The heat of fusion AH, of ammonia (NH) is 5.6 kJ/mol. Calculate the change in entropy AS when 971. g of ammonia melts at - 78.0 °C. Be sure your answer contains a unit symbol and the correct number of significant digits. д х 5 ?
Answers
The change in entropy when 971 g of ammonia melts at -78.0 °C is 1636 J/K .
How to calculate Change in entropy?
To calculate the change in entropy (ΔS) when 971 g of ammonia (NH₃) melts at -78.0 °C, you can use the following formula:
ΔS = (\(q_{p}\)) / T
Where \(q_{p}\) is the heat absorbed during melting (in J/mol), and T is the temperature in Kelvin.
First, let's convert the given mass of ammonia to moles:
m = 971 g
molar mass of NH₃ = 14.01 (N) + 3 × 1.01 (H) = 17.03 g/mol
moles of NH₃ = (971 g) / (17.03 g/mol) = 57.0 mol
Next, convert the heat of fusion ΔH from kJ/mol to J/mol:
ΔH = 5.6 kJ/mol × 1000 J/1 kJ = 5600 J/mol
Now, calculate the heat absorbed during melting (q_p):
\(q_{p}\) = (57.0 mol) × (5600 J/mol) = 319200 J
Convert the temperature from °C to Kelvin:
T = -78.0 °C + 273.15 = 195.15 K
Finally, calculate the change in entropy (ΔS):
ΔS = (\(q_{p}\)) / T = (319200 J) / (195.15 K) = 1636 J/K
The change in entropy when 971 g of ammonia melts at -78.0 °C is 1636 J/K (with three significant digits).
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Related Questions
Identify Which device can store sound
information?
Answers
Answer:
Explanation: D
3. How many atoms of hydrogen do 3.575 mol of hydrogen sulfide contain?
Answers
Answer:
4.3043x10^24
Explanation:
Atoms(H) = (3.575 mol H2S/1)(2 mol H/1mol H2S)(6.02x10^23/1molH)
Simple stoicheometry problem. Sorry for taking so long, took Chem sophomore year, its been a while
At a constant pressure, a 10.0 L volume of gas is cooled from 546 K to 273 K. What will be the final volume of this gas, assuming no liquefying occurs?
Answers
Answer:
5.0 L
Explanation:
We must recall that pressure is only held constant when referring to Charles law. We then put down the parameters given in the question.
Initial volume V1= 10.0 L
Initial temperature T1= 546 K
Final temperature T2= 273 K
Final volume V2= the unknown
From the statement of Charles law;
V1/T1 = V2/T2
V1T2= V2T1
V2= V1T2/T1
V2= 10.0 × 273/ 546
V2= 5.0 L
Therefore, the new (final) volume is 5.0 L
Answer:
Since the temperature is halved, the volume will also be halved.
The final volume is 5.0 L
Explanation:
Step 1: Data given
The pressure is constant
The initial volume of the gas = 10.0 L
The initial temperature = 546 K
The temperature is cooled to 273 K
Step 2: Calculate the final volume
V1/T1 = V2/T2
⇒with V1 = the initial volume = 10.0L
⇒with T1 = the initial temperature = 546 K
⇒with V2 = the final volume = TO BE DETERMINED
⇒with T2 = the final temperature = 273 K
10.0 L / 546 K = V2 / 273 K
V2 = (10.0 L * 273 K) / 546 K
V2 = 5.0 L
Since the temperature is halved, the volume will also be halved.
The final volume is 5.0 L
Wind power was first used in the 1970s.
A. true
B. false
Answers
Answer:
B. false
Explanation:
Answer:
B (false)
Explanation:
Because, the earliest recorded evidence of wind energy being used dates to around 5000 BC in Egypt, where the sail was invented to catch the wind and propel boats along the River Nile
What are the cons of using a cup made of steel?
Answers
Answer:
1. Sometimes there’s a metallic taste to the water
2. The water becomes hot if left in your car or outdoors in hot weather
3. Bottle can dent if dropped
4. Paint sometimes peels off exterior of metal bottles
5. Metal water bottles lined with a resin lining also leach BPA. Do not get a bottle with what appears to be a “colored” lining of any kind.
Explanation:
Answer:
Steel feels cold, can dent, and is heavy. Sometimes it has a strange taste. Steel can also stain with use.
Explanation:
Hope this helps! :)
Convert to scientific notation : 520,000,000
Answers
Answer:
5.2 x 10^8
Explanation:
Answer:
5.2x10^8
Explanation:
hope this helped
what name is given ta a metal strip dipped into a solution of salt
Answers
Answer:
metal oxide
Explanation:
because anything that reacts with oxygen is oxide
what is the formula for the compound made from beryllium and bromine?
