If you want to achieve a final concentration of 100 µg/mL of epinephrine in a 25 mL solution, when using a stock solution of 1 mg/mL and a pipette that delivers 20 drops/mL, you need to add 50 drops of your stock solution.
Explanation:Since we are asked to find the number of drops of stock solution required to achieve a final concentration of 100 µg/mL in a 25 mL solution, the first step is to convert the concentration of the stock solution to the same units, µg/mL. Hence, 1 mg/mL is equal to 1000 µg/mL. Further, we know that 1 mL of the stock solution contains 1000 µg of epinephrine, and our pipette delivers 20 drops/mL, so 1 drop of stock solution contains 1000 µg / 20 drops = 50 µg. Thus, if we need a 100 µg/mL concentration in 25 mL, we need a total of 100 µg/mL * 25 mL = 2500 µg of epinephrine. Therefore, to achieve this, we must add 2500 µg / 50 µg/drop = 50 drops of our stock solution. Hence,
50 drops
of the stock solution should be added to achieve the desired concentration.
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To achieve a final concentration of 100 µg/mL of epinephrine in 25 mL of Locke's solution, you need to add 50 drops of the 1 mg/mL stock solution. The dilution factor for one drop of the stock solution in the muscle bath is 500
a) To determine the required number of drops to achieve a specific concentration in Locke's solution, we follow these steps:
Calculate the total amount of epinephrine needed: With a final concentration of 100 µg/mL in 25 mL, the total amount of epinephrine necessary is:b) Dilution Factor
To calculate the dilution factor, we need to consider how much one drop dilutes in the 25 mL smooth muscle bath:Volume of one drop:
1 mL / 20 drops = 0.05 mL/drop
The dilution factor, therefore, is the ratio of the final volume to the volume of one drop:25 mL / 0.05 mL = 500
The correct dilution factor is 500.
Therefore, you must add 50 drops of the stock epinephrine solution to the muscle bath in Locke's solution to achieve the desired concentration of 100 µg/mL and dilution factor of 500.
Complete question.
Assume that you have a stock solution of epinephrine at a concentration of 1mg/ml. Further assume that there are 20 drops/ml.
a. Calculate the number of drops of the stock solution that must be added to a smooth muscle bath containing 25 ml of Locke's solution so that the final concentration of epinephrine in the muscle bath will be 100 µg/mL.
b. Compute the dilution factor which describes the extent to which a single drop of stock drug solution is diluted when added to the smooth muscle bath.
Use the References to access important val A piece of an unknown metal has a volume of 19.7 mL and a mass of 427.0 grams. The density of the metal is g/mL A piece of the same metal with a mass of 64.9 grams would have a volume of Submit Answer
Answer:
The density of the metal is 21.675 g/mL.
The volume of metal with mass of 64.9 grams is 2.994 mL.
Explanation:
Density is defined as mass present in unit volume of the substance.
[tex]Density=\frac{Mass}{Volume}[/tex]
Mass of unknown metal = m = 427.0 g
Volume of the unknown metal = v = 19.7 mL
Density of the unknown metal = d
[tex]d=\frac{m}{v}=\frac{427.0 g}{19.7 mL}=21.675 g/mL[/tex]
Mass of the same unknown metal = M = 64.9 g
Volume of same unknown metal with mass M = V
Density of the metal = d = 21.675 g/mL
[tex]21.675 g/ mL=\frac{64.9 g}{V}[/tex]
V = 2.994 mL
An aqueous solution of sulfuric acid has a composition of 25.0 wt% sulfuric acid and a specific gravity of 1.22. Calculate the volume of solution that contains 245 kg of sulfuric acid.
