The pH of the buffer after the addition of 0.020 mol of NaOH is 4.83.
Henderson-Hasselbalch equation: pH = pKa + log([A^-]/[HA]),
[CH3COOH] = 0.300 mol/1.00 L = 0.300 M
[CH3COO^-] = 0.300 mol/1.00 L = 0.300 M
CH3COOH + NaOH → CH3COO^- + H2O
[CH3COOH] = (0.300 mol - 0.020 mol)/1.00 L = 0.280 M
CH3COO^-] = (0.300 mol + 0.020 mol)/1.00 L = 0.320 M
pH = pKa + log([CH3COO^-]/[CH3COOH])
pH = 4.74 + log(0.320/0.280)
pH = 4.83
The pH of a solution can be measured using a pH meter or pH paper, which changes color based on the pH of the solution. It is a dimensionless quantity that indicates the concentration of hydrogen ions (H+) in a solution. pH stands for "power of hydrogen" and is defined as the negative logarithm of the hydrogen ion concentration. A pH of 7 is considered neutral, pH values below 7 indicate acidity, and pH values above 7 indicate alkalinity.
pH is an important parameter in many chemical and biological processes, as it can affect the behavior and properties of molecules and ions in solution. Maintaining the correct pH in biological systems is critical for many physiological processes, and pH control is important in many industrial processes as well.
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Light can bounce off objects. This is called reflection, and it's what allows us to see objects. This drawing shows a light ray reflecting from the blue construction paper. Although many light waves are hitting the paper and reflecting from it, showing just one ray helps us follow the path of a single wave. white light from flashlight blue light ray seen For each color of paper, which part of white light is reflected?
For each color of paper, the part of white light that is reflected depends on the color of the paper. When white light strikes an object, some of the light is absorbed by the object, some of it is transmitted through the object, and some of it is reflected.
The color of the object that we see is the color of the light that is reflected by the object.
For example, when white light strikes blue paper, the blue color of the paper absorbs all the other colors of the spectrum except blue, which is reflected back to our eyes. This is why we see the paper as blue. Similarly, when white light strikes red paper, the red color of the paper absorbs all the other colors except red, which is reflected back to our eyes. This is why we see the paper as red.
In summary, the color of an object is determined by the color of the light that is reflected by the object, and the color of the light that is reflected depends on the color of the object and the colors of the spectrum that are absorbed or transmitted by the object.
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Which gas is a greenhouse gas?
Oxygen
ammonia
Nitrogen gas
Water vapor
Answer:Nitrogen gas
Explanation:
I believe it is nitrogen correct me if i am wrong.
In a weather forecast on a Seattle radio station the barometric pressure was reported to be 29.4 inches. What is the pressure in SI units? (1 inch = 25.4 mm, 1 atm = 760 mmHg)
Answer:
99585.48 Pa or approximately 0.981 atm.
Explanation:
To convert the barometric pressure from inches to SI units (Pascals), we can use the following conversions:
1 inch = 25.4 mm
1 mm = 0.1 cm
1 cm = 10 mm
1 mmHg = 133.322 Pa
1 atm = 760 mmHg
Therefore, we can calculate the pressure in SI units as follows:
Convert inches to mm: 29.4 inches x 25.4 mm/inch = 746.76 mm
Convert mmHg to Pa: 746.76 mm x 133.322 Pa/mmHg = 99585.48 Pa
Convert atm to Pa: 1 atm x 760 mmHg/atm x 133.322 Pa/mmHg = 101325 Pa
Calculate the pressure in SI units: 99585.48 Pa/101325 Pa/atm = 0.981 atm
Therefore, the barometric pressure in SI units is 99585.48 Pa or approximately 0.981 atm.
determine the mole fraction of each component in a solution in which 3.57 g of sodium chloride (NaCI) is dissolved in 25.0 g of water. Show the steps of the calculation.
The mole fractions of water and sodium chloride in the solution are 0.9578 and 0.0422, respectively.
What is the NaCl mole fraction?If 0.010 moles of sodium chloride dissolve in 100 grammes of purified water, the mole fraction of sodium chloride and water. Water has a mole fraction of 0.982 and NaCl has a mole fraction of 0.018.
1: Determine the sodium chloride moles (NaCl)
NaCl has a molar mass of 58.44 g/mol. As a result, 3.57 g of NaCl has the following number of moles in it:
moles of NaCl = mass of NaCl / molar mass of NaCl
moles of NaCl = 3.57 g / 58.44 g/mol
moles of NaCl = 0.0612 mol
2: Determine the water moles (H2O)
Water has a molar mass of 18.02 g/mol. As a result, 25.0 g of water contains the following number of moles of water:
moles of H2O = mass of H2O / molar mass of H2O
moles of H2O = 25.0 g / 18.02 g/mol
moles of H2O = 1.388 mol
3: Determine the total moles of the solution.
