Answer:
Explanation:
We can use the formula:
q = mcΔT
where q is the heat absorbed, m is the mass, c is the specific heat, and ΔT is the change in temperature.
Given:
specific heat of iron (c) = 0.449 J/g°C
initial temperature (T1) = 24.0°C
final temperature (T2) = 82.1°C
heat absorbed (q) = 948.0 J
Substituting the given values into the formula, we get:
q = mcΔT
948.0 J = m(0.449 J/g°C)(82.1°C - 24.0°C)
948.0 J = m(0.449 J/g°C)(58.1°C)
m = 948.0 J ÷ (0.449 J/g°C × 58.1°C)
m = 33.1 g
Therefore, the mass of the iron piece is 33.1 g (to three significant figures)
How does the frequency of a string affect its wavelength?
Answer:
as the frequency goes down, the speed goes down by the same factor, and so the wavelength doesn't change.
Explanation:
Answer: as the frequency goes down, the speed goes down by the same factor, and so the wavelength doesn't change.
Explanation:
What amount of heat, in kJ, is required to vaporize 181.20 g of ethanol (C₂H₅OH)? (∆Hvap = 43.3 kJ/mol)
The amount of heat required to vaporize 181.20 g of ethanol would be 170.1 kJ.
Heat of vaporizationUsing the formula:
Q = n ∆Hvap
where:
Q is the amount of heat required to vaporizen is the number of moles of the substance∆Hvap is the molar heat of vaporization.Moles of 181.20 g of ethanol = 181.20 g / 46.07 g/mol = 3.933 mol
Substituting the values:
Q = 3.933 mol x 43.3 kJ/mol = 170.1 kJ
In other words, the amount of heat required to vaporize 181.20 g of ethanol is 170.1 kJ.
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A 0.4 kg piece of ice at -10 ∘C is dropped from a height h. Upon impact, 3.0 % of its kinetic energy is converted into heat energy. If the impact transforms all of the ice into water that has a final temperature of 0 ∘C , find h .
The height of fall of the ice is determined as 313.25 m.
What is the heat energy of the ice?The total heat energy of the ice during the fall is calculated as follows;
Q = ml + mcΔT
where;
c is the specific heat of waterl is latent heat of fusionΔT is change in temperatureQ = 334000 x 0.4 + 0.4 x 4200 x (10)
Q = 150,400 J
The energy converted into potential energy is calculated as;
3%K.E = 150,400 J
0.03K.E = 150,400 J
K.E = 5,013,333.33 J
¹/₂mv² = 5,013,333.33 J
v = √(2 x 5,013,333.33)/(0.4)
v = 5,006.67 m/s
The height of fall is calculated as;
h = √2gh
h = √(2 x 5,006.67 x 9.8)
h = 313.25 m
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Given the following reaction:
2C₂H₂(g) + 5O₂(g) → 4CO₂(g) + 2H₂O(g) ∆H = -2511.6 kJ
What is the energy change when 7.76 g of C₂H₂ react with excess O₂?
Chemical reactions nearly always include a change in energy between the products and reactants.
Thus, Energy is released when chemical bonds are created and is released when chemical bonds are destroyed.
The overall energy of a system, however, must remain constant according to the Law of Conservation of Energy, and chemical reactions frequently absorb or release energy in the form of heat, light, or both.
The difference in the amounts of chemical energy that are stored in the products and reactants accounts for the energy change in a chemical reaction. Enthalpy refers to the system's heat content or stored chemical energy.
Thus, Chemical reactions nearly always include a change in energy between the products and reactants.
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You have 20.7 grams of water at -25.34 °C. You want to warm it to 155.0 °C. Use the information below to calculate how much heat this will require.
Csolid = 2.09 J/(g·°C)
ΔHfus = 333 J/g
Cvapor = 2.03 J/(g·°C)
ΔHvap = 2260 J/g
Answer:
Cvapor = 2.03 J/(g·°C)heu
The 500 cm³ of a pas enclosed in a container under a pressure of 580 mm of Hg. If the volume is reduced to 300 cm³ what will be the pressure then?
Answer:
The answer is 966.67 mm of Hg.
