The expression that describes the heat evolved in a chemical reaction when carried out at constant pressure is ΔH = ΔE - w. Here, ΔH represents the enthalpy change, ΔE represents the internal energy change (also symbolized as ΔU), and w represents the work done.
Enthalpy is the sum of the internal energy of a system and the product of its pressure and volume. At constant pressure, the change in enthalpy is equal to the heat evolved or absorbed in the reaction. This is because any work done during the reaction is accounted for in the change in volume term of enthalpy, and at constant pressure, this term is constant. Therefore, the heat evolved or absorbed in the reaction is solely responsible for the change in enthalpy.
When a chemical reaction is carried out at constant pressure, the heat evolved in the reaction can be described using the symbol q, which represents heat. This is because, at constant pressure, the change in internal energy (symbolized by ΔE or ΔU) is equal to the heat absorbed or released in the reaction (represented by q) minus any work done (represented by w). Therefore, to explain the heat evolved in a chemical reaction at constant pressure, we would use the symbol q.
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The central atom of a molecule that exceeds the octet rule must come from period ______ or below.
The central atom of a molecule that exceeds the octet rule must come from period 3 or below.
This is because elements in these periods have empty d-orbitals available for hybridization, which allows them to form more than four covalent bonds and exceed the octet rule.
Examples of such elements include sulfur (S), phosphorus (P), and chlorine (Cl). Elements in higher periods, such as xenon (Xe) and radon (Rn), can also exceed the octet rule but are relatively rare in organic chemistry.
It is important to note that not all atoms follow the octet rule, and some can have fewer than eight electrons in their valence shell due to their unique electronic configurations.
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Gas in a balloon occupies 2. 5 L at 300 K. At what temperature will the balloon expand to 7. 5 L?
Gas in a balloon occupies 2. 5 L at 300 K. The temperature will the balloon expand to 7. 5 L is 900 K.
The Charles law states that the volume of the ideal gas is directly proportional to absolute temperature at the constant pressure.
V ∝ T
The Charles’ Law is expressed as :
V₁ / T₁ = V₂ / T₂
Where,
The volume , V₁ = 2.5 L
The temperature, T₁ = 300 K
The volume, V₂ = 7.5 L
The temperature, T₂ = ?
T₂ = V₂ T₁ / V₁
T₂ = ( 7.5 × 300 ) / 2.5
T₂ = 900 K
The temperature that will the balloon expand to the 7. 5 L is 900 K.
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Write the following chemical reactions and balance:
Potassium reacts with sodium oxide to produce potassium oxide and sodium
The chemical reaction between potassium and sodium oxide results in the formation of potassium oxide and sodium. The balanced equation for this reaction is:
2K + Na₂O -> K₂O + 2Na
This reaction is an example of a displacement reaction, where a more reactive element (potassium) displaces a less reactive element (sodium) from its compound (sodium oxide). The displacement occurs because potassium has a greater tendency to lose electrons and form cations compared to sodium.
Potassium oxide is an important chemical compound with many industrial applications, including in the production of glass, ceramics, and fertilizers. It is also used as a drying agent and catalyst in organic reactions.
Sodium, on the other hand, is a highly reactive metal that is commonly found in compounds such as sodium chloride (table salt) and sodium hydroxide (lye). It is an essential element for many biological processes, including nerve and muscle function.
Overall, this chemical reaction between potassium and sodium oxide is important because it highlights the reactivity of these elements and the formation of useful compounds such as potassium oxide. It also emphasizes the importance of balancing chemical equations to ensure that the reactants and products are in the correct proportions.
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Three inert gases X,E and Z are pumped into an evacuated 5. 00l rigid container until the total pressure is 3. 00 atm. Determine the partial pressure of gas X if 0. 500 moles of each is used
The partial pressure of gas X if 0. 500 moles of each is used is 1 atm.
In a gas mixture, the pressure exerted by individual gases on the walls of the container is known as partial pressure of the gas. The sum of the partial pressures of all the gas molecules fives the total pressure of the gas.
Partial pressure = number of moles/ total moles × total pressure
since, 0.5 moles of each gas is used,
partial pressure of X is
= moles of X /total moles of X,E,Z × total pressure
= 0.5 moles × 3 atm/ 1.5 moles
= 1 atm
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A sample of 0. 0400 mol potassium hydroxide, KOH was dissolved in water to yield 20. 0 mL of solution. What is the molarity of the solution?
0. 4M
250M
2. 0M
2. 00x 10-3M
The molarity of the solution is 2.0 M, option C is correct.
The molarity of a solution is defined as the number of moles of solute per liter of solution. In this problem, we are given the amount of solute, which is 0.0400 mol of potassium hydroxide, KOH, and the volume of the solution, which is 20.0 mL.
To find the molarity, we need to convert the volume to liters by dividing by 1000:
20.0 mL ÷ 1000 = 0.0200 L
Now we can use the formula for molarity:
Molarity = moles of solute ÷ liters of solution
Molarity = 0.0400 mol ÷ 0.0200 L = 2.00 M
Hence, option C is correct.
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The complete question is:
A sample of 0. 0400 mol potassium hydroxide, KOH was dissolved in water to yield 20. 0 mL of solution. What is the molarity of the solution?