The moles of NaCl and water together make up the total amount of moles in the solution.
total moles = moles of NaCl + moles of H2O
total moles = 0.0612 mol + 1.388 mol
total moles = 1.4492 mol
4: Determine the mole fraction for each element.
NaCl's mole fraction is:
mole fraction of NaCl = moles of NaCl / total moles
mole fraction of NaCl = 0.0612 mol / 1.4492 mol
mole fraction of NaCl = 0.0422
Water's mole fraction is:
mole fraction of H2O = moles of H2O / total moles
mole fraction of H2O = 1.388 mol / 1.4492 mol
mole fraction of H2O = 0.9578
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If you mastered this assignment, you will do exactly as it says to do.
What’s the Count?
NaC2HO4
Elements found in Formula:
Number of atoms in Element:
H2F5BLi
Elements found in Formula:
Number of atoms in Element:
2He2PSO4
Elements found in Formula:
Number of atoms in Element:
3He2O4PH
Elements found in Formula:
Number of atoms in Element:
The elements are the simplest chemical forms and they cannot be broken down through chemical reactions. There are many elements in the given formulas.
What are elements?
The elements are defined as those substances whose atoms all have the same number of protons. The elements are considered as the building blocks of matter. Each element has an atomic number and a symbol.
Each atom is regarded as an element. The elements create bonds to form molecules. The isotopes are the elements with the same atomic number but different mass numbers.
NaC₂HO₄ - 'N' , 'C', 'H','O'
H₂F₅BLi - 'H','F','B','Li'
He₂PSO₄ - 'He', 'P','S','O'
He₂O₄PH - 'He', 'O','P','H'
Fluoride, a very stable form of fluorine, is often added to toothpaste and drinking water to prevent
tooth decay. What is the formula of this species?
a. F
b. Fl-
C. Fl+
d. F²-
Answer:
B
Explanation:
The Fluoride ion is a part of the diatomic molecule [tex]F_{2}[/tex] which has two [tex]F^{-}[/tex] molecules that are paired together and share electrons in order to gain a full octet of electrons, which is why [tex]F_{2}[/tex] is the most stable form of fluorine and why it is the way natural fluorine is found. Fluoride refers to half of this diatomic molecule which is [tex]F^{-}[/tex].
Note: Diatomic simply means a molecule that contains two atoms.
Nuclear reactions
A. Involve electrons
B. Can form compounds
C. Can form different elements
D. Depend on chemical combination
Answer: C
Explanation:
Nuclear reactions involve a change in an atom's nucleus, usually producing a different element. Chemical reactions, on the other hand, involve only a rearrangement of electrons and do not involve changes in the nuclei.
How many moles of CaC2 are needed to react with 49.0 grams H2O
In order to react with 45 g of water 1.25 moles of CaC₂ are required. Explanation: Given data: Moles of CaC₂ needed = ? Mass of water = 45.0 g.
[tex] \: [/tex]
1. Billy Beaker is reacting 7.98 mL of 2.50 M HCl with excess NaOH. How many grams of water will be produced by this neutralization reaction?
2. Emily Erlenmeyer is reacting 2.43 mL of 2.50 M H2SO4 with 2.51 mL of 3.00 M NaOH. How many grams of water will be produced by this neutralization reaction?
Use molarity and stoichiometry
1. The amount of water produced by the reaction is 0.359 g.
2. The amount of water produced by the reaction is 0.219 g.
How do you calculate the number of moles neutralized in a titration?To calculate the number of moles of acid neutralized by the tablet, subtract the number of moles of acid neutralized in the titration from the initial solution's moles of acid. Understand and explain standardization in the context of acidic and basic solutions used as reagents in experiments.