Explanation:
To solve this problem, we can use Boyle's Law which states that the pressure of a gas is inversely proportional to its volume when the temperature and the amount of gas are kept constant. The formula for Boyle's Law is:
P1V1 = P2V2
where P1 is the initial pressure, V1 is the initial volume, P2 is the final pressure, and V2 is the final volume.
Using the given values:
P1 = 580 mmHg
V1 = 500 cm³
V2 = 300 cm³
We can solve for P2:
P1V1 = P2V2
580 mmHg x 500 cm³ = P2 x 300 cm³
290,000 mmHg·cm³ = P2 x 300 cm³
P2 = 290,000 mmHg·cm³ / 300 cm³
P2 = 966.67 mmHg (rounded to the nearest hundredth)
Therefore, the pressure when the volume is reduced to 300 cm³ is approximately 966.67 mmHg.
a solution is made by mixing 100 ml of ethanol and 200 mL of water identified the solute of solvent of the solution and calculate the total volume of the solution
The solution has a total volume of 300 mL and is composed of 100 mL of ethanol (the solute) and 200 mL of water (the solvent).
Does a solution form when 50 mL of ethanol and 50 mL of water are combined?Less than 100 ml will result from mixing 50 ml each of ethanol and water in an equal ratio. This happens because ethanol molecules, which are smaller than those of water, may fit inside big water molecules. As a result, the alcohol content in a 250 mL mix of water and alcohol is 60%.
The combined volumes of the ethanol and water make up the total volume of the solution, which is:
Total volume = 100 mL + 200 mL = 300 mL
Therefore, the solution is made up of 100 mL of ethanol (the solute) and 200 mL of water (the solvent), with a total volume of 300 mL.
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Will we ever send humans to another planet? Most believe that if we were to travel to another planet, Mars would be the best option. Which of these would be a potential problem associated with travel to another planet?
Question 1 options:
we already know everything about Mars
no astronauts would ever volunteer for this mission
Mars has such a high gravity that it would crush humans and our spacecraft
the extended time for humans to be in space
A potential problem associated with travel to another planet is : the extended time for humans to be in space.
What is the potential problem associated with travel to another planet?It is highly likely that humans will travel to another planet, and Mars is currently considered the most viable option for human exploration. However, there are many potential problems associated with this endeavor, and one of the major issues is the extended time that humans would need to spend in space.
Traveling to Mars would take several months, and once there, astronauts would need to spend significant amount of time on planet before returning to Earth. This means that they would be exposed to high levels of radiation and would need to find ways to survive in harsh and unforgiving environment.
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What is the family puzzle worksheet answer? Please make the pedigree and give me the answers
Interpreting Data:
Joshua's parents must be heterozygous carriers for cystic fibrosis (Nn).Bella's parents must be homozygous for the normal allele (NN).How to analyze family pedigrees?Predicting:
Joshua's brother has a 50% chance of being a carrier for cystic fibrosis (Nn) and a 50% chance of having the normal genotype (NN). This is because Joshua's parents are both carriers, so each of their children has a 50% chance of inheriting the recessive allele.
Communicating:
As a genetic counselor, information about many generations of a family is needed to draw conclusions about a hereditary condition because traits are passed down from generation to generation. By studying the family history, we can identify patterns of inheritance and determine the likelihood that a person has inherited a certain trait. This information can help us make informed decisions about genetic testing and treatment options.
Additionally, knowing the family history can help us determine the risk of passing on a genetic condition to future generations.
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Image transcribed and complete question:
Family Puzzle
Problem
A husband and wife want to understand the probability that their children might inherit cystic fibrosis. How can you use the information in the labeled Case Study to predict the probability?
Skills Focus
interpreting data, predicting
Materials
12 index cards
scissors marker
Procedure
1. Read the Case Study. In your notebook, draw a pedigree that shows all the family members. Use circles to represent the females, and squares to represent the males. Shade in the circles or squares representing the individuals who have cystic fibrosis.
2. You know that cystic fibrosis is controlled by a recessive allele. To help you figure out Joshua and Bella's family pattern, create a set of cards to represent the alleles. Cut each of six index cards into four smaller cards. On 12 of the small cards, write N to represent the dominant normal allele. On the other 12 small cards, write n for the recessive allele.
Case Study:
Joshua and Bella
• Joshua and Bella have a son named lan. lan has been diagnosed with cystic fibrosis.