Answers
Beryllium bromide is a compound formed by the combination of beryllium and bromine atoms. Its chemical formula is BeBr₂, indicating that each molecule of beryllium bromide contains one beryllium atom and two bromine atoms.
Beryllium has a 2+ charge, while bromine has a 1- charge. To achieve electrical neutrality, two bromine atoms are needed to balance the charge of one beryllium atom. Beryllium bromide is an ionic compound, characterized by the electrostatic attraction between the positively charged beryllium cation and the negatively charged bromide anions.
It is a white crystalline solid that is highly soluble in water. Beryllium bromide is primarily used in organic synthesis as a Lewis acid catalyst and in some industrial applications. Due to the toxicity of beryllium compounds, including beryllium bromide, proper safety precautions must be taken when handling or working with this substance.
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Which of the compounds below will ionize in water? Check all that apply. (PLEASE INCLUDE AN EXPLANATION OF YOUR PROCESS!)
A) H2SO4
B) NH3
C) NaCl
D) SO2
E) MgBr2
Answers
The compounds that are able to ionize completely in water are;
Sulfuric acidSodium chloridemagnesium bromideWhat is an ionic compound?We define an ionic compound as a compound that is able to dissolve in water. We know that the dissolution occurs because the the molecules of water is able to surround the ions in the compound and then pull them apart.
This implies that we have to start looking at the compounds that are able to be dissolved in water quite easily by the process of hydration in which the ions in the compound are pulled apart by water. These, like I said are the compounds that we call ionic compounds.
The compounds that we look out for are the acids and other ionic compounds and we can see that they are part of the list that we can see in the question listed above.
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Calculate the number of moles in the following samples.
a. 41.4g Al(OH)3
Answers
Answer:
0.531 mol Al(OH)3
an azeotrope is a mixture that has the same composition in the liquid phase than the gas phase . therefore, an azeotropic mixture can be separated by distillation.
Answers
An azeotrope is a composition that has the similar components in the liquid phase as compared to the gas phase . therefore, an azeotropic compositions cannot be separated by distillation.
It is not separated by the distillation or fractional process due to the reason of the when the azeotrope mixture is boiled, the gaseous vapor has the similar proportions of constituents or the components as the unboiled mixture.
It can only be separated by azeotropic distillations. This method is also well known by the AD process.
It is a method to break the azeotropes with the help of various mixture of solvent , or separating agent it forms heterogeneous azeotropes.
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please help question is in photo will give brainiest
Answers
Answer:
D
Explanation:
A buildup of charges in an object is called
Answers
Answer:
Static Electricity
Explanation:
Answer:
static electricity
Explanation:
HELP ASAP SCIENCE GIVING BRAINLIST FOR CORRECT
Answers
Answer:
Jellyfish :)
Have an amazing day!!
Please rate and mark brainliest!!
Calculate the pH at 25^oC of a 0.19 M solution of potassium butanoate (KC, H,CO). Note that butanoic acid (HC, H,Co,) is a weak acid with apk, of 4.82.
Answers
The pH at 25^oC of a 0.19 M solution of potassium butanoate (KC, H,CO approximately 2.96.
Given that potassium butanoate, KC, H, CO, is a weak acid with pKa of 4.82 and a solution of 0.19 M concentration is provided, we can calculate the pH at 25°C as follows:
\(Kw = Ka × Kb\)
Kb = Kw/Ka
Where, Kw = 10^-14 (at 25°C)
Ka = 10^-pKa
We have the pKa value of potassium butanoate as 4.82.
∴ Ka = 10^-4.82
= 1.35 × 10^-5mol/L
Now, Kb = Kw/Ka
= 10^-14/1.35 × 10^-5
= 7.41 × 10^-10M
At 25°C, we can calculate the concentration of H+ ions by using the expression given below:
Ka = [H+] × [A-] / [HA]
[H+] = Ka × [HA] / [A-]
= (1.35 × 10^-5) × √0.19 / 0.19
= 1.1 × 10^-3M
Thus, pH = -log[H+]= -log(1.1 × 10^-3)≈ 2.96
Hence, the pH of 0.19 M potassium butanoate solution at 25°C is approximately 2.96.