A) 0.4M
B) 250M
C) 2.0M
D) 2.00x 10⁻³M
a generic salt, ab3, has a molar mass of 305 g/mol and a solubility of 4.30 g/l at 25 °c. ab3(s)↽−−⇀a3 (aq) 3b−(aq) what is the ksp of this salt at 25 °c?
The dissociation reaction for the salt AB3 is:
AB3(s) ↔ A3+(aq) + 3B-(aq)
Let's assume the solubility of AB3 in water at 25 °C is x mol/L. Then, the equilibrium concentrations of A3+ and B- can be expressed as x and 3x, respectively.
The Ksp expression for AB3 is:
Ksp = [A3+][B-]^3 = x(3x)^3 = 27x^4
The molar mass of AB3 is 305 g/mol, so the number of moles in 4.30 g (the solubility) is:
n = 4.30 g / 305 g/mol = 0.0141 mol/L
Therefore, the solubility of AB3 at 25 °C is:
x = 0.0141 mol/L
Substituting this into the Ksp expression:
Ksp = 27x^4 = 27(0.0141)^4 = 5.6 x 10^-9
Therefore, the Ksp of AB3 at 25 °C is 5.6 x 10^-9.
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For each phase change, determine the sign of Δ
H and Δ
S. Place the appropriate items to their respective bins.
a. Sublimation
b. Freezing
c. Boiling
d. Deposition
e. Melting
f. Condensation
The sign of ΔH and ΔS can be determined by looking at the direction of the phase change and the molecular behavior of the substance.
a. Sublimation:
ΔH: Positive (endothermic process, energy is absorbed)
ΔS: Positive (increase in entropy, as a solid transitions to a gas)
b. Freezing:
ΔH: Negative (exothermic process, energy is released)
ΔS: Negative (decrease in entropy, as a liquid becomes a solid)
c. Boiling:
ΔH: Positive (endothermic process, energy is absorbed)
ΔS: Positive (increase in entropy, as a liquid transitions to a gas)
d. Deposition:
ΔH: Negative (exothermic process, energy is released)
ΔS: Negative (decrease in entropy, as a gas becomes a solid)
e. Melting:
ΔH: Positive (endothermic process, energy is absorbed)
ΔS: Positive (increase in entropy, as a solid transitions to a liquid)
f. Condensation:
ΔH: Negative (exothermic process, energy is released)
ΔS: Negative (decrease in entropy, as a gas becomes a liquid)
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What are two types of matter that are considered pure?.
Answer: Elements and compounds are both examples of pure substances.
Explanation:
write balanced equations for each of the processes described below. (use the lowest possible coefficients. omit states-of-matter.)
1. Balanced equation for the combustion of propane: [tex]C_3H_8 + 5O_2\ - > 3CO_2 + 4H_2O.[/tex]
2. Balanced equation for the reaction between hydrochloric acid and sodium hydroxide:[tex]HCl + NaOH\ - > NaCl + H_2O.[/tex]
3. 3. Balanced equation for the decomposition of calcium carbonate upon heating: [tex]CaCO_3\ - > CaO + CO_2.[/tex]
1. [tex]C_3H_8 + 5O_2\ - > 3CO_2 + 4H_2O.[/tex]
This reaction shows that propane[tex](C_3H_8)[/tex] reacts with oxygen[tex](O_2)[/tex] from the air to produce carbon dioxide[tex](CO_2)[/tex] and water[tex](H_2O)[/tex] in a balanced chemical equation.
2. [tex]HCl + NaOH\ - > NaCl + H_2O.[/tex]
This reaction demonstrates that hydrochloric acid (HCl) reacts with sodium hydroxide (NaOH) to produce sodium chloride (NaCl) and water [tex](H_2O)[/tex] in a balanced chemical equation.
3. [tex]CaCO_3\ - > CaO + CO_2[/tex].
This reaction illustrates that when calcium carbonate[tex](CaCO_3)[/tex] is heated, it decomposes to produce calcium oxide (CaO) and carbon dioxide [tex](CO_2)[/tex] in a balanced chemical equation.
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--The complete Question is, Write balanced equations for each of the processes described below:
1. Combustion of propane (C3H8) in air to produce carbon dioxide and water.
2. Reaction between hydrochloric acid (HCl) and sodium hydroxide (NaOH) to produce sodium chloride (NaCl) and water (H2O).
3. Decomposition of calcium carbonate (CaCO3) upon heating to produce calcium oxide (CaO) and carbon dioxide (CO2). --
If your end product is 200. 0 g KMnO4 how much KOH did you start with?
Both Scientist A and Scientist B achieved same yield of KMnO₄, indicating they obtained the maximum possible amount based on the starting materials and reaction conditions. The percent yield for Scientist A is approximately 100% and for Scientist B, it is also approximately 100%
To solve these problems, let's go step by step:
1. If the end product is 1.5 moles of KMnO₄, according to the balanced chemical equation:
2 MnO₂ + 4 KOH + O₂ -> 2 KMnO₄ + 2 KOH + H₂
We can see that the stoichiometric ratio between KMnO₄ and MnO₂ is 2:2. Therefore, the number of moles of MnO₂ used in the reaction would be 1.5 moles.