⚫ Joshua and Bella are both healthy.
• Bella's parents are both healthy.
• Joshua's parents are both healthy. • Joshua's sister, Sara, has cystic fibrosis.
Analyze and Conclude
Write your answers in the spaces provided.
1. Interpreting Data What were the genotypes of Joshua's parents? What were the genotypes of Bella's parents?
2. Predicting Joshua also has a brother. What is the probability that he has cystic fibrosis? Explain.
3. Communicating Imagine that you are a genetic counselor. A couple asks why you need information about many generations of their families to draw conclusions about a hereditary condition. Write an explanation you can give to them.
More to Explore
Review the pedigree that you just studied. What data suggest that the traits are not sex-linked? Explain.
aHow does the electronic configuration of a sodium cation differ from that of a sodium atom?
Answer:
Atomic number of sodium is 11
Electronic configuration of a sodium atom :
1s² 2s² 2p⁶ 3s¹Since sodium has one electron in its outermost shell, Therefore, sodium can easily donate it's one electron. As the result it becomes sodium cation with + 1 charge.
Electronic configuration of a sodium cation,[tex] \: \sf ({Na}^{+1}) [/tex]
1s² 2s² 2p⁶In case of sodium cation, it has fully filled electronic configuration.
Cations - Atoms that carry postive charge are called cations. Cations are formed when an atom loses its electron.
For example : [tex]\sf {Na}^{+} [/tex]
Anions - Atoms that carry negative charge are called anions. Anions are formed when an atom gains a electron.
For example : [tex]\sf {Cl}^{-} [/tex]
In a reaction between vinegar and antacid tablets, the antacid is the limiting reagent. cm of gas. At constant pressure and temperature, three tablets produce 600 cm³ What volume will four tablets produce? 300 cm³ 600 cm³ 800 cm³ 3 1,200 cm³ 3
If in a reaction between vinegar and antacid tablets, the antacid is the limiting reagent. cm of gas. At constant pressure and temperature, three tablets produce 600 cm³ . The volume that four tablets will produce is: C. 800 cm³.
What volume will four tablets produce?Since the antacid is the limiting reagent, the amount of gas produced will be directly proportional to the number of tablets used.
We know that three tablets produced 600 cm³ of gas. Therefore, we can set up a proportion:
3 tablets produce 600 cm³ of gas
4 tablets produce x cm³ of gas
To solve for x, we can use cross-multiplication:
3 tablets × x cm³ of gas = 4 tablets × 600 cm³ of gas
3x = 2400
x = 800 cm³
Therefore the answer is C. 800 cm³.
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What is the chemical formula for the ionic compound barium iodide?
The chemical formula for the ionic compound barium iodide is [tex]BaI_2[/tex] .
Barium iodide is composed of one barium ion (Ba2+) and two iodide ions (I-), which together form a neutral compound. Barium iodide is a white crystalline solid with a high melting point and is soluble in water. It is commonly used in the manufacture of photographic paper and in the production of cathode ray tubes for televisions and computer monitors.
Barium iodide has a variety of other uses, including in medicine as a contrast agent for X-ray imaging and in the synthesis of organic compounds.
The compound has several different crystal structures, including hexagonal and cubic, and can be prepared by reacting barium carbonate with hydroiodic acid. Overall, barium iodide is an important and versatile compound with a range of practical applications.
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Explain why group 8 elements of the periodic table are referred to as group 0
Answer: They have eight outer electrons.
Explanation: They don't need any more electrons to be added to them and can't give out any electrons to other groups. They have a complete outer shell.
Calculate the volume of C2H2 that is collected over water at 23 ∘C by a reaction of 1.52 g of CaC2 if the total pressure of the gas is 751 torr. (The vapor pressure of water is 21.07 torr .)
