explanation:
1. (a) Sodium (Na) is element belonging to the first group of the periodic table.
(b) The atomic number of Na is 11 and after distribution it has 1 valence electron.
2. (a) Fluorine (F) is the halogen element and belongs to group 7 of the periodic table.
(b) The atomic number of F is 19 and it has 7 valence electrons.
3. The reaction of Na with F results in an ionic interaction with the formation of NaF (Sodium fluoride).
(a) The reaction and combination of Na and F is likely to be ionic in nature.
(b) The one valence electron of Na and F are involved in formation of bond. Total 2 electrons are involved.
4. (a) The successful formation of bond result in octet completion of NaF by sharing of electrons. Both the elements share 8 electrons, i.e. 7 electrons of F and 1 electron of Na.
(b) The +ve charge is imparted for the loss of electron . Na lost its 1 valence electron to F for bond formation and thus imparts the +ve charge.
(c) The -ve charge is imparted with the gain of electron. In reaction of Na with F, fluorine being more electronegative gains its electrons from Na and imparts a -ve charge.
(d) The reaction of Na with F results in the formation of compound known as sodium fluoride with the molecular formula NaF.
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Briefly explain the observed effect of the acetylcholine concentration on the rate of the enzyme-catalyzed reaction
Explanation:
It is observed that when the concentration of acetylcholine remains constant in the reaction of an aqueous solution, the speed of the enzyme-catalyzed reaction or the formation of the product increases with increasing concentrations of substrate. The reaction rate is directly proportional to the concentration of acetylcholine. At very low concentrations of acetylcholine, there is a small increase in the concentration of the substrate which results in a large increase of the rate in reaction.In CF4 and NF3, the ___electron groups on the central C and N atoms have a ___ arrangement. The shapes of the molecules are determined by the number of ___ of electrons: since CF4 has ___ bonded atom(s) and ___ lone pair(s) of electrons, the shape is ___. Since NF3 has ___ bonded atom(s) and ___ lone pair(s) of electrons, the shape is ___.
The molecules CF4 and NF3 have five electron groups arranged in a trigonal bipyramidal fashion. CF4, with four bonded atoms and zero lone pairs, is tetrahedral. NF3, with three bonded atoms and one lone pair, is trigonal pyramidal.
Explanation:In CF4 and NF3, the five electron groups on the central C and N atoms have a trigonal bipyramidal arrangement. The shapes of the molecules are determined by the number of pairs of electrons: since CF4 has four bonded atoms and zero lone pairs of electrons, the shape is tetrahedral. Since NF3 has three bonded atoms and one lone pair of electrons, the shape is trigonal pyramidal.
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CF4 and NF3 have a tetrahedral electron-pair geometry due to four electron groups on the central atoms. CF4 has a tetrahedral shape due to four bonded atoms and no lone pairs, while NF3 has a trigonal pyramidal shape due to three bonded atoms and one lone pair.
Explanation:In CF4 and NF3, the four electron groups on the central C and N atoms have a tetrahedral arrangement. The shapes of the molecules are determined by the number of bonded atoms and lone pairs of electrons:
In CF4, there are four bonded atoms and no lone pairs of electrons, resulting in a tetrahedral shape.In NF3, there are three bonded atoms and one lone pair of electrons, resulting in a trigonal pyramidal shape.This distinction occurs because although both molecules have a tetrahedral electron-pair geometry, the presence of a lone pair of electrons on nitrogen in NF3 distorts the geometry to be trigonal pyramidal at the molecular level.
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A decrease of one unit in the pH scale above represents a tenfold increase in the hydrogen ion concentration of a solution. For example, a solution having a pH of 4 is 10 times more acidic than a solution with a pH of 5. If acid precipitation rain changes the pH of a pond from 7.5 to 6.5, the level of hydrogen ion has changed by a factor of ________
A) 2.0
B) 10
C) 13.0
D) 100
E) 0.01
Answer:
The level of hydrogen ion has increased by a factor of 10.
Explanation:
We know, [tex]pH=-log[H^{+}][/tex]
where [tex][H^{+}][/tex] represents concentration of [tex]H^{+}[/tex] in molarity
Here [tex](pH)_{final}=6.5[/tex]
So, [tex][H^{+}]_{final}=10^{-6.5}M[/tex]
Here [tex](pH)_{initial}=7.5[/tex]
So, [tex][H^{+}]_{initial}=10^{-7.5}M[/tex]
Hence, change in pH = [tex]\frac{[H^{+}]_{final}}{[H^{+}]_{initial}}[/tex] = [tex]\frac{10^{-6.5}M}{10^{-7.5}M}=10[/tex]
So, the level of hydrogen ion has increased by a factor of 10.