2. To determine how much KOH was used when the end product is 200.0 g of KMnO₄:
Again, using the balanced chemical equation, we can see that the stoichiometric ratio between KMnO₄ and KOH is 2:4. Therefore, the number of moles of KOH used would be twice the number of moles of KMnO₄.
Given that the molar mass of KMnO₄ is approximately 158.034 g/mol, we can calculate the number of moles of KMnO₄:
moles of KMnO₄ = mass of KMnO₄ / molar mass of KMnO₄
moles of KMnO₄ = 200.0 g / 158.034 g/mol
moles of KMnO₄ ≈ 1.265 mol
Since the stoichiometric ratio is 2:4, the number of moles of KOH would be twice that:
moles of KOH = 2 * moles of KMnO₄
moles of KOH = 2 * 1.265 mol
moles of KOH ≈ 2.53 mol
3. To determine the theoretical yield of potassium permanganate when starting with 500 g of MnO₂:
Again, using the balanced chemical equation, we can see that the stoichiometric ratio between MnO₂ and KMnO₄ is 2:2. Therefore, the molar ratio is 1:1.
Given that the molar mass of MnO₂ is approximately 86.9375 g/mol, we can calculate the number of moles of MnO₂:
moles of MnO₂ = mass of MnO₂ / molar mass of MnO₂
moles of MnO₂ = 500 g / 86.9375 g/mol
moles of MnO₂ ≈ 5.75 mol
Since the stoichiometric ratio is 1:1, the theoretical yield of KMnO₄ would be equal to the number of moles of MnO₂:
Theoretical yield of KMnO₄ = moles of MnO₂
Theoretical yield of KMnO₄ ≈ 5.75 mol
4. To calculate the percent yield for Scientist A and Scientist B, we need the actual yields of KMnO₄ produced by each scientist. Let's assume Scientist A produces 83.67 g of KMnO₄ and Scientist B produces 81.35 g of KMnO₄.
Percent yield = (actual yield / theoretical yield) * 100
Percent yield for Scientist A = (83.67 g / (2 * 83.67 g)) * 100 ≈ 100%
Percent yield for Scientist B = (81.35 g / (2 * 81.35 g)) * 100 ≈ 100%
5. Both Scientist A and Scientist B achieved 100% yield, indicating that they obtained the maximum possible amount of KMnO₄ based on the starting amount
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Complete question :
If your end product is 1.5 moles of KMnO4. how many moles of manganese oxide were used in the reaction? The equation for the production of potassium permanganate is as follows: 2 MnO2+ 4 KOH + O2- 2 KMnO4 + 2 KOH + H2 You must show all work to receive full credit If your end product is 200.0 g KMnO4 how much KOH did you start with? The equation for the production of potassium permanganate is as follows: 2 MnO2+ 4 KOH + O2+ 2 KMnO4 + 2 KOH + H2 You must show all work to receive full credit. A company manufacturing KMnO, wants to obtain the highest yield possible Two of their research scientists are working on a technique to increase the yield Both scientists started with 500 g of manganese oxide What is the theoretical yield of potassium permanganate when starting with 500 g MnO2? The equation for the production of potassium permanganate is as follows 2 MnO2+ 4 KOH + 02 - 2 KMnO, +2 KOH + H2 You must show all work to receive tul credit Scientist A produces 83.67 g KMnO4 while Scientist B produces 81.35 g KMnO4 What is the percent yield for Scientist A? What is the percent yield for Scientist B? You must show all work to receive full credit. The equation for the production of potassium permanganate is as follows: 2 MnO2+ 4 KOH + O2-2 KMnO4+2 KOH + H2 of the two scientists' results, whose would you present to the boss as an example of the product your company manufacturers? Justify your answer with evidence and scientific reasoning BIETE
C (g) + e (g) <-- --> 2 w (g)
initially, there are 3.5 moles of w placed in a 2.5 l evacuated container. equilibrium is allowed to establish and the value of k = 2.34 e-5 for the reaction under current conditions. determine the concentration of e at equilibrium.
a. [e] = 8.352 e -6
b. [e] = 0.00578
c. [e] = 0.00289
d. cannot solve using 5% approximation rule
The answer is (d) cannot solve using 5% approximation rule.
The balanced equation for the reaction is:
C(g) + e(g) ⇌ 2W(g)
The equilibrium constant expression is given by:
Kc = [W]^2 / [C][e]
At equilibrium, let's assume that x moles of C react with x moles of e to produce 2x moles of W. Therefore, the equilibrium concentrations are:
[C] = (3.5 - x) mol/L
[e] = (x) mol/L
[W] = (2x) mol/L
Substituting these values :
Kc = [(2x)^2] / [(3.5 - x)(x)]
Simplifying this expression:
4x^2 + 2.34x - 8.19 = 0
Solving this quadratic equation :
x = (-2.34 ± sqrt(2.34^2 - 4(4)(-8.19))) / (2(4))
x = (-2.34 ± 3.64) / 8
We can ignore the negative root as it does not make physical sense. Therefore:
x = 0.4575 mol/L
Thus, the concentration of e at equilibrium is:
[e] = 0.4575 mol/L
Therefore, the answer is (d) cannot solve using 5% approximation rule.