The volume of C₂H₂ that is collected over water at 23 ∘C by the reaction of 1.52 g of CaC₂ is 0.61 L
How do i determine the volume of C₂H₂ collected?First, we shall determine the mole of CaC₂ that reacted. Details below:
Mass of CaC₂ = 1.52 g Molar mass of CaC₂ = 64 g/mol Mole of CaC₂ =?Mole = mass / molar mass
Mole of CaC₂ = 1.52 / 64
Mole of CaC₂ = 0.024 mole
Next, we shall determine the mole of C₂H₂. obtained. Details below:
CaC₂ + 2H₂O -> C₂H₂ + Ca(OH)₂
From the balanced equation above,
1 mole of CaC₂ reacted to produced 1 mole of C₂H₂
Therefore,
0.024 mole of CaC₂ will also react to produce 0.024 mole of C₂H₂
Finally, we shall determine the volume of C₂H₂ collected. This is shown below:
Temperature (T) = 23 °C = 23 + 273 = 296 KVapor pressure = 21.07 torrPressure of dry gas (P) = 751 - 21.07 = 729.93 torrGas constant (R) = 62.36 torr.L/mol KNumber of mole (n) = 0.024 moleVolume of gas (V) =?PV = nRT
729.93 × V = 0.024 × 62.36 × 296
Divide both sides by 729.93
V = (0.024 × 62.36 × 296) / 729.93
V = 0.61 L
Thus, the volume of the C₂H₂ gas collected is 0.61 L
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. A ring with a mass of 25.5 g appears to be pure silver. Rather than test for density, you can confirm the ring's composition by determining its specific heat. Suppose the ring is heated to a temperature of 84.0°C and then immersed in a container of water until the ring's temperature is 25.0°C. If the ring gives up 667.5 J of energy to the water, what is its specific heat? Is the ring made of silver (C = 0.234 J/g °C), nickel (C = 0.444 J/g. °C), or palladium (C = 0.244 J/g °C) help me
The specific heat capacity of the ring, given that the ring gives up 667.5 J of energy to the water is 0.444 J/gºC. The ring is made of nickel.
How do i determine the specific heat capacity of the ring?The specific heat capacity of the ring can be obtain as illustrated below:
Heat absorbed by water (Q) = 667.5 JHeat released by ring (Q) = -667.5 JMass of ring (M) = 25.5 gInitial temperature of ring (T₁) = 84.0 °CFinal temperature (T₂) = 25.0 °CChange in temperature (ΔT) = 25.0 - 84.0 = -59 °CSpecific heat capacity of ring (C) = ?Q = MCΔT
-667.5 = 25.5 × C × -59
-667.5 = -1504.5 × C
Divide both sides by -1504.5
C = -667.5 / -1504.5
C = 0.444 J/gºC
Thus, the specific heat capacity of the ring is 0.444 J/gºC. Hence, the ring is made of nickel
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Dimensional analysis with shapes
The surface area of the rectangular prism is 0.034 square meters.
For a rectangular prism with length l, width w, and height h, the surface area is:
Surface area = 2lw + 2lh + 2wh
Substituting the given values, we get:
Surface area = 2(10 cm x 5 cm) + 2(10 cm x 8 cm) + 2(5 cm x 8 cm)
Surface area = 100 cm² + 160 cm² + 80 cm² = 340 cm²
We can use dimensional analysis. So the conversion factor is:
1 m² / 10,000 cm²
Multiplying the surface area by this conversion factor, we get:
Surface area = 340 cm² x (1 m² / 10,000 cm²)
Surface area = 0.034 m²
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--The complete Question is, What is the surface area of a rectangular prism that has a length of 10 cm, a width of 5 cm, and a height of 8 cm? Use dimensional analysis to convert the answer to square meters--
What happens to a buffered solution when a small amount of base is added?
O The solution quickly becomes neutral.
O The solutions resists changes in pH.
O The solution slowly becomes acidic.
O The solution quickly becomes basic.
Answer:
solution resists changes in pH
Explanation:
the inherent property of buffers is to resist change to ph even when acids and bases are added. when the base is added, it is quickly neutralized by the conjugate acid, so the ph won't change.
Answer:
B: The solutions resists changes in pH.
Explanation:
Buffer reactions maintain stable pH of solutions.
What mass (grams) of sodium sulfate would be formed by the complete reaction of 137.3 grams of sodium hydroxide?
NaOH + H2SO4 --> Na2SO4 + HOH
The mass of sodium sulfate [tex](Na_2SO_4)[/tex] formed by the complete reaction of 137.3 grams of sodium hydroxide [tex](NaOH)[/tex] is 486.74 grams.