1. The neutralization reaction,
HCl (aq) + NaOH (aq) → NaCl (aq) + H2O (l)
we have to calculate the number of moles of HCl that react,
moles of HCl = volume of HCl x concentration of HCl
= 7.98 mL x 2.50 mol/L / 1000 mL/L
= 0.01995 mol
Since NaOH is in excess,
As a result, the amount of water produced will be equal to the amount of HCl that reacts:
moles of water = moles of HCl = 0.01995 mol
we can use the molar mass of water (18.015 g/mol)
mass of water = moles of water x molar mass of water
= 0.01995 mol x 18.015 g/mol
= 0.359 g
2. The neutralization reaction between H2SO4 and NaOH is:
H2SO4 (aq) + 2 NaOH (aq) → Na2SO4 (aq) + 2 H2O (l)
we have to calculate the number of moles of H2SO4 that react,
moles of H2SO4 = volume of H2SO4 x concentration of H2SO4
= 2.43 mL x 2.50 mol/L / 1000 mL/L
= 0.00608 mol
Now, we have to calculate the number of moles of NaOH that react:
moles of NaOH = volume of NaOH x concentration of NaOH
= 2.51 mL x 3.00 mol/L / 1000 mL/L
= 0.00753 mol
we need to use the stoichiometry of the balanced equation,
moles of water = moles of H2SO4 x (2 moles of water / 1 mole of H2SO4)
= 0.00608 mol x 2
= 0.01216 mol
we can use the molar mass of water (18.015 g/mol)
mass of water = moles of water x molar mass of water
= 0.01216 mol x 18.015 g/mol
= 0.219 g
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How many hydrogen donors does the following molecule have?
For the compound Rbl what are the formulas of all the species you expect to be present in aqueous solution? If there are significant differences in the amounts of species present, use the designations major and minor to distinguish those species present in greater amounts (major species) from those present in lesser amounts (minor species). A. Major species: Rb∗: Minor species: 1 :
B. Major species: I. Minor species: Rb∗: C. Major species: Rb∗ and K, Minor species: NA. D. Major species: NA. Minor species: Rb∗ and I.
The compound RbI is a salt that dissociates in an aqueous solution, producing Rb+ and I- ions.
Major species: Rb+, Minor species: I-Major species: I-, Minor species: Rb+Major species: Rb+ and I-, Minor species: none (since K is not part of the compound)Major species: H2O and I-, Minor species: Rb+ (since RbI is not very soluble, and therefore only a small amount of Rb+ ions will be present in solution)An aqueous solution is a mixture of a substance in water, where the water is the solvent. Water is a versatile solvent, which can dissolve a wide range of compounds due to its polar nature. The concentration of a solute in an aqueous solution is usually expressed in terms of molarity or molality, which indicate the number of moles of solute per liter or kilogram of solvent, respectively.
In an aqueous solution, water molecules surround the dissolved solute particles and separate them from one another. This process is called hydration. When a substance dissolves in water, it can undergo a chemical change, such as ionization or hydrolysis, that affects its properties. Aqueous solutions play a critical role in many chemical reactions and biological processes. The pH of an aqueous solution, which measures the acidity or basicity, is also an essential property that affects its chemical behavior.
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Ba(NO3)2(aq)+CuSO4(aq) complete and balance the precipitation reaction.
Explained answer:
Ba(NO3)2(aq) + CuSO4(aq) -> BaSO4(s) + Cu(NO3)2(aq)
This is a precipitation reaction where barium nitrate and copper sulfate react to form barium sulfate , which is insoluble in water and therefore precipitates out of solution, and copper nitrate.
To balance the equation, we need to ensure that the number of atoms of each element is the same on both sides of the equation. First, we balance the sulfate ions:
Ba(NO3)2(aq) + CuSO4(aq) -> BaSO4(s) + Cu(NO3)2(aq)
Next, we balance the barium and copper ions:
Ba(NO3)2(aq) + CuSO4(aq) -> BaSO4(s) + Cu(NO3)2(aq)
Finally, we balance the nitrate ions:
Ba(NO3)2(aq) + CuSO4(aq) -> BaSO4(s) + 2Cu(NO3)2(aq)
Therefore, the balanced precipitation reaction is: Ba(NO3)2(aq) + CuSO4(aq) -> BaSO4(s) + 2Cu(NO3)2(aq).
What quantity in moles of precipitate are formed when 52.9 mL of 0.400 M Ca(NO₃)₂ is mixed with excess K₃PO₄ in the following chemical reaction?
3 Ca(NO₃)₂(aq) + 2 K₃PO₄(aq) → Ca₃(PO₄)₂(s) + 6 KNO₃(aq)
Answer:
To determine the number of moles of precipitate formed in the reaction, we first need to find the limiting reagent.
From the balanced chemical equation, we know that 3 moles of Ca(NO₃)₂ react with 2 moles of K₃PO₄ to produce 1 mole of Ca₃(PO₄)₂.
Let's first calculate the number of moles of Ca(NO₃)₂ present in 52.9 mL of 0.400 M solution:
moles of Ca(NO₃)₂ = concentration × volume
= 0.400 mol/L × 0.0529 L
= 0.02116 mol
Since the stoichiometric ratio of Ca(NO₃)₂ to K₃PO₄ is 3:2, we would need 3/2 times the number of moles of K₃PO₄ to react completely with the given amount of Ca(NO₃)₂. However, the problem states that we have an excess of K₃PO₄, which means that all of the Ca(NO₃)₂ will react with the available K₃PO₄.