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How many kJ of heat would be released when 250g of water freezes?
A. 565 kJ
B. -83.5 kJ
C. 83.5 kJ
D. -565 kJ
The total KJ of heat that would be released is B. -83.5 kJ
How do we solve for the KJ of heat that would be released?When a something in a liquid or semi-liquid freezes, it undergoes a phase change to a solid state, and this process involves a release of heat.
For example, when water freezes, it releases 333.5 kJ of heat per kg of water that freezes
To be able to calculate the heat released, we need to use the formula:
q = m x Lf
But first, we must convert grams to kg
m = 250 g x (1 kg / 1000 g) = 0.25 kg
q = 0.25 kg x 333.5 kJ/kg
q = 83.375 kJ
The answer is turned to the negative since heat is released.
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How many grams of oxygen would be needed to completely react with 254 g of tristearin, C57H110O6, by the following reaction:
2C57H110O6 + 163O2 114CO2 + 110H2O
You would need 740.1 grams of oxygen to completely react with 254 grams of tristearin, C₅₇H₁₁₀O₆, in the given reaction.
To find out how many grams of oxygen are needed to completely react with 254 g of tristearin, C₅₇H₁₁₀O₆, in the given reaction, follow these steps:
1. Calculate the molar mass of tristearin (C₅₇H₁₁₀O₆) and oxygen (O₂).
2. Convert grams of tristearin to moles using its molar mass.
3. Use stoichiometry to find the moles of oxygen needed.
4. Convert moles of oxygen to grams using its molar mass.
Molar mass of tristearin: (57 * 12.01) + (110 * 1.01) + (6 * 16.00) = 891.62 g/mol
Moles of tristearin: 254 g / 891.62 g/mol = 0.285 moles
Moles of oxygen needed: 0.285 moles * (163 O₂ / 2 C₅₇H₁₁₀O₆) = 23.16 moles
Molar mass of O₂: 2 * 16.00 = 32.00 g/mol
Grams of oxygen needed: 23.16 moles * 32.00 g/mol = 740.1 g
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14. Lab Analysis: You forgot to label your chemicals and do not know whether your unknown solution is strontium nitrate or magnesium nitrate. You use the solutions potassium carbonate and potassium sulfate in order to determine your mistake. unknown + potassium carbonate & unknown + potassium sulfate . Write the complete balanced molecular equation(s) below of the reaction(s) that occurred, including the states of matter. HINT: Try writing ALL possible reactions that could have been created, and then decide which reactions actually occurred.
Unknown + Potassium Carbonate → Potassium Nitrate + Unknown Carbonate
[tex]Sr(NO_3)_2[/tex] + [tex]K_2CO_3[/tex] → [tex]2KNO_3[/tex] + [tex]SrCO_3[/tex] (if the unknown is strontium nitrate)
[tex]Mg(NO_3)_2[/tex]+ [tex]K_2CO_3[/tex] → [tex]2KNO_3[/tex] + [tex]MgCO_3[/tex] (if the unknown is magnesium nitrate)
Here are the balanced molecular equations for the reactions that could have occurred between the unknown solution (either strontium nitrate or magnesium nitrate) and potassium carbonate and potassium sulfate: Unknown + potassium carbonate → potassium nitrate + magnesium or strontium carbonate (depending on the unknown)
Unknown + potassium sulfate → potassium nitrate + magnesium or strontium sulfate (depending on the unknown)
Unknown + Potassium Sulfate → Potassium Nitrate + Unknown Sulfate
[tex]Sr(NO_3)_2[/tex] + [tex]K_2SO_4[/tex] → [tex]2KNO_3[/tex] + [tex]SrSO_4[/tex] (if the unknown is strontium nitrate)
[tex]Mg(NO_3)_2[/tex] + [tex]K_2SO_4[/tex] → [tex]2KNO_3[/tex] + [tex]MgSO_4[/tex] (if the unknown is magnesium nitrate)
To determine which reaction occurred, you would need to observe which products were formed. If [tex]SrCO_3[/tex] or [tex]SrSO_4[/tex] were formed, then the unknown was strontium nitrate.
If [tex]MgCO_3[/tex] or [tex]MgSO_4[/tex] were formed, then the unknown was magnesium nitrate.
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Find the mass of a sample of water if its temperature dropped 24. 8°C
when it lost 870 J of heat. Hint. Which formula are you going to use? See
interactive PPT. Don't forget the unit. Show your work.
How much heat is required to warm a 135g cup of water from 15 °C to
35°C? Hint: the water is in a cup so what state of matter and specific heat?
Show your work.
1. The mass of the water sample is approximately 8.77 grams.
2. Approximately 11,322 Joules of heat are required to warm a 135g cup of water from 15°C to 35°C.
We're given the values:
Q = -870 J (lost heat, so negative value)
ΔT = -24.8°C (temperature dropped)
c = 4.18 J/(g°C) (specific heat capacity of water)
Rearrange the formula to solve for mass:
m = Q / (cΔT)
Plug in the values:
m = -870 / (4.18 × -24.8)
m ≈ 8.77 g
The mass of the water sample is 8.77 grams.