Answer: The volume of solution is [tex]8.03\times 10^5mL[/tex]
Explanation:
The relationship between specific gravity and density of a substance is given as:
[tex]\text{Specific gravity}=\frac{\text{Density of a substance}}{\text{Density of water}}[/tex]
Specific gravity of sulfuric acid solution = 1.22
Density of water = 1.00 g/mL
Putting values in above equation we get:
[tex]1.22=\frac{\text{Density of sulfuric acid solution}}{1.00g/mL}\\\\\text{Density of sulfuric acid solution}=(1.22\times 1.00g/mL)=1.22g/mL[/tex]
We are given:
25% (m/m) sulfuric acid solution. This means that 25 g of sulfuric acid is present in 100 g of solution
Conversion factor: 1 kg = 1000 g
Mass of solution having 254 kg or 245000 g of sulfuric acid is calculated by using unitary method:
If 25 grams of sulfuric acid is present in 100 g of solution.
So, 245000 grams of sulfuric acid will be present in = [tex]\frac{100}{25}\times 245000=980000g[/tex]
To calculate volume of a substance, we use the equation:
[tex]\text{Density of substance}=\frac{\text{Mass of substance}}{\text{Volume of substance}}[/tex]
Density of solution = 1.22 g/mL
Mass of Solution = 980000 g
Putting values in above equation, we get:
[tex]1.22g/mL=\frac{980000g}{\text{Volume of solution}}\\\\\text{Volume of solution}=\frac{980000g}{1.22g/mL}=8.03\times 10^5mL[/tex]
Hence, the volume of solution is [tex]8.03\times 10^5mL[/tex]
How many milliliters of a 1:5000 w/v solution of the preservative benzalkonium chloride can be made from 125 mL of a 0.2% w/v solution of the preservative? a. 1250 mL b. 2500 mL C. 625 mL d. 1875 ml
Final answer:
To determine the volume of a 1:5000 w/v solution that can be made from 125 mL of a 0.2% w/v solution of benzalkonium chloride, we calculate the mass of the solute in the initial solution and divide it by the concentration of the desired dilute solution, giving us 1250 mL.
Explanation:
To calculate the target volume of a 1:5000 w/v solution from a 0.2% w/v solution of benzalkonium chloride, we first need to understand the concentration terms. A 0.2% w/v solution means 0.2 g of solute is present in every 100 mL of solution. For a 1:5000 w/v solution, there is 1 g of solute in 5000 mL of solution, or essentially y, 0.0002 g/mL (1 g / 5000 mL).
We then figure out how much benzalkonium chloride is in the initial 125 mL of the 0.2% solution. Since 0.2% w/v is equivalent to 0.2 g/100 mL, we have 0.2 g in 100 mL, hence in 125 mL, we'll have 0.25 g (since 125 mL is 1.25 times 100 mL).
To work out how much of the 1:5000 solution we can make with 0.25 g, we use the concentration of the 1:5000 solution, which is 0.0002 g/mL. Dividing the total available mass of solute (0.25 g) by the concentration (0.0002 g/mL), we get 1250 mL. Thus, the answer is a. 1250 mL.
An ideal gas with MW = 30 is flowing at a steady rate through a circular pipe (cross-section area of 57.8 cm^2) at a temperature of 1.60 × 10^2 °C and pressure of 49.3 psig. The volumetric flow rate is 940 L/min, what is the molar flow rate (mol/s)?
Answer:
n = 1.48 mol/s
Explanation:
ideal gas:
PV = RTn⇒ n = PV/RT
∴ T = 1.60 E2 °C = 160°C = 433 K
∴ R = 0.082 atm.L/K.mol
∴ P = 49.3 psig * ( atm/ 14.6959psig ) = 3.35 atm
∴ V = 940 L/min
⇒ n = (( 3.35 )*( 940 )) / (( 0.082 )*( 433 ))
⇒ n = 88.813 mol/min * ( min / 60s )
⇒ n = 1.48 mol/s
Be sure to answer all parts. Write a balanced equation (including physical states) for the following reaction: Sodium carbonate, upon heating, produces sodium oxide and carbon dioxide.
Answer:
I think it would be:
NaCO3 (s)-->Na2O (s) + CO2 (g)
The balanced chemical equation when Sodium carbonate heated to produces sodium oxide and carbon dioxide is as,
[tex]Na_{2} CO_{3} (s)[/tex] → [tex]Na_{2} O (s) + CO_{2} (g)[/tex]
The above reaction is thermal decomposition reaction.