Therefore, the number of moles of Ca₃(PO₄)₂ that will be formed is equal to the number of moles of Ca(NO₃)₂ used in the reaction, which is 0.02116 mol.
Hence, 0.02116 moles of Ca₃(PO₄)₂ precipitate will be formed when 52.9 mL of 0.400 M Ca(NO₃)₂ is mixed with excess K₃PO₄ in the given chemical reaction.
How many different mRNA sequences could encode the amino acid sequence Met–Leu–Val–His?
Answer:
Therefore, the number of potential sequences is the product of the number of different potential codons for this tripeptide, which gives us a total of (1 × 6 × 6 × 3) = 108 different mRNA sequences that can code for the tripeptide Met-Leu-Arg.
What happens to the potential energy of the molecules in a reaction? A. The reactants only lose potential energy when forming products. B. The potential energy of the products is equal to that of the reactants. C. The potential energy of the molecules does not change in a reaction. D. The potential energy of the molecules changes during a reaction.
Potential energy is changed into kinetic energy throughout this process, which is the heat produced during reactions. On the contrary, this happens in an endothermic process.
What happens to the molecules' potential energy during a reaction?Bonds break, new bonds form, and protons and electrons move from a structure with greater potential energy to one with lower potential energy during an exothermic reaction. Potential energy is changed into kinetic energy throughout this process.
What is a reaction's potential energy?The energy that is held inside the bonds and phases of the reactants and products is measured by potential energy. The internal energy includes this potential energy. The internal energy of chemical reactions, also known as enthalpy, stands in for the system's total energy.
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If you measured the absorbance of the copper solution using a wavelength of 610 nanometers during a copper/silver electrolytic cell experiment, would you expect the absorbance to go up, down or stay the same as the reaction proceeds? Justify why
Several sizes of Cu particles' optical absorption spectra are also described; these spectra contain the plasmon band in the 560–580 nm range and a UV band at 222 nm, becoming flatter with increasing particle size.
What wavelength did you employ to gauge the solutions' absorbance of copper II sulphate?From the calibration figure, calculate the copper (II) sulphate concentrations in your two unknown samples. Useful wavelength is 700 nm.
How can you figure out the copper II sulphate solution's concentration?By testing an unknown CuSO4 solution's absorbance with a Colorimeter, you can ascertain its concentration. The corresponding concentration can be obtained on the horizontal axis of the graph by placing the absorbance of the unknown on the vertical axis.
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If you mastered this assignment, you will do exactly as it states
1. Do you think a chemical reaction took place in Part 1 when you added the galvanized nail to the acid and water, and in Part 2 when the yeast was added to the hydrogen peroxide? Explain your answer
2. Did the same result occur in both parts when you held up a lighted splint to the jar’s mouth?
What can you conclude from this about the identity of the gas(es) in Parts 1 and 2?
3. In both parts of the activity, you conducted a second trial without having to remix the chemicals. How was this possible?
4. In 1937, a large passenger airship called the Hindenburg mysteriously caught fire. Because
the airship was filled with hydrogen gas, it immediately exploded once the fire reached the gas.
Given this information, do you think one of the reactions above may have produced hydrogen?
Use your data to explain your answer.
Conclusions
Keeping the goal in mind, write a one- or two-sentence conclusion that summarizes the results of
this activity and how they met the established goal.
Answer:
1: Yes I do believe it was a chemical reaction because gas and bubbles were created which can only happen during a chemical reaction also temperature change is another reason for a chemical change.
2: No on the second try I heard fizzing and type of popping concluding that its oxygen gas that was formed from the mixture since oxygen gas could re ignite the flame.
3: The trials all used gasses so there is no need to remix when its still creating gas and keeping the lid on keeps the gas in.
4: Yes the muriatic acid when mixed with the water and galvanised nail form hydrogen gas the popping and fizzing are indictors that it is indeed hydrogen
Explanation:
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which of the following substance is a non electrolytes ?
(a)H2SO4
(b)CH3COOH
(c)C6H12O6
(d)NH4Cl
Answer:
C
Explanation:
Glucose (sugar) readily dissolves in water, but because it does not dissociate into ions in solution, it is considered a nonelectrolyte; solutions containing glucose do not, therefore, conduct electricity.
Work out what the substances are and which one was used? I know what the first one is and I know what other chromatography one is used i just don't know how to identify it.
d (i) Rf of 0.54 could be substance B or substance D.
d (ii) It would eliminate any potential errors or uncertainties from the first experiment.