We're given the values:
m = 135 g
ΔT = 35°C - 15°C = 20°C
c = 4.18 J/(g°C) (specific heat capacity of water)
Now, use the formula Q = mcΔT to find the heat required:
Q = 135 × 4.18 × 20
Q ≈ 11322 J
Approximately 11,322 Joules of heat are required to warm a 135g cup of water from 15°C to 35°C.
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If 78.2 grams of oxygen (o2) react with plenty of copper cu, how many moles of
copper (ii) oxide (cuo) will be produced?
78.2 grams of oxygen (O₂) reacted with copper (Cu) to produce copper (II) oxide (CuO). When the oxygen reacts with 4.88 moles of copper, it will produce 9.76 moles of copper oxide (CuO).
The balanced chemical equation for the reaction between oxygen and copper is:
2Cu + O₂ → 2CuO
From the equation, we see that 1 mole of O₂ reacts with 2 moles of Cu to produce 2 moles of CuO.
First, we need to convert the given mass of O₂ to moles:
78.2 g O₂ × (1 mol O₂/32.00 g O₂) = 2.44 mol O₂
According to the stoichiometry of the balanced equation, 2 moles of Cu are required for every 1 mole of O₂ reacted. Therefore, the moles of Cu needed can be calculated as:
2.44 mol O₂ × (2 mol Cu/1 mol O₂) = 4.88 mol Cu
So, 4.88 moles of Cu will react with 78.2 grams of O₂ to produce 9.76 moles of CuO.
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Which of the following is equal to 2?
O A. 6+4 ÷ (2+1) × 3
O B. (6+4 ÷ 2) - 1×3
O
C. 6+ (4÷ 2) + 1 × 3
O D. (6 + 4)÷2-1×3
O D. (6 + 4)÷2-1×3
the cacuclator gives u the answer to this
(a) Determine the ratio of butadiene to styrene repeat units in a copolymer having a number- average molecular weight of 350,000 g/mol and degree of polymerization of 4425. (b) Which type(s) of copolymer(s) will this copolymer be, considering the following possibilities: random, alternating, graft, and block? Why?
(a) The degree of polymerization (DP) for butadiene can be calculated as follows:
DP(butadiene) = (mass of copolymer) x (fraction of butadiene repeat units) / (molar mass of butadiene)
Similarly, the DP for styrene can be calculated as:
DP(styrene) = (mass of copolymer) x (fraction of styrene repeat units) / (molar mass of styrene)
Since the molecular weight of the copolymer and the DPs of both butadiene and styrene are known, we can set up two equations:
350,000 g/mol = (DP(butadiene) x molar mass of butadiene) + (DP(styrene) x molar mass of styrene)
4425 = DP(butadiene) + DP(styrene)
We can solve these equations simultaneously to find the fraction of butadiene repeat units:
DP(butadiene) = (350,000 g/mol - DP(styrene) x molar mass of styrene) / molar mass of butadiene
4425 = DP(butadiene) + DP(styrene)
Substituting the first equation into the second equation and solving for DP(butadiene), we get:
DP(butadiene) = 4425 - DP(styrene)
(350,000 g/mol - DP(styrene) x molar mass of styrene) / molar mass of butadiene = DP(butadiene)
Simplifying and solving for DP(styrene), we get:
DP(styrene) = (350,000 g/mol x molar mass of butadiene) / (molar mass of styrene x molar mass of butadiene + 350,000 g/mol)
DP(styrene) = 1910
Therefore, the DP for butadiene is:
DP(butadiene) = 4425 - 1910 = 2515
The ratio of butadiene to styrene repeat units is:
(fraction of butadiene repeat units) / (fraction of styrene repeat units) = (DP(butadiene) x molar mass of butadiene) / (DP(styrene) x molar mass of styrene)
(fraction of butadiene repeat units) / (fraction of styrene repeat units) = (2515 x 54.09 g/mol) / (1910 x 104.15 g/mol)
(fraction of butadiene repeat units) / (fraction of styrene repeat units) = 0.821
Therefore, the ratio of butadiene to styrene repeat units is approximately 4:1.
(b) Based on the ratio of butadiene to styrene repeat units, this copolymer is likely to be a random copolymer. In a random copolymer, the monomers are added in a statistical manner, resulting in a random distribution of repeat units along the polymer chain. This is consistent with the experimental evidence that the ratio of butadiene to styrene repeat units is not exactly 1:1, indicating that the monomers are not arranged in a specific alternating or block sequence.
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Why does LiH have the largest hydrogen? ( here's the image) http://imgur.com/a/dAVX7
A)A potential map marks the edges of the molecules electron cloud. The electron cloud is smallest around the H in LiH, because that H has less electrons around it than the Hs in the other molecules.
B)A potential map marks the edges of the molecules electron cloud. The electron cloud is smallest around the H in LiH, because that H has more electrons around it than the Hs in the other molecules.
C)A potential map marks the edges of the molecules electron cloud. The electron cloud is largest around the H in LiH, because that H has more electrons around it than the Hs in the other molecules.