What is thermal decomposition reaction?The chemical decomposition caused by the heat is called thermal decomposition reaction.It is also known as thermolysis.Example: [tex]Na_{2} CO_{3} (s)[/tex] → [tex]Na_{2} O (s) + CO_{2} (g)[/tex]What is decomposition reaction?The reaction in which chemical species or reactant break down into smaller part.learn about decomposition reaction,
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Butane is burned as a lighter fluid in disposable lighters. Write a balanced equation for the complete oxidation reaction that occurs when butane (C4H10) burns in air. Use the smallest possible integer coefficients.
Answer:
The balanced equation for the complete oxidation reaction uses 2 moles of butane and 13 moles of Oxygen.
Explanation:
The oxidation of butane is shown in the following picture. As it is a complete combustion, the products of this reaction are carbon dioxide and water.
Butane (C₄H₁₀) combusts in the presence of oxygen (O₂) to produce carbon dioxide (CO₂) and water (H₂O). The balanced reaction is: 2C₄H₁₀(g) + 13O₂(g) -> 8CO₂(g) + 10H₂O(g). This is a combustion reaction, which is exothermic and releases heat and light.
Explanation:The question is asking for the balanced combustion reaction of butane, which is burned as a lighter fluid in disposable lighters. In the presence of sufficient oxygen, butane (C₄H₁₀) combusts to produce carbon dioxide (CO₂) and water (H₂O). The reaction can be represented and balanced as follows:
2C₄H₁₀(g) + 13O₂(g) -> 8CO₂(g) + 10H₂O(g)
This reaction is an example of a combustion reaction, where a hydrocarbon, like butane, burns in the air to produce carbon dioxide and water. It's also an exothermic reaction, releasing energy in the form of heat and light, which is what makes butane useful as a lighter fluid.
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The oxidation of the sugar glucose, C6H12O6, is described by the following equation. C6H12O6(s) + 6 O2(g) → 6 CO2(g) + 6 H2O(l) ΔH = −2802.5 kJ/mol The metabolism of glucose gives the same products, although the glucose reacts with oxygen in a series of steps in the body.
(a) How much heat in kilojoules can be produced by the metabolism of 18.1 g of glucose?
(b) How many Calories can be produced by the metabolism of 18.1 g of glucose?
Answer:
(a) 282 kJ
(b) 67.4 Calories
Explanation:
(a) The molar enthalpy, ΔH = −2802.5 kJ/mol, means that the heat produced by the reaction is 2802.5 kJ per mol of glucose.
We can multiply the enthalpy by the number of moles of glucose to get the heat produced by the metabolism. Grams of glucose will be converted to moles using the molar mass of glucose (180.156 g/mol):
(18.1 g)(mol/180.156g)(2802.5 kJ/mol) = 282 kJ
(b) Using the result we obtained above, kJ will be converted to Calories using the conversion factor of 4.184J = 1 cal. Calorie with a capital C is the same as a kilocalorie.
(282 kJ)(1 cal/4.184J) = 67.4 kcal = 67.4 Calories
Answer:
For a: The amount of heat produced for given amount of glucose is -283.05 kJ
For b: The amount of heat produced for given amount of glucose is -67648.9 Cal
Explanation:
To calculate the number of moles, we use the equation:
[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex]
Given mass of glucose = 18.1 g
Molar mass of glucose = 180.16 g/mol
Putting values in above equation, we get:
[tex]\text{Moles of glucose}=\frac{18.1g}{180.16g/mol}=0.101mol[/tex]
The given chemical reaction follows:
[tex]C_6H_{12}O_6(s)+6O_2(g)\rightarrow 6CO_2(g)+6H_2O(l);\Delta H=-2802.5kJ/mol[/tex]
For a:By Stoichiometry of the reaction:
When 1 mole of glucose is reacted, the amount of heat released is 2802.5 kJ
So, when 0.101 moles of glucose is reacted, the amount of heat released is [tex]\frac{2802.5}{1}\times 0.101=283.05kJ[/tex]
Hence, the amount of heat produced for given amount of glucose is -283.05 kJ
For b:To convert the heat produced in kilo joules to calories, we use the conversion factor:
1 kJ = 239 Cal
So, [tex]-283.05kJ\times (\frac{239Cal}{1kJ})=-67648.9Cal[/tex]
Hence, the amount of heat produced for given amount of glucose is -67648.9 Cal
You are given a solution that is 518 mM lactose. You need to make up 4.5 L of 16.7 mM solution. What volume do you need to transfer from your stock?