Describe Chromatography?Chromatography is a laboratory technique used for separating and analyzing mixtures of substances. It involves passing a mixture through a stationary phase, which is typically a solid or liquid, and a mobile phase, which is a gas or liquid. The different components of the mixture will interact differently with the stationary and mobile phases, causing them to move at different rates and ultimately separate from each other.
1 (d) (i) Based on the Rf values given in the table, two possible identities for the substance that caused the spot with an Rf of 0.54 could be substance B or substance D.
1 (d) (ii) To confirm which one of the substances (B or D) caused the spot, a chromatography experiment with a different solvent could be carried out. This would involve using a solvent that has a different polarity than water, such as hexane or chloroform, and running a new paper chromatography of the mixture. If the same spot appears at the same Rf value as in the previous experiment, then it is likely that the substance causing the spot is substance B. However, if a different spot appears at a different Rf value, then the substance causing the original spot is likely to be substance D. This experiment would help to confirm the identity of the substance causing the spot and would eliminate any potential errors or uncertainties from the first experiment.
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Write the equilibrium constant expression, K, for the following reaction: If either the numerator or denominator is blank,
please enter 1.)
N 2 (g)+3H 2 (g) 2NH 3 (g)
The molar concentrations of nitrogen gas, hydrogen gas, and ammonia gas at equilibrium are [N2], [H2], and [NH3], respectively. The equilibrium constant expression, K, for the above reaction is K = [NH3]2 / ([N2] * [H2]3).
How much is K's equilibrium constant?Equilibrium constant (K) is a mathematical ratio that displays the product concentrations subtracted from the reactant concentrations.
What is the expression for the K equilibrium?The expression for the equilibrium constant is expressed as. K=adD·aeEabB·acC. The number of moles of each substance is represented by the lower case letters in the balanced equation, while the substance itself is represented by the upper case letters. Equilibrium favours products if K>1. Equilibrium favours the reactants if K 1.
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4.8g of salt(z) dissolved in 250cm³ of distilled water give a concentration of 0.80m/dm³. Calculate the molar mass of the salt(z)
Answer:
24 g/mol.
Explanation:
To calculate the molar mass of the salt (z), we need to use the formula:
concentration = number of moles / volume of solution
We know that the concentration is 0.80 mol/dm^3, and the volume of the solution is 250 cm^3, which is equivalent to 0.25 dm^3. Therefore, we can rearrange the formula to solve for the number of moles of salt (z):
number of moles = concentration x volume of solution
number of moles = 0.80 mol/dm^3 x 0.25 dm^3
number of moles = 0.20 mol
Next, we can calculate the mass of salt (z) in the solution using the formula:
mass = number of moles x molar mass
We know that the mass of salt (z) is 4.8 g, and we just calculated that the number of moles is 0.20 mol. Therefore, we can rearrange the formula to solve for the molar mass:
molar mass = mass / number of moles
molar mass = 4.8 g / 0.20 mol
molar mass = 24 g/mol
Therefore, the molar mass of the salt (z) is 24 g/mol.
Answer:24 g/mo
Explanation:
What allows a person to interact with web browser software?
O user interface
O file transfer protocol
O networking
O URLS
The ability to interact with web browser software is provided by the user interface. It offers a visual user interface that enables entry of commands and response from the programme.
What makes it possible for a user to engage with the web pages?Via a Web browser, a user can interact with data or software running on a remote server using a Web user interface or Web app. The user interacts with the content on a web browser, which functions as a client, after downloading it from the web server.
What is a piece of software that enables user interaction with websites?A web browser is a piece of software that enables a user to view and interact with content that may be found on a website, including text, photos, videos, music, and other types of media. Hyperlinks to other web pages at the same or different websites can be found in the text and images on a web page.
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In a common medical laboratory determination of the concentration of free chloride ion
in blood serum, a 'serum sample is titrated with a Hg(NO3)2 solution.
2Cl(aq) +Hg(NO3)2(aq) → 2NO3(aq) + HgCl₂(s)
What is the C1 concentration in a 0.25-mL sample of normal serum that requires 1.46
mL of 8.25 × 10-4 M Hg(NO3)2 (aq) to reach the end point?
The concentration of Cl- in the serum sample is 4.82 x 10-3 M.
What is concentration?Concentration is a mental state in which a person focuses on a single activity or thought. It involves the ability to focus one’s attention on a task, block out distractions, and maintain focus for an extended period of time. Concentration is an important skill for productivity, problem-solving, and creativity. It is also essential for academic success, as students must be able to focus on their studies for long periods of time. Concentration can also be useful in everyday life, as it helps us to make decisions, think clearly, and stay organized.