The balanced chemical equation for the reaction between sodium hydroxide [tex](NaOH)[/tex] and sulfuric acid [tex](H_2SO_4)[/tex] is:
[tex]NaOH[/tex] + [tex](H_2SO_4)[/tex] → [tex]Na_2SO_4[/tex] + [tex]2H_2O[/tex]
From the balanced equation, we can see that 1 mole of [tex]NaOH[/tex] reacts with 1 mole of [tex](H_2SO_4)[/tex] to produce 1 mole of [tex]Na_2SO_4[/tex] and 2 moles of water [tex](H_2O).[/tex]
The molar mass of [tex]NaOH[/tex] is 40.00 g/mol, which means that 137.3 grams of [tex]NaOH[/tex] is equal to 137.3 g / 40.00 g/mol = 3.4325 moles of [tex]NaOH[/tex].
Since 1 mole of [tex]NaOH[/tex] reacts with 1 mole of [tex](H_2SO_4)[/tex] to produce 1 mole of [tex](Na_2SO_4)[/tex] , we can say that 3.4325 moles of [tex]NaOH[/tex] will react with 3.4325 moles of [tex]H_2SO_4[/tex] to produce 3.4325 moles of [tex]Na_2SO_4[/tex].
The molar mass of [tex](Na_2SO_4)[/tex] is 142.04 g/mol, which means that 1 mole of [tex](Na_2SO_4)[/tex] has a mass of 142.04 g.
Therefore, 3.4325 moles of [tex](Na_2SO_4)[/tex] has a mass of 3.4325 moles x 142.04 g/mol = 486.74 grams.
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What is the minimum concentration of fluoride ions necessary to precipitate CaF2 from a 5.25 x 10-3 M solution of Ca(NO3)2? Ksp of CaF2 = 3.9 x 10-11
The minimum concentration of fluoride ions needed is 2.726 x 10⁻⁴ M.
How to solveTo find the minimum concentration of fluoride ions needed to precipitate CaF₂, we'll use the solubility product constant (Ksp) and the calcium ion concentration.
Ksp = [Ca²⁺][F⁻]²
Given: [Ca²⁺] = 5.25 x 10⁻³ M, Ksp = 3.9 x 10⁻¹¹
3.9 x 10⁻¹¹ = (5.25 x 10⁻³)[F⁻]²
Solve for [F⁻]:
[F⁻]² = (3.9 x 10⁻¹¹) / (5.25 x 10⁻³)
[F⁻]² = 7.4286 x 10⁻⁹
[F⁻] = 2.726 x 10⁻⁴ M
The minimum concentration of fluoride ions needed is 2.726 x 10⁻⁴ M.
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The iodine monobromide molecule, IBr, has a bond length of 249 pm and a dipole moment of 1.21 D. (a) Which atom of the molecule is expected to have a negative charge? (b) Calculate the effective charges on the I and Br atoms in IBr in units of the electronic charge, e.
a. Br will have the negative charge
b. The effective charges on the I and Br atoms are approximately +1.012e and -1.012e, respectively.
How to determine the negative chargea. To identify which atom within an IBr molecule will have a partial negative charge, we must consider each atom's electronegativity.
On the periodic table, iodine (I) has an electronegativity value of 2.66 while bromine (Br) boasts 2.96; since Br has higher electronegativity it will attract electrons more strongly and hence have an even stronger partial negative charge.
B. To calculate the effective charges on the I and Br atoms in IBr, we can use the dipole moment equation:
μ = Q * d
where μ is the dipole moment, Q is the effective charge, and d is the bond length.
We are given the dipole moment (μ) as 1.21 D, and the bond length (d) as 249 pm. However, we need to convert the units to the SI system before proceeding with the calculation.
[tex]1 D (Debye) = 3.336 * 10^-^3^0 cm,\\\\1 pm = 10^-^1^2 m.[/tex]
Now we can solve for the effective charge (Q):[tex]u = 1.21 D * (3.336 × 10^-^3^0 Cm/D)\\ \\= 4.03656 * 10^-^3^0 cm\\d = 249 pm * (10^-12 m/pm) = 2.49 * 10^-^1^0 m[/tex]
Q = μ / d
[tex]Q = (4.03656 * 10^-^3^0 cm) / (2.49 *10^-^1^0 m) \\\\\\=1.62151 * 10^-^2^0 C[/tex]
This effective charge represents the charge difference between the I and Br atoms. To express the charges in units of the elementary charge (e), we need to divide the effective charge by the elementary charge value (e = 1.602 × 10^-19 C):
Q_e =[tex]\frac{(1.62151 * 10^-^2^0 C)}{(1.602 * 10^-^1^9 C)} = 1.012[/tex]
The effective charges on the I and Br atoms are approximately +1.012e and -1.012e, respectively.