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Plzzzzzzzzz help whole slide
Answers
Answer: in order, cellular respiration, carbon dioxide, agricultural, methane, digestion, volcanic activity, eruption
Explanation:
its hard to explain why these things are thing you will have to memorize at first and then as you get later into science, you will learn about chlorophyll and mitochondria, and all sorts of fun things!
The figure shows a tank with two immiscrble liquid is andar. The vacuum gauges hown indicates a reading of 17.17KPo Determire a) Absolut pressure at point [ b) Relative pressure atpoint F, with respect to the ain in the tank; that is, if said air were the environrent of the instrument of measurerest Patm =77.17[kpa]g=81 g=9.81[m(s2] Environmental temperatice: 20[∘C] δ=0.68δ=0.8
Answers
a) The absolute pressure at point B cannot be determined based on the given information.
b) The relative pressure at point F, with respect to the air in the tank, is also indeterminable with the provided information.
a) The absolute pressure at point B cannot be determined because the information about the liquid levels or the densities of the liquids in the tank is not provided.
The absolute pressure depends on the height of the liquid column and the density of the liquid, which are missing from the given data. Without this information, it is not possible to calculate the absolute pressure at point B.
b) The relative pressure at point F, with respect to the air in the tank, is also indeterminable. To calculate the relative pressure, we need to know the absolute pressure at point F and subtract the atmospheric pressure.
However, the absolute pressure at point F is not given, so we cannot determine the relative pressure. Additionally, the value of atmospheric pressure (Patm) provided is not relevant to calculating the relative pressure at point F.
In order to determine the absolute pressure at point B or the relative pressure at point F, we would need additional information such as the liquid levels in the tank, the densities of the liquids, and possibly the atmospheric pressure at point F.
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Answer for number 9 i need it asap thank you
Answers
Answer:
a) Trichloromethyl
b) Trinitrogen Pentoxide
c) Carbogen
Explanation:
which system has a higher entropy? (a) 1 g of solid au at 1064k of 1 g of liquid au at 1064k
Answers
The system with a higher entropy would be 1 g of liquid gold at 1064 K, as it has a more disordered arrangement of particles than 1 g of solid gold at the same temperature.
The system with higher entropy would be the one with more disorder or randomness. Entropy is a measure of the number of possible arrangements of the system's particles or molecules, and it increases with increasing disorder.
In this case, we can consider the entropy of 1 g of solid gold at 1064 K versus the entropy of 1 g of liquid gold at the same temperature. At the melting point of gold, 1064 K, both the solid and liquid phases can coexist in equilibrium.
While both phases have the same temperature, the liquid phase has higher entropy than the solid phase. This is because the particles in the liquid phase are less ordered and more randomly distributed than those in the solid phase, which are arranged in a regular crystalline structure.
Therefore, the system with a higher entropy would be 1 g of liquid gold at 1064 K, as it has a more disordered arrangement of particles than 1 g of solid gold at the same temperature.
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What kind of exercise does not require the use of oxygen to metabolize energy? strength aerobic stretching anaerobic
Answers
Answer:
See Below
Explanation:
'an aerobic ' means it does not use oxygen
Answer:
anaerobic
Explanation:
Explain why beryllium is produced when potassium is heated with beryllium
chloride.
You should refer to reactivity in your answer.
Answers
Explanation:
The more reactive element replaces less reactive element during chemical reaction.
Since, potassium is more reactive than beryllium. When potassium reacts with beryllium choride, it replaces beryllium and forms potassium chloride and produces beryllium.
Beryllium is produced due to the fact that the more reactive element in the reaction would have to take over the element that is less reactive.
The chemical reaction of Potassium and Beryllium chloride
In this reaction the element that is more reactive is potassium. When the reaction takes place it would take over and replace beryllium due to this quality.
Hence beryllium chloride would become potassium chloride from the resulting reaction.
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Aluminum has metallic bonds between its atoms. Which statement BEST describes the
valence electrons in aluminum?
are exchanged with nonmetal atoms
are exchanged with other metal atoms
are localized and stay between metal atoms
are delocalized and move between metal atoms
Look at picture
ASAP please will mark as brainlist don’t got much time
Answers
Answer:
are delocalized and move between metal atoms
Explanation:
As the problem says, aluminum has metallic bonds. The main characteristic of metallic bonds is that the electrons are free to move between the metal ions (they are delocalized), thus being responsible for the good electrical conductivity of metals.