The principle of the titration is based on the following equation:
2Cl(aq) +Hg(NO3)2(aq) → 2NO3(aq) + HgCl₂(s)
Given the data, we can calculate the concentration of Cl- in the serum sample:
1. Calculate the moles of Hg(NO3)2 (aq) used in the titration:
Moles = (concentration of Hg(NO3)2) x (volume of Hg(NO3)2)
= (8.25 x 10-4 M) x (1.46 mL)
= 0.001205 mol
2. Calculate the moles of Cl- in the sample:
Moles = (concentration of Cl-) x (volume of Cl-)
= (C1) x (0.25 mL)
= 0.001205 mol
3. Calculate the concentration of Cl- in the serum sample:
Concentration of Cl- = (moles of Cl-) / (volume of serum sample)
= 0.001205 / 0.25 mL
= 4.82 x 10-3 M
Therefore, the concentration of Cl- in the serum sample is 4.82 x 10-3 M.
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PLEASE HELP ASAP LAB QUESTIONS
Experiment 1 Procedure:
1. Measure 50.0 mL of water (tap) into a 100 mL graduated cylinder and pour it into a large coffee cup.
2. Determine the temperature of this water
3. Measure out 2.00 g of sodium hydroxide into a piece of paper towel *tare scale!
4. Add the sodium hydroxide to the water in the coffee cup and put a small cup over it, with the thermometer through the hole. Stir GENTLY with the thermometer and record the temperature every 30 seconds for 3 minutes or until it peaks. Record this in a properly labelled table.
5. Let this stand for 45 minutes before proceeding to Exp. 2.
sodium hydroxide and water lab
PURPOSE OF EXPERIMENT: To find Heat of Solution of sodium hydroxide and to find the heat of neutralization between sodium hydroxide and hydrochloric acid.
EXPERIMENT 1 WHAT WE FOUND:
WHAT WE FOUND IN EXP 1:
T (temp.) initial = 20 degrees C
T (temp) FINAL = 28.5 degrees C
moles of sodium hydroxide = 0.0518mol
the molar mass of sodium hydroxide = 39.969g/mol
C (specific heat of water) = 4.184J/g degrees C
THE NUMBER OF TRIALS FOR TEMP IN EXP 1
1st trial = 21 C
2nd trial = 24.5 C
3rd trial = 26 C
4th trial = 26 C
5th trial = 28 C
6th trial = 28.5 C
7th trial = 28.5 C (final temp)
ANALYSIS FOR EXPERIMENT ONE:
1. Determine the moles of sodium hydroxide (NaOH) from the experiment.
2. Determine Qsurroundings and Qrxn
3. Determine the enthalpy for the dissociation of sodium hydroxide (delta H sol)
4. Write the thermochemical equation for the dissociation of sodium hydroxide TWO ways and write an enthalpy diagram
5. What assumptions did you make to calculate #2? (some example assumptions to make: assume that the solution is water and that heat and density COULD be the same as water, etc)
6. Research the actual value and determine the percent error
7. In terms of bonds breaking and forming, what is RESPONSIBLE FOR ENTHALPY CHANGE?
Answer:
Explanation:
The moles of sodium hydroxide (NaOH) from the experiment is 0.0518 mol.
Qsurroundings = -Qrxn, so Qsurroundings = -(m x C x ΔT) = - (50.0 g x 4.184 J/g°C x (28.5°C - 20.0°C)) = - 3464.96 J; Qrxn = -Qsurroundings = 3464.96 J
ΔHsol = Qrxn / moles of NaOH = 3464.96 J / 0.0518 mol = -66,871.12 J/mol or -66.87 kJ/mol
The thermochemical equation for the dissociation of sodium hydroxide:
2NaOH(s) → 2Na+(aq) + 2OH-(aq) + heat
or
NaOH(s) → Na+(aq) + OH-(aq) + heat
The enthalpy diagram shows an energy input (endothermic) for the dissociation of NaOH.
Some assumptions made to calculate #2 include assuming the specific heat capacity of water is the same as the specific heat capacity of the NaOH solution and that the density of the solution is the same as water.
The actual value of ΔHsol for NaOH is -44.51 kJ/mol, so the percent error is:
|(-44.51 kJ/mol - (-66.87 kJ/mol)) / -44.51 kJ/mol| x 100% = 50.21%
The breaking and forming of chemical bonds are responsible for the enthalpy change. In the case of the dissociation of NaOH, the bond between the Na and OH groups is broken, which requires an input of energy, making the process endothermic.
From the experiment, the moles of sodium hydroxide (NaOH) is found to be 0.0518 mol.
What is Moles?