Option (B) is correct
A sample of 8.4 grams of NaOH is dissolved into 620 mL of aqueous 0.250 M NaOH (assume no volume change). This solution is then poured into 1.65 gallons of water. (You may assume that the two volumes can be added.) What is the concentration of NaOH in the final solution
Answer:
The concentration of NaOH in the final solution 0.0584 mole/lit
Explanation:
[tex]moles of NaOH =[/tex] [tex]\frac{Weight}{Molecular weight}[/tex] [tex]=\frac{8.4}{40}=0.21 mole[/tex]620 ml of aqueous 0.25 M NaOH [tex]=0.25X 620 = 0.155mole[/tex]Total moles = 0.21 + 0.155 = 0.365 moles1.65 gallons = 3.785 lit x 1.65 = 6.245929 lit (∵ 1 gallon = 3.785 lit)[tex]Molarity =\frac{No. of moles}{Volume(lit)}[/tex]So Molarity of the solution after mixing [tex]=\frac{0.365}{6.245929} = 0.0584 (M)[/tex]
∴ The concentration of NaOH in the final solution 0.0584 mole/lit
The concentration of NaOH in the final solution is thus 0.0531 M.
To determine the concentration of NaOH in the final solution after 8.4 grams of NaOH are dissolved into 620 mL of 0.250 M NaOH solution, which is then mixed into 1.65 gallons of water, follow these steps:
First, calculate the moles of NaOH initially dissolved. Knowing NaOH has a molar mass of 40.0 g/mol, 8.4 g of NaOH translates to 0.21 moles of NaOH.
Add the moles from the initial 620 mL of 0.250 M solution. That will be 0.250 moles/L * 0.62 L = 0.155 moles.
Combine the moles from both sources for a total of 0.365 moles of NaOH.
Convert 1.65 gallons of water to liters (1 gallon = 3.78541 L), making 1.65 gallons equal to 6.245 liters. Adding this to the initial 0.62 L yields a total final volume of 6.865 liters.
Finally, calculate the final concentration by dividing the total moles of NaOH by the final volume of solution in liters to find the molarity of the final solution.
The concentration of NaOH in the final solution is thus 0.0531 M.
A solution of methanol and water has a mole fraction of water of 0.312 and a total vapor pressure of 211 torr at 39.9 ∘C. The vapor pressures of pure methan ol and pure water at this temperature are 256 torr and 55.3 torr, respectively. ls the solution ideal? If not, what can you say about the relative strengths of the solute-solvent interactions compared to the solute-solute and solvent-solvent interactions?
Answer:
Weaker
Explanation:
The strategy here is to use Raoult´s law to calculate the theoretical vapor pressure for the concentrations given and compare it with the experimental value of 211 torr.
Raoult´s law tell us that for a binary solution
P total = partial pressure A + partial pressure B = Xa PºA + Xb PºB
where Xa and Xb are the mol fractions, and PºA and PºB are the vapor pressures of pure A and pure B, respectively
For the solution in question we have
Ptotal = 0.312 x 55.3 torr + ( 1- 0.312 ) x 256 torr ( XA + XB = 1 )
Ptotal = 193 torr
Since experimentally, the total vapor pressure is 211 and our theoretical value is smaller ( 193 torr ), we can conclude the interactions solute-solvent are weaker compared to the solute-solute and solvent-solvent interactions.
Using Raoult's law, we can conclude that if the actual total vapor pressure of the solution does not match the calculated value, the solution is not ideal. Deviations from the ideal behavior indicate that the solute-solvent interactions differ in strength from solute-solute and solvent-solvent interactions.
To determine if the solution is ideal and to discuss the strengths of solute-solvent interactions compared to solute-solute and solvent-solvent interactions, we can use Raoult's law. Raoult's law states that the partial vapor pressure of each component in an ideal solution is equal to the product of the mole fraction of the component in the liquid phase and the vapor pressure of the pure component.
The expected total vapor pressure for an ideal solution can be calculated by summing the partial pressures of each component. For methanol (CH3OH), with a mole fraction of 1 - 0.312 = 0.688 and a vapor pressure of 256 torr, the expected partial pressure is partial pressure of methanol = 0.688 × 256 torr. For water (H2O), with a mole fraction of 0.312 and a vapor pressure of 55.3 torr, the expected partial pressure is partial pressure of water = 0.312 × 55.3 torr. By adding these two values together, we would get the expected total vapor pressure of an ideal solution.
If the calculated total vapor pressure using Raoult's law does not match the actual total vapor pressure of 211 torr, the solution is not ideal. In that case, the deviation indicates that the solute-solvent interactions differ in strength from the solute-solute and solvent-solvent interactions. If the actual vapor pressure is lower than expected, the solute-solvent interactions are stronger, suggesting a negative deviation. Conversely, a higher actual vapor pressure indicates weaker solute-solvent interactions relative to pure components, leading to a positive deviation.