Answer:
The volume you need to transfer from the stock solution is 0.145 l
Explanation:
Since the number of moles of lactose in the volume of stock solution that you transfer will be the same as the number of moles of lactose in the final solution, you can use this expression:
number of moles in volume to transfer = number of moles in the final solution
Since number of moles = concentration * volume (if the concentration is expressed in molarity), then:
Ci * Vi = Cf * Vf
where:
Ci = concentration of the stock solution.
Vi = volume of the stock solution to be transferred.
Cf = concentration of the final solution
Vf = volume of the final solution
Then, replacing with the data:
518 mM * Vi = 16.7 mM * 4.5 l
Vi = 16.7 mM * 4.5 l / 518 mM
Vi = 0.145 l or 145 ml
Notice that any concentration unit can be used, as long as the units of the concentration of the stock and final solution are the same.
How many bonds can each of the elements below form with neighboring atoms in a compound? CHON BOSCH
Answer:
Maximum number of bonds each of the elements can form:
C: 4 bonds, H: 1 bonds, O: 2 bonds, N: 3 bonds, B: 3 bonds, S: 4 bonds.
Explanation:
The elements C, O, S and N follows the octet rule which establishes that every atom must have eight valence electrons to be stable. Thus, Carbon has 4 valence electrons, so could link 4 atoms. Nitrogen has 5 valence electrons, so could link 3 atoms. Oxygen and Sulfur have 6 valence electrons, so could link 2 atoms. Hydrogen and Boron are exceptions to the octet rule, therefore, the first one only needs 2 valence electron to be stable and the second one only needs 6 valence electron to be stable.
Final answer:
The number of covalent bonds an element can form generally corresponds with its group on the periodic table and its need to complete an octet, except for hydrogen which needs only two electrons. Group 4A elements like carbon form four bonds, Group 5A like nitrogen three, and Group 6A like oxygen and sulfur two. Boron typically forms three bonds but can form compounds or ions to achieve stability.
Explanation:
The number of covalent bonds an element can form is often related to its group number on the periodic table and its need to complete an octet of valence electrons. For example:
Carbon (C) is in group 4A, has four valence electrons, and tends to form four covalent bonds.
Hydrogen (H) needs two electrons for a full outer shell, so it forms one covalent bond.
Oxygen (O) is in group 6A with six valence electrons and forms two covalent bonds.
Nitrogen (N) is in group 5A, has five valence electrons, and forms three covalent bonds.
Boron (B) usually forms three covalent bonds, leaving it with six valence electrons.
Sulfur (S) is able to form two covalent bonds like oxygen, due to its position in group 6A.
Elements such as boron are unique in their bonding behaviors, often forming compounds or ions in order to achieve a more stable configuration, such as in the borohydride anion (BH4-). Transition elements and inner transition elements, with their d and f electrons, don't always follow the octet rule and can have variable bonding capacities.
What is the concentration, in millimolar, of a 1 mg/ml solution of NaCl (molecular weight = 58 Da)?
Explanation:
Relation between molarity and molar mass is as follows.
Molarity = [tex]\frac{mass}{\text{molar mass}} \times \frac{1000}{V (in ml)}[/tex]
It is given that mass is 1 mg/ml which is also equal to [tex]10^{-3}[/tex] g.
Molecular mass = 58 Da = 58 g/mol
Volume = 1 ml
Therefore, calculate molarity as follows.