In chemistry, a mole is a unit used to measure the amount of a substance, typically atoms or molecules. One mole of a substance is defined as the amount of that substance which contains the same number of particles (atoms, molecules, or ions) as there are in exactly 12 grams of carbon-12
In the experiment described, 2.00 grams of sodium hydroxide (NaOH) was added to 50.0 mL of water in a coffee cup. The temperature of the water was measured before adding the NaOH and recorded as the initial temperature (T initial). The NaOH was then added to the water and the mixture was stirred gently with a thermometer, while the temperature was recorded every 30 seconds for 3 minutes or until it peaked. The highest temperature reached during this time was recorded as the final temperature (T final).
Using the formula Q = mCΔT, where Q is the amount of heat transferred, m is the mass of the water, C is the specific heat of water, and ΔT is the change in temperature, the amount of heat released or absorbed by the NaOH and water mixture can be calculated.
Since the reaction between NaOH and water is an exothermic reaction, the heat released by the reaction is equal to the heat absorbed by the water.
From the moles of NaOH added and its molar mass, the mass of NaOH can be calculated.
Then, the heat of solution can be calculated using the formula:
Heat of solution = Q / moles of NaOH
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How many grams of butanethiol can be deodorized by reaction with 4.50 mL of 9.70×10−2 M NaOCl
The mass of butanethiol that can be deodorized by reaction with 4.50 mL of [tex]9.70*10^{-2[/tex] M [tex]NaOCl[/tex] is 46.356g.
Given the volume of butanethiol = 4.50mL
The concentration of [tex]NaOCl[/tex] = [tex]9.70 * 10^{-2[/tex]M
The mass of butanethiol that can be deodorized = m
Butanethiol ([tex]C4H10S[/tex]) has a molar mass of 106.2 g/mol.
Therefore, the amount of butanethiol that can be deodorized by reaction with 4.50 mL of [tex]9.70 * 10^{-2} M[/tex] [tex]NaOCl[/tex] is calculated as follows:
molarity is calculated as number of moles/volume such that:
Moles of [tex]NaOCl[/tex] =[tex](4.50 mL) * (9.70 * 10^{-2} M) = 0.4365 mol[/tex]
We know that mass of substance = moles*molar mass of substance
mass of butanethiol = (0.4365 mol [tex]C4H10S[/tex])*(106.2 g/mol [tex]C4H10S[/tex]) = 46.356 g [tex]C4H10S[/tex]
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2 HC₂H₂O₂ + Ba(OH)₂
Ba(C₂H₂O₂)₂
+ 2 H₂O
A sample of barium hydroxide (Ba(OH)₂) 0.67 M is titrated with acetic acid (HC₂H₂O₂) 1.2 M. If 55.00 mL of acetic
acid were required, what was the volume of the sample of barium hydroxide?
153.54 mL Ba(OH)₂
(magenta)
98.51 mL Ba(OH)2
(red)
49.25 mL Ba(OH)₂
(blue)
The balanced chemical equation for the reaction between acetic acid and barium hydroxide is:
2 HC₂H₂O₂ + Ba(OH)₂ → Ba(C₂H₂O₂)₂ + 2 H₂O
From the balanced equation, we can see that 2 moles of acetic acid react with 1 mole of barium hydroxide to produce 1 mole of barium acetate and 2 moles of water.
The number of moles of acetic acid used in the titration can be calculated as follows:
moles of HC₂H₂O₂ = Molarity × volume in liters
moles of HC₂H₂O₂ = 1.2 M × (55.00 mL / 1000 mL/ L)
moles of HC₂H₂O₂ = 0.066 moles
From the balanced equation, we know that 2 moles of acetic acid react with 1 mole of barium hydroxide. Therefore, the number of moles of barium hydroxide present in the titration can be calculated as:
moles of Ba(OH)₂ = 0.066 moles / 2
moles of Ba(OH)₂ = 0.033 moles
The molarity of the barium hydroxide solution can be calculated as:
Molarity = moles / volume in liters
We rearrange this equation to solve for the volume:
volume in liters = moles / Molarity
volume in liters = 0.033 moles / 0.67 M
volume in liters = 0.04925 L
Finally, we convert the volume to milliliters:
volume in mL = 0.04925 L × 1000 mL/L
volume in mL = 49.25 mL
Therefore, the volume of the sample of barium hydroxide used in the titration is 49.25 mL. The answer is blue.
An aqueous potassium iodate ( KIO3
) solution is made by dissolving 531 g
of KIO3
in sufficient water so that the final volume of the solution is 4.30 L.
Calculate the molarity of the KIO3
solution.
[ KIO3
KIO
3
]=
The molarity of the KIO3 solution is 0.576 M.