Polyelectrolytes are typically used to separate oil and water in industrial applications. The separation process is dependent on controlling the pH. Fifteen (15) pH readings of wastewater following these processes were recorded. Is it reasonable to model these data using a normal distribution? 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 10.0 10.5 7.6 11.4 11.4 10.0 Yes, it passes the "fat pencil" test. Therefore, a normal distribution is a reasonable model. No, it does not pass the "fat pencil" test. Therefore, a normal distribution is not a reasonable model. O Yes, it passes the "fat pencil" test. Therefore, a normal distribution is not a reasonable model. O No, it does not pass the "fat pencil" test. Therefore, a normal distribution is a reasonable model.
Answers
No, it does not pass the "fat pencil" test. Therefore, a normal distribution is not a reasonable model. Option B is the correct answer.
The "fat pencil" test is a quick visual check to determine if a dataset can be reasonably approximated by a normal distribution. In this case, the pH readings of wastewater show a significant deviation from a normal distribution. The presence of several low pH values (1.0) and a few high pH values (10.0, 10.5, 11.4) indicate a non-normal distribution with skewness and potential outliers. Therefore, it is not reasonable to model these data using a normal distribution.
Option B is the correct answer.
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the half-life of radioactive carbon-14 is 5730 years. if the 14c level in a sample of organic matter has been reduced to 0.200% of its original value, approximately how much time has passed? radioactive decay follows first-order kinetics. the half-life of radioactive carbon-14 is 5730 years. if the 14c level in a sample of organic matter has been reduced to 0.200% of its original value, approximately how much time has passed? radioactive decay follows first-order kinetics. 1,650 years 2,870,000 years 9,220 years 29,900 years 51,400 years
Answers
Approximately 9,220 years have passed since the 14C level in the sample of organic matter has been reduced to 0.200% of its original value.
Radioactive decay of carbon-14 follows first-order kinetics, which means the decay rate is proportional to the amount of remaining radioactive material.
The half-life of carbon-14 is 5730 years, which is the time it takes for half of the radioactive carbon-14 atoms in a sample to decay.
To determine the time elapsed, we can use the formula for the decay of a first-order reaction:
t = (ln(N₀/N)) / k,
where t is the time elapsed, N₀ is the initial amount, N is the final amount (0.200% of the original value), and k is the decay constant. The decay constant (k) can be calculated as ln(2) divided by the half-life (5730 years).
Substituting the values into the equation, we can solve for t. The result is approximately 9,220 years.
Therefore, approximately 9,220 years have passed since the 14C level in the sample of organic matter has been reduced to 0.200% of its original value.
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Under what conditions does the Ideal Gas Law not apply and gases are considered real? Check all that apply. High pressure low pressure high temperature low temperature.
Answers
Considering the definition of ideal gas and gas laws, The Ideal Gas Law not apply and gases are considering real under conditions of high pressure low pressure.
Definition of ideal gasAn ideal gas is a theoretical gas that is considered to be composed of randomly moving point particles that do not interact with each other.
In other words, an ideal gas is defined as one in which all collisions between atoms or molecules are perfectly elastic and in which there are no intermolecular attractive forces, so they do not interact with each other.
Gases in general are ideal when they are at high temperatures and low pressures.
Definition of gas lawsOn the other hand, the gas laws are a set of chemical and physical laws that allow us to determine the behavior of gases in a closed system. The parameters evaluated in these laws are pressure, volume, temperature, and moles.
Summary
The Ideal Gas Law not apply and gases are considering real under conditions of high pressure low pressure.
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Answer:
its A and D
Explanation:
The efficiency ratio for a steel specimen immersed in a phosphating tank is the weight of the phosphate coating divided by the metal loss (both in mg/ft 2
). Table gave the accompanying data on tank temperature (x) and efficiency ratio (y). Construct a scatter diagram to represent the relationship between temperature (x) and efficiency ratio (y) on a graph paper. Analyze the relationship between these two parameters by computing the linear regression equation using least square method. Find the correlation coefficient and coefficient of determinations.
Answers
The linear regression equation for the relationship between temperature (x) and efficiency ratio (y) is y = a + bx, where y represents the efficiency ratio and x represents the tank temperature.
In order to analyze the relationship between temperature and efficiency ratio, we can use the method of linear regression. Linear regression helps us determine the equation of a straight line that best fits the given data points. This equation allows us to estimate the efficiency ratio for any given tank temperature.
By using the least squares method, we calculate the values of the regression coefficients a and b. The coefficient a represents the y-intercept of the line, while the coefficient b represents the slope of the line. These coefficients allow us to determine the equation of the line that represents the relationship between temperature and efficiency ratio.