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Question 28
(1 mark)
Two other minerals can be seen in the photo:
galena, a dark grey mineral with the formula PbS
iron pyrite, a gold-coloured mineral with the formula FeS2
Compare their chemical formulas, by writing down one similarity and one difference between these two minerals.
Note: Pb = lead, Fe = iron, S = sulfur.
Question 29
(1 mark)
Wanting to create the beautiful golden colour of iron pyrite, FeS2, in the lab, a student mixes together black powdered iron (Fe) and yellow powdered sulfur (S). The result is a dull, yellowish grey powder. Propose why this attempt failed?
Question 30
(1 mark)
The student can vary the proportions of iron and sulfur by adding more of each powder to the mixture. Clarify why the same thing isn't true for the compound iron pyrite.
PbS, sometimes referred to as galena, is made up of lead (Pb) and sulfur (S) atoms and has a straightforward structure. Each lead atom forms a tetrahedral link with four sulfur atoms, while each sulfur atom forms a covalent bond with two lead atoms.
Each sulfur atom forms an octahedral link with six iron atoms, while each iron atom forms a covalent bond with two sulfur atoms. FeS2's crystal structure is a cubic, tightly packed lattice.
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As the hour of her new job approached, Emma could feel her excitement blank
As the hour of her new job approached, Emma could feel her excitement peak.
What word can replace intensify ?"Peak" is a synonym to "intensify" in this context because it means to reach the highest point or level of something. In the given passage, Emma's excitement is growing stronger and stronger as the time for her volunteer job approaches.
When her excitement "peaks," it means that it has reached the highest point of intensity, just like when something is intensified, it becomes stronger or more intense.
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If a balloon containing a mixture of gases where the partial pressure of oxygen is 12.8 psi, the partial pressure of hydrogen is 4.31 psi, and the partial pressure of nitrogen is 22.1 psi, then the actual pressure inside the balloon is…
Answer:
39.21 psi
Explanation:
According to Dalton's Law, the total pressure in the system is the sum of all the partial pressures, so all you need to do is add the partial pressures :)
add a given instant what is the rate of appearance at this time
The rate of appearance of NOBr at the given time is 9.80 × [tex]10^-^4[/tex] M/s which is the second option as the question asks to determine the rate of appearance of NOBr, which is a product of the given chemical reaction, at the given time when the rate of disappearance of Br₂ is known.
For every 1 mole of Br₂ that disappears, 2 moles of NOBr appear. Thus, we can set up a proportion:
(2 mol NOBr / 1 mol Br₂) = (rate of appearance of NOBr / rate of disappearance of Br₂)
Substituting the given values,
(2 mol NOBr / 1 mol Br₂) = (rate of appearance of NOBr / 4.90 x [tex]10^-^4[/tex] M/s)
Solving for the rate of appearance of NOBr,
rate of appearance of NOBr = (2 mol NOBr / 1 mol Br₂) x (4.90 x [tex]10^-^4[/tex] M/s) = 9.80 × [tex]10^-^4[/tex]M/s
The rate of appearance of NOBr at the given time is 9.80 × [tex]10^-^4[/tex] M/s.
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Haw many valance electrons in the following atoms.
O Na Sr
Answer:O has 6, Na has 1, and Sr has 2.
Explanation:
A compound has the formula X2Fe(CN)6 ∙ 12H2O, where X is an unknown element.
If the compound is 45.34% water by mass, what is the identity of element X?
The identity of element X in the compound X2Fe(CN)6 · 12H2O is sodium (Na).
To find the identity of element X in the compound X2Fe(CN)6 · 12H2O, we can start by determining the molar mass of the compound.