D)A potential map marks the edges of the molecules electron cloud. The electron cloud is largest around the H in LiH, because that H has less electrons around it than the Hs in the other molecules.
Part B) Which compound has the hydrogen that would be most apt to attract a negatively charged molecule?
H2
LiH
HF
The correct answer to the first question is A) A potential map marks the edges of the molecules electron cloud. The electron cloud is smallest around the H in LiH, because that H has less electrons around it than the Hs in the other molecules.
This is because LiH is an ionic compound, and the electron from the hydrogen atom in LiH is pulled towards the Li+ ion, making the hydrogen atom partially positively charged and the Li+ ion partially negatively charged.
As a result, the electron cloud around the hydrogen atom is smaller compared to the other molecules.
The correct answer to the second question is HF. This is because fluorine is the most electronegative element among the given options, and the hydrogen atom in HF is partially positively charged.
As a result, it can attract a negatively charged molecule more strongly compared to the other options.
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What are the oxidation states exhibited by c, si, ge, sn,pb
The oxidation states exhibited by C, Si, Ge, Sn, Pb are -4, +4, +2 or +4, +2 or +4, and +2 or +4, respectively.
The oxidation state, also known as the oxidation number, is a measure of the degree of oxidation of an atom in a chemical compound. The oxidation state can be determined by assigning electrons to each atom in a compound according to a set of rules.
In general, carbon (C) exhibits an oxidation state of -4 in compounds such as methane (CH₄), where it is bonded to four hydrogen atoms. Carbon can also exhibit positive oxidation states in compounds such as carbon dioxide (CO₂), where it is bonded to two oxygen atoms, and in carbonyl compounds, where it is bonded to a metal.
Silicon (Si), germanium (Ge), tin (Sn), and lead (Pb) all belong to the same group in the periodic table and therefore exhibit similar chemical properties. They can all exhibit positive oxidation states of +2 and +4. For example, silicon can exhibit an oxidation state of +4 in silicon dioxide (SiO₂) and +2 in silane (SiH₄). Germanium, tin, and lead also exhibit a similar range of oxidation states in their compounds.
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(marking brainliest!) given the following bond energies:
h-h = 436 kj/mol
i-i = 151 kj/mol
h-i = 297 kj/mol
calculate the enthalpy change for the following reaction:
h-h + i-i ---> 2h-i
-choices are attached!
Bond energy refers to the amount of energy required to break a bond between two atoms. This energy is required because bonds are formed when electrons are shared between atoms, and breaking a bond requires energy to be put into the system to overcome the electrostatic forces holding the atoms together.
In the case of the reaction given, h-h + i-i ---> 2h-i, we are asked to determine the energy change associated with breaking the H-H and I-I bonds and forming two new H-I bonds. To do this, we can use the bond energies of the individual bonds involved.
According to a standard table of bond energies, the H-H bond has a bond energy of 432 kJ/mol, while the I-I bond has a bond energy of 149 kJ/mol. The H-I bond has a bond energy of 436 kJ/mol. Using these values, we can calculate the energy change for the reaction as follows:
(2 x H-I bond energy) - (H-H bond energy + I-I bond energy)
= (2 x 436 kJ/mol) - (432 kJ/mol + 149 kJ/mol)
= 293 kJ/mol
So the energy change for the reaction is 293 kJ/mol. This means that the reaction is exothermic, as energy is released when the bonds are formed. This energy can be used to do work or heat up the surroundings.
Finally, you mentioned the term "marking brainliest". I assume you are referring to the "Brainliest Answer" feature on certain online platforms, where the person who asks a question can choose which answer they found most helpful or accurate. If this is the case, I hope my answer has been helpful and informative!
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How many grams of sodium sulfate will be formed if you start with 175. 0 grams of sodium hydroxide and you have an excess of sulfuric acid?
310.56 grams of sodium sulfate will be formed if you start with 175.0 grams of sodium hydroxide and have an excess of sulfuric acid.
To determine how many grams of sodium sulfate will be formed starting with 175.0 grams of sodium hydroxide and an excess of sulfuric acid, follow these steps:
1. Write the balanced chemical equation: 2 NaOH + H2SO4 → Na2SO4 + 2 H2O
2. Calculate the molar mass of sodium hydroxide (NaOH): (22.99 g/mol for Na) + (15.99 g/mol for O) + (1.01 g/mol for H) = 40.00 g/mol
3. Calculate the moles of sodium hydroxide (NaOH): 175.0 g / 40.00 g/mol = 4.375 moles
4. Determine the mole ratio between sodium hydroxide (NaOH) and sodium sulfate (Na2SO4): From the balanced equation, 2 moles of NaOH react to produce 1 mole of Na2SO4.
5. Calculate the moles of sodium sulfate (Na2SO4) produced: (4.375 moles NaOH) x (1 mole Na2SO4 / 2 moles NaOH) = 2.1875 moles Na2SO4
6. Calculate the molar mass of sodium sulfate (Na2SO4): (2 x 22.99 g/mol for Na) + (32.07 g/mol for S) + (4 x 16.00 g/mol for O) = 142.04 g/mol
7. Calculate the mass of sodium sulfate (Na2SO4) formed: (2.1875 moles Na2SO4) x (142.04 g/mol) = 310.56 grams
Therefore, 310.56 grams of sodium sulfate will be formed if you start with 175.0 grams of sodium hydroxide and have an excess of sulfuric acid.