Once we have the regression equation, we can calculate the correlation coefficient and coefficient of determination. The correlation coefficient, denoted by r, measures the strength and direction of the linear relationship between the two variables. It ranges between -1 and 1, where values close to -1 or 1 indicate a strong linear relationship. The coefficient of determination, denoted by \(r^2\), represents the proportion of the total variation in the efficiency ratio that can be explained by the variation in temperature.
By analyzing the scatter diagram, we can visually observe the trend between temperature and efficiency ratio. The linear regression equation and the correlation coefficient provide quantitative measures to further understand and interpret the relationship between these two parameters.
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Given the pKa’s for H2CO3: pKa1 = 6.35; pKa2=10.33, what is the pKb1 of CO32- (Kb1 is the equilibrium constant of the reaction: CO32- + H2O ⇌ HCO3- + OH-)?
(A) 14.00
(B) 10.33
(C) 3.67
Answers
To determine the pKb1 of CO32-, we can use the relationship between pKa and pKb for conjugate acid-base pairs:
pKa + pKb = pKw
where pKw is the ionization constant of water, which is approximately 14. Therefore, we can rearrange the equation to solve for pKb:
The pKb value represents the negative logarithm of the equilibrium constant (Kb) for the reaction of a base with water. In this case, we are interested in the equilibrium reaction between CO32- and water, which can be represented as CO32- + H2O ⇌ HCO3- + OH-.
By utilizing the relationship pKa + pKb = pKw, we can rearrange the equation to solve for pKb. Given that pKa1 of H2CO3 is 6.35, we subtract this value from pKw (approximately 14) to obtain pKb1
pKb = pKw - pKa
pKb1 = 14 - 6.35 = 7.65
Since none of the given answer choices matches the calculated value, it seems there might be an error or omission in the available options. Please double-check the answer choices provided or refer to additional information to obtain the correct pKb1 value for CO32-.
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What is the purpose of chemistry lab?(solution)
Answers
1. Some reactions will present an actual yield lower than the theoretical yield, and this can occur due to many situations, a couple of the reasons why that we can list is that some reactions don't have the reactants actually reacting to form the products, and another reason why is the loss of reactants in the process for many possible situations.
4. According to the solubility curve, if we have 30 grams of NH4Cl at 50°C, the reaction will be unsaturated
a mineral sample from rock unit c has 50,000 atoms of
uranium-235 and 150000 atoms of lead 207
Answers
To calculate the ratio of uranium-235 to lead-207 atoms in the mineral sample, we can use the atomic masses and the concept of radioactive decay.
The ratio of uranium-235 to lead-207 atoms in the mineral sample is 1:3.The atomic mass of uranium-235 (U-235) is approximately 235 atomic mass units (amu), while the atomic mass of lead-207 (Pb-207) is approximately 207 amu.
Given:
Number of uranium-235 atoms = 50,000
Number of lead-207 atoms = 150,000
To find the ratio, we divide the number of uranium-235 atoms by the number of lead-207 atoms:
Ratio = Number of uranium-235 atoms / Number of lead-207 atoms
Ratio = 50,000 / 150,000
Simplifying the ratio:
Ratio = 1/3
Therefore, the ratio of uranium-235 to lead-207 atoms in the mineral sample is 1:3.
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What is the molar concentration a a 12 % sodium chloride solution (MW 58.5)
Answers
The molar concentration of a 12% sodium chloride solution is approximately 2.05 M.
To determine the molar concentration of a 12% sodium chloride solution, we need to convert the given percentage concentration into molarity.
First, we need to understand that the percentage concentration refers to the mass of the solute (sodium chloride) relative to the total mass of the solution.
In this case, a 12% sodium chloride solution means that there are 12 grams of sodium chloride in 100 grams of the solution.
To convert this into molar concentration, we need to consider the molar mass of sodium chloride, which is 58.5 g/mol.
We can start by calculating the number of moles of sodium chloride in 12 grams:
Moles of sodium chloride = mass of sodium chloride / molar mass of sodium chloride
Moles of sodium chloride = 12 g / 58.5 g/mol = 0.205 moles
Next, we calculate the volume of the solution in liters using the density of the solution. Since the density is not provided, we assume a density of 1 g/mL for simplicity:
Volume of solution = mass of solution / density
Volume of solution = 100 g / 1 g/mL = 100 mL = 0.1 L
Finally, we calculate the molar concentration (Molarity) by dividing the number of moles by the volume in liters:
Molar concentration = moles of solute / volume of solution
Molar concentration = 0.205 moles / 0.1 L = 2.05 M
Therefore, the molar concentration of a 12% sodium chloride solution is approximately 2.05 M.
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