KIO3 Molarity CalculationTo calculate the molarity of the KIO3 solution, we need to know the number of moles of KIO3 in the solution and the volume of the solution.
First, let's calculate the number of moles of KIO3:
Number of moles of KIO3 = Mass of KIO3 / Molar mass of KIO3
The molar mass of KIO3 is 214.00 g/mol (1 potassium atom with a molar mass of 39.10 g/mol, 1 iodine atom with a molar mass of 126.90 g/mol, and 3 oxygen atoms with a molar mass of 16.00 g/mol each).
Number of moles of KIO3 = 531 g / 214.00 g/mol
Number of moles of KIO3 = 2.48 mol
Now, we can calculate the molarity of the KIO3 solution:
Molarity = Number of moles of solute / Volume of solution in liters
Molarity = 2.48 mol / 4.30 L
Molarity = 0.576 M
Therefore, the molarity of the KIO3 solution is 0.576 M.
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After two emissions an isotope of oxygen-17 becomes a isotope of nitrogen-13. What are the two emissions
The two emissions required for oxygen-17 to become nitrogen-13 are a positron emission and a neutrino emission.
What is neutrino and a positron?A neutrino is a subatomic particle that is similar to an electron in many ways but differs in that it lacks an electrical charge and has a very small mass that might potentially be zero.
Positron is a particle with the same mass as an electron but has a positive charge.
The transformation of oxygen-17 to nitrogen-13 requires the emission of two particles: a positron (also called a positive beta particle) and a neutrino.
The first emission is the positron, which is a particle with the same mass as an electron but with a positive charge. During the emission, a proton in the oxygen-17 nucleus converts into a neutron, and the positron and a neutrino are produced. The positron quickly annihilates with an electron, releasing two gamma rays.
The second emission is the neutrino, which is a subatomic particle with a very small mass and no electrical charge. The neutrino is emitted during the decay of the nitrogen-13 nucleus as it transitions to its ground state.
Therefore, the two emissions required for oxygen-17 to become nitrogen-13 are a positron emission and a neutrino emission.
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H₂PO₂ +3 NaOH →
0.08 M NaOH
(green)
Na PO + 3 H₂O
If 25.0 mL of H₂PO, 0.16 M are required to titrate 150.0 mL of NaOH to the equivalence point, what is the molarity
of the NaOH?
0.16 M NaOH
(sky blue)
0.02 M NaOH
(yellow)
Answer:
The balanced chemical equation for the reaction between H₂PO₂ and NaOH is:
H₂PO₂ + 3 NaOH → Na₃PO₄ + 3 H₂O
Explanation:
From the equation, we can see that 1 mole of H₂PO₂ reacts with 3 moles of NaOH to produce 1 mole of Na₃PO₄ and 3 moles of H₂O.
The volume of NaOH used in the titration is 150.0 mL, which is equivalent to 0.150 L. The molarity of the H₂PO₂ solution used is 0.16 M, which means that 0.16 moles of H₂PO₂ were used in the titration.
According to the balanced equation, 1 mole of H₂PO₂ reacts with 3 moles of NaOH. Therefore, the number of moles of NaOH used in the titration is three times the number of moles of H₂PO₂ used:
Number of moles of NaOH = 3 × 0.16 = 0.48 moles
The volume of NaOH used is 0.150 L, so the molarity of NaOH can be calculated as follows:
Molarity of NaOH = Number of moles of NaOH / Volume of NaOH used
Molarity of NaOH = 0.48 moles / 0.150 L
Molarity of NaOH = 3.2 M
Therefore, the molarity of NaOH is 3.2 M, which is represented by the sky blue color.
How is the outer layer of earth different from the outer layer of Neptune
With a radius of 15,299.4 miles (24,622 kilometers), Neptune is about 4 times wider than Earth. If Earth have been the size of a nickel, Neptune would be about as big as a baseball.
From an common distance of 2.8 billion miles (4.5 billion kilometers), Neptune is 30 astronomical units away from the Sun.
What is the outermost layer of Neptune?Image end result for How is the outer layer of earth one-of-a-kind from the outer layer of Neptune
The outermost layer of Neptune is the atmosphere, forming about 5-10% of the planet's mass, and extending up to 20% of the way down to its core.
What are the three differences between Neptune and Earth?Image end result for How is the outer layer of earth distinct from the outer layer of Neptune
The extent of Neptune is 6.3 x 1013 km3. You could healthy fifty seven Earths inner Neptune and nevertheless have room to spare. A day on Earth is 24 hours, but a day on Neptune is 16 hours and 6 minutes. A yr on Earth is, um, 1 12 months obviously, whilst a year on Neptune is 164.79 years.
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