The molar mass of X2Fe(CN)6 is:
2 × molar mass of X + molar mass of Fe + 6 × molar mass of C + 6 × molar mass of N
= 2 × atomic mass of X + atomic mass of Fe + 6 × 12.01 g/mol + 6 × 14.01 g/mol
= 2 × atomic mass of X + 55.85 g/mol + 432.72 g/mol + 84.06 g/mol
= 2 × atomic mass of X + 572.63 g/mol
The molar mass of 12H2O is:
12 × (atomic mass of H + atomic mass of O) = 12 × (1.01 g/mol + 16.00 g/mol) = 216.24 g/mol
The total molar mass of the compound is:
2 × atomic mass of X + 572.63 g/mol + 216.24 g/mol = 2 × atomic mass of X + 788.87 g/mol
Now we can use the given information that the compound is 45.34% water by mass. This means that the mass of water in the compound is 45.34% of the total mass of the compound, and the mass of the rest of the compound (X2Fe(CN)6) is 100% - 45.34% = 54.66% of the total mass of the compound.
Let's assume we have 100 g of the compound. Then the mass of water in the compound is:
45.34 g water = 0.4534 × 100 g compound
The mass of the rest of the compound (X2Fe(CN)6) is:
54.66 g rest of the compound = 0.5466 × 100 g compound
We can now use the mass of the rest of the compound (X2Fe(CN)6) to find the number of moles of the compound:
moles of X2Fe(CN)6 = (54.66 g) / (2 × atomic mass of X + 572.63 g/mol)
We can also use the mass of water to find the number of moles of water:
moles of H2O = (45.34 g) / 18.02 g/mol
Since the compound has 12 moles of water per mole of X2Fe(CN)6, we have:
moles of X2Fe(CN)6 = 1/12 × moles of H2O
We can now set these two expressions for moles of the compound equal to each other and solve for the atomic mass of X:
(54.66 g) / (2 × atomic mass of X + 572.63 g/mol) = 1/12 × (45.34 g) / 18.02 g/mol
Simplifying this equation and solving for the atomic mass of X gives:
atomic mass of X = 22.99 g/mol
The atomic mass of X is very close to the atomic mass of sodium (22.99 g/mol), so it is likely that X is sodium. Therefore, the identity of element X in the compound X2Fe(CN)6 · 12H2O is sodium (Na).
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A 2.550×10−2 M glycerol solution (C3H8O3) in water is at 20.0 ∘C . The sample was created by dissolving a sample of C3H8O3 in water and then bringing the volume up to 1.000 L. It was determined that the volume of water needed to do this was 998.9 mL. The density of water at 20.0 ∘C is 0.9982 g/mL
a.) Calculate the molality of the glycerol solution
b.) Calculate the mole fraction of glycerol in this solution
c.) Calculate the concentration of the glycerol solution in percent by mass
d.) Calculate the concentration of the glycerol solution in parts per million by mass
The molality of the solution is 0.0256 m.
The mole fraction of glycerol is 0.00046
The percent by mass concentration of glycerol is 0.23%
The ppm concentration is 2300 ppm
What is the molality?Molality is a measure of the concentration of a solute in a solution. It is defined as the number of moles of solute per kilogram of solvent.
The formula for molality is:
molality = moles of solute / mass of solvent in kilograms
1) Density of water = mass/volume
Mass of water = Density * volume of water
Mass =[tex]0.9982 g/mL * 998.9 mL[/tex]
Mass =0.997 Kg of water
Number of moles of the glycerol = [tex]2.550* 10^-2 M * 1 L[/tex]
= [tex]2.550*10^-2[/tex] moles
Molality of the solution = [tex]2.550*10^-2[/tex] moles/0.997 Kg
= 0.0256 m
Number of moles of water = 998.9/18 g/mol
= 55.5 mole
Mole fraction of glycerol = [tex]2.550*10^-2[/tex] /[tex]2.550*10^-2[/tex] + 55.5
= 0.00046
By percent by mass;
2.3/1001.2 * 100/1
= 0.23%
Mass of glycerol = 2.3 g
Volume of solution = 1 L
Thus we have concentration in ppm as;
[tex]2.3 * 10^3[/tex] mg/ 1 L =2300 ppm
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If the reaction A (aq) + B (aq) C(aq) has a Ka value equal to 4.26 x 10-6, what is the G value at 25 °C if the concentrations are as follows:
[A] = 1.50 M
[B] = 1.00 M
[C] = 5.00 x 10-5 M
The Gibbs free energy change for the given reaction at 25°C and the given concentrations is -25.5 kJ/mol
The Gibbs free energy change (∆G) of a reaction can be calculated using the equation:
∆G = -RT ln(K)
Where R is the gas constant (8.314 J/molK), T is the temperature in Kelvin, and K is the equilibrium constant.