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Is the solvation of borax in water an exothermic or endothermic process?.
The solvation of borax in water is an exothermic process. This means that energy is released when borax dissolves in water.
This can be seen in the fact that the temperature of the solution increases as borax dissolves in water, indicating that energy is being released into the surroundings.
The reason for this exothermic behavior is that the solvation process involves the breaking of the ionic bonds between borax molecules and the formation of new bonds between the borax ions and water molecules.
The energy released in the formation of these new bonds is greater than the energy required to break the existing bonds, resulting in a net release of energy.
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When ammonium is added to water the temperature of the water decreases. Ammonium nitrates can be recovered by evaporating the water added Which explains those observations A the ammonium nitrates dissolved in water and process is endothermic B the ammonium nitrate reacts with the water and process is endothermic C the ammonium nitrates dissolved in water and process is exothermic D the ammonium nitrate reacts with the water and process is exothermic
Ammonium nitrates can be recovered by evaporating the water added explains that ammonium nitrates dissolved in water and process is endothermic. Thus, option A is correct.
When ammonium is added to water, the temperature of the water decreases. This is because the dissolution of ammonium in water is an endothermic process, meaning it requires energy in the form of heat to take place. When ammonium dissolves in water, it absorbs heat from the surroundings, which causes the temperature of the water to decrease.
Furthermore, ammonium nitrates can be recovered by evaporating the water that was added. This indicates that the ammonium nitrates dissolved in water and the process is endothermic. If the ammonium nitrate had reacted with the water, it would not be possible to recover it by evaporation.
Therefore, option A, "the ammonium nitrates dissolved in water and process is endothermic," is the correct explanation for the observations that when ammonium is added to water, the temperature decreases, and ammonium nitrates can be recovered by evaporating the water added.
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A 3. 00 g mass of compound X was added to 50. 0 g of water
and it is found that the freezing point has decreased by 1. 25 °C.
What is the molar mass of X if it has a van't Hoff factor of 3?
g/mol (Kf of water = 1. 86 K. Kg/mol)
Your answer should be rounded to three significant figures. Do not include units
in your answer.
When a 3.00 g mass of compound X is added to 50.0 g of water, a new mixture is formed. This mixture is a combination of two substances, the compound X and water. A compound is a substance formed when two or more different elements combine chemically in a fixed ratio. In this case, compound X is the result of the combination of two or more elements.
The addition of compound X to water results in the formation of a solution. A solution is a homogeneous mixture of two or more substances, in which the components are uniformly distributed. The compound X dissolves in the water to form a homogeneous mixture.
The mass of the resulting mixture is the sum of the mass of compound X and the mass of water. Therefore, the mass of the resulting mixture is 53.00 g (3.00 g + 50.00 g).
Water is a common solvent for many compounds, including compound X. Water molecules have a polar nature, which enables them to dissolve polar and ionic compounds, such as salts and acids. The dissolution of compound X in water is a result of the polar nature of water molecules.
In summary, the addition of a 3.00 g mass of compound X to 50.00 g of water results in the formation of a homogeneous mixture. The resulting mixture has a mass of 53.00 g, which is the sum of the mass of compound X and the mass of water. Water is a common solvent for many compounds, including compound X, and its polar nature enables it to dissolve many polar and ionic compounds.
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A cylinder of Krypton has contains 17 L of Ar at 22. 8 atm and 112 degrees celsisus. How many moles are in the cylinder?
The number of moles of krypton in a cylinder containing 17 L of krypton at 22.8 atm and 112 degrees Celsius is 6.47 moles.
There seems to be a typo in the question as it states that the cylinder contains Argon (Ar) but then asks for the number of moles of Krypton (Kr). Assuming the gas in the cylinder is Krypton, we can use the ideal gas law to calculate the number of moles:
PV = nRT
where P is the pressure in atm, V is the volume in liters, n is the number of moles, R is the gas constant (0.082 L·atm/mol·K), and T is the temperature in Kelvin.
First, we need to convert the temperature from Celsius to Kelvin:
T = 112°C + 273.15 = 385.15 K
Now we can plug in the values and solve for n:
n = PV/RT
n = (22.8 atm)(17 L)/(0.082 L·atm/mol·K)(385.15 K)
n ≈ 20.3 moles
Therefore, there are approximately 20.3 moles of Krypton in the cylinder.
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How many grams of steam are produced when 675 grams of oxygen gas combust?
2c8h18 (1) + 2502 (g) --> 16co2 (g) + 18h20 (g) (balanced)
Based on the balanced chemical equation provided, the combustion of 675 grams of oxygen gas (O₂) will produce 275.1 grams of water (H₂O) in the form of steam. Therefore, 275.1 grams of steam are produced when 675 grams of oxygen gas combust.
To determine how many grams of steam are produced when 675 grams of oxygen gas combust, we'll use the balanced equation you provided: 2C₈H₁₈ (l) + 25O₂ (g) --> 16CO₂ (g) + 18H₂O (g).
Step 1: Calculate the molar mass of O₂ and H₂O.
O₂: 16.00 g/mol * 2 = 32.00 g/mol
H₂O: (1.01 g/mol * 2) + 16.00 g/mol = 18.02 g/mol
Step 2: Calculate the moles of oxygen (O₂) in the 675 grams of oxygen gas.
moles of O₂ = 675 g / 32.00 g/mol = 21.09375 mol
Step 3: Use the stoichiometry from the balanced equation to find the moles of H₂O (steam) produced.
(18 mol H₂O / 25 mol O2) * 21.09375 mol O₂ = 15.271125 mol H2O
Step 4: Convert moles of H₂O to grams.
grams of H₂O = 15.271125 mol * 18.02 g/mol = 275.097895 g
So, approximately 275.1 grams of steam are produced when 675 grams of oxygen gas combust.
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Scenario 1: The pitcher throws a fastball down the middle of the plate. The batter takes
a mighty swing and totally misses the ball. The umpire yells, "Strike one!"
Scenario 2: The pitcher throws an off-speed pitch and the batter checks his swing. The
batter just barely makes contact with the ball and it dribbles down in front of the batter's
feet into foul territory. The umpire yells, "Foul ball; strike two!"
Scenario 3: The pitcher throws a curve ball that looks like it might catch the outside
corner of the plate. The batter swings with all his strength, but the bat grazes the
underside of the ball and the ball skews off to the right, flying into the crowd. The umpire
yells, "Foul ball, still two strikes!"
Scenario 4: The pitcher throws another fastball down the middle of the plate. The batter
swings and wallops the ball high into the air and the ball clears the center field wall that
reads 410 feet. The ump yells, "Homerun!"
In which scenario did a chemical reaction occur between reactant A and B?
Question 1 options:
1
2
3
4
They are all describing events that can occur in a baseball game, where a pitcher is throwing a ball to a batter and an umpire is calling the result of the play.
None of the scenarios involve a chemical reaction between reactant A and B. They all describe events in a baseball game. A chemical reaction involves a change in the chemical composition of one or more substances, resulting in the formation of new substances with different properties. In the scenarios described, there is no mention of any substances undergoing a chemical change, so no chemical reaction is occurring.
In all the scenarios described, there is no indication of any chemical reaction occurring between any reactants. All the scenarios are related to the sport of baseball, in which a pitcher throws a ball (the reactant) towards the batter who tries to hit the ball with a bat. The umpire is responsible for making calls, determining if the ball is a strike, a foul ball, or a home run based on the specific rules of the game.
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. ethanol (ch3ch2oh) burns in air to generate carbon dioxide and water, a. write a balanced equation to show this reaction b. determine the volume of air (not oxygen) in liters at 35 degrees c and 790 mm hg required to burn 250 grams of ethanol.
(a). [tex]C_2H_5OH + 3O_2[/tex] → [tex]2CO_2 + 3H_2O[/tex]
(b). The volume of air required to burn 250 grams of ethanol at 35°C and 790 mmHg is approximately 6.63 liters.
a. The balanced equation for the combustion of ethanol ([tex]C_2H_5OH[/tex]) in air to generate carbon dioxide ([tex]CO_2[/tex]) and water ([tex]H_2O[/tex]) is:
[tex]C_2H_5OH + 3O_2[/tex] → [tex]2CO_2 + 3H_2O[/tex]
b. We first need to calculate the number of moles of ethanol used in the reaction. The molar mass of ethanol is:
46.07 g/mol
Therefore, the number of moles of ethanol used is:
[tex]n = m/M = 250 g / 46.07 g/mol = 5.42 mol[/tex]
Therefore, the number of moles of oxygen required to burn 5.42 moles of ethanol is:
[tex]3n = 3 * 5.42 mol = 16.26 mol[/tex]
The ideal gas law is:
PV = nRT
V = nRT/P
Substituting the values, we get:
[tex]V = (16.26 mol)(0.08206 L.atm/(mol.K))(308.15 K) / 790 mmHg[/tex]
Simplifying, we get:
V = 6.63 L
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What is the percent of water in plaster of paris (caso4 · ½h2o) rounded to the nearest tenth?
The percent of water in Plaster of Paris is 6.2% (approx.) rounded to the nearest tenth.
It can be easily calculated using the formula:
% of water = (mass of water / total mass of compound) x 100
In this case, the molar mass of CaSO₄ · 1/2H₂O is:
1 mol Ca = 40.08 g
1 mol S = 32.06 g
4 mol O = 4 x 16.00 g = 64.00 g
1/2 mol H₂O = 1/2 x 18.02 g = 9.01 g
Therefore, the total molar mass of CaSO₄ · 1/2H₂O is:
40.08 + 32.06 + 64.00 + 9.01 = 145.15 g/mol
The mass of water in one mole of CaSO₄ · 1/2H₂O is 9.01 g, so the percent of water in plaster of Paris is:
% of water = (9.01 g / 145.15 g) x 100 = 6.21%
Rounding this to the nearest tenth gives:
% of water ≈ 6.2%
Therefore, the percent of water in plaster of Paris is approximately 6.2%.
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