The equilibrium constant (K) can be calculated from the acid dissociation constant (Ka) as:
K = [C] ÷ ([A] × [B])
Substituting the given values, we get:
K = (5.00 x 10⁻⁵) ÷ (1.50 x 1.00) = 3.33 x 10⁻⁵
Therefore,
∆G = - (8.314 J/molK) × (298 K) × ln(3.33 x 10⁻⁵)
= 25.5 kJ/mol
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* For all 3 trials find the moles of KHC8H4O4 using the grams of KHC8H4O4. Show all work!
* Use the mole ratio from question 1 to find the moles of NaOH used. Remember, in a 1:1 ratio if we use 1 mole of KHC8H4O4, then we use 1 mole of NaOH. Record the moles of NaOH used in each trial below.
Trial 1 ________________
Trial 2 ________________
Trial 3 ________________
At equivalence point, the reaction is seen to consume approximately 0.0024973 moles of KHP and then 0.0024973 moles of NaOH
How to calculate the mole ratio?The primary aim in this problem is to standardize a solution of the sodium hydroxide, NaOH, with the aid of potassium hydrogen phthalate, KHP.
The beginning point in this problem is the balanced chemical equation with respect to this neutralization reaction
KHP (aq] + NaOH(aq] → KNaP(aq] + H₂O(l]
The important thing that we are going to observe is that there is a ratio of 1:1 mole ratio between the two reactants. This suggests to us that the equivalence point can be attained by getting equal number of moles of KHP and of NaOH to react with each other.
We will begin with 0.5100 g of KHP. To obtain the molar amount of acid utilized for the experiment, we will make use of its molar mass of 0.5100g⋅
molar mass of KHP
1 mole KHP 204.22g = 0.0024973 moles KHP
Thus, at equivalence point, the reaction is seen to consume approximately 0.0024973 moles of KHP and then 0.0024973 moles of NaOH, due to the fact that it's what the 1:1 mole ratio suggests to us.
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Calculate the energy difference (deltaE, in Joules) of an electron's transition from n = 6 to n = 1 in a hydrogen atom.
The energy difference of an electron's transition from n = 6 to n = 1 in a hydrogen atom is approximately -2.17 × 10⁻¹⁸ Joules.
To calculate the energy difference (deltaE) of an electron's transition from n = 6 to n = 1 in a hydrogen atom, we can use the following equation:
deltaE = -13.6 * (1/n_final^2 - 1/n_initial^2) eV
where n_initial is the initial energy level (6 in this case), n_final is the final energy level (1 in this case), and -13.6 eV is the ionization energy of hydrogen.
Converting eV to Joules, we get:
1 eV = 1.602 x 10^-19 J
Therefore, deltaE in Joules can be calculated as follows:
deltaE = -13.6 * (1/1^2 - 1/6^2) * 1.602 x 10^-19 J/eV
deltaE = -2.179 x 10^-18 J
Therefore, the energy difference (deltaE) of an electron's transition from n = 6 to n = 1 in a hydrogen atom is -2.179 x 10^-18 J.
To calculate the energy difference (ΔE) for an electron's transition from n = 6 to n = 1 in a hydrogen atom, you can use the following formula:
ΔE = -13.6 eV * (1/nf² - 1/ni²)
Where ΔE is the energy difference in electron volts (eV), nf is the final energy level (1 in this case), and ni is the initial energy level (6 in this case).
ΔE = -13.6 eV * (1/1² - 1/6²)
ΔE ≈ -13.56 eV
Now convert electron volts to Joules:
1 eV = 1.6 × 10⁻¹⁹ J
ΔE ≈ -13.56 eV * 1.6 × 10⁻¹⁹ J/eV
ΔE ≈ -2.17 × 10⁻¹⁸ J
So, approximately -2.17 × 10⁻¹⁸ Joules is the energy difference of an electron's transition from n = 6 to n = 1 in a hydrogen atom.
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