Molarity = [tex]\frac{mass}{\text{molar mass}} \times \frac{1000}{V (in ml)}[/tex]
= [tex]\frac{10^{-3}g}{58 g/mol} \times \frac{1000}{1 ml}[/tex]
= 0.0172 molar
It is known that 1 molar equals 1000 millimolar.
So, 0.0172 molar = [tex]0.0172 molar \times \frac{1000 millimolar}{1 molar}[/tex]
= 17.2 millimolar
Thus, we can conclude that the concentration of given solution is 17.2 millimolar.
What is the mass of a proton in Gigagrams? ) 1.67 10-39Gg C ) 1.67 10-33 Gg D) 1.67 10-30G
Answer: The mass of proton is [tex]1.67\times 10^{-33}Gg[/tex]
Explanation:
Proton is one of the sub-atomic particle which is present in the nucleus of the atom.
We know that:
Mass of proton = [tex]1.67\times 10^{-27}kg[/tex]
To convert this into Giga grams, we use the conversion factor:
[tex]1Gg=1\times 10^6kg[/tex]
Converting the given value into Giga grams, we get:
[tex]\Rightarrow 1.67\times 10^{-27}kg\times \frac{1Gg}{1\times 10^6kg}=1.67\times 10^{-33}Gg[/tex]
Hence, the mass of proton is [tex]1.67\times 10^{-33}Gg[/tex]
Identify the sample and analyte in each of the scenarios.
(a) Determination of the lead content in paint. lead paint
(b) Analysis of the nitrate content of soil near a local water source. soil nitrate
(c) Measurement of the citric acid found in a lime.
Identify the following as either sample or analyte.
(1) lead
(2) paint chips
(3) soil
(4) nitrate
(5) lime wedge
(6) citric acid
Answer:
a) Analyte: lead. Sample: paint.
b) Analyte: nitrate. Sample: soil.
c) Analyte: citric acid. Sample: Lime
1) Lead: Analyte.
2) Paint chips: Sample.
3) Soil: Sample.
4) Nitrate: Analyte.
5) Lime wedge: Sample.
6) Citric acid: Analyte.
Explanation:
A sample is a portion of material selected from a larger quantity of material while an analyte is the chemical of the system that will be analysed.
Thus:
a) Analyte is lead while you must take a sample of paint to analyze this lead.
b) Analyte is the nitrate while sample must be soil.
c) Analyte is citric acid and lime is the sample
1) Lead: Analyte.
2) Paint chips: Sample.
3) Soil: Sample.
4) Nitrate: Analyte.
5) Lime wedge: Sample.
6) Citric acid: Analyte.
Final answer:
In scenarios (a) to (c), the samples are paint chips, soil, and lime wedge, respectively, and the analytes are lead, nitrate, and citric acid, respectively. Item identifications are lead and nitrate as analytes, and paint chips, soil, and lime wedge as samples.
Explanation:
In analytical chemistry, the analyte is the substance whose chemical content is being measured or analyzed, and the sample is the material or product that contains the analyte. Here are the identifications for each scenario:
(a) The sample is the paint chips and the analyte is lead.(b) The sample is the soil and the analyte is nitrate.(c) The sample is the lime wedge and the analyte is citric acid.To clarify, here are the identifications for each item listed:
(1) Analyte: lead(2) Sample: paint chips(3) Sample: soil(4) Analyte: nitrate(5) Sample: lime wedge(6) Analyte: citric acidCalculating molarity using solute moles A chemist prepares a solution of sodium chloride (NaCl) by measuring out 6.89 mol of sodium chloride into a 200 ml volumetric flask and filling the the mark with water. Calculate the concentration in mol/L of the chemist's sodium chloride solution. Round your answer to 3 significant digits. X 5 ? Explanation Check
Answer: Concentration of the chemist's sodium chloride solution is 34.4 mol/L.
Explanation:
Molarity of a solution is defined as the number of moles of solute dissolved per Liter of the solution.
[tex]Molarity=\frac{n\times 1000}{V_s}[/tex]
where,
n= moles of solute
[tex]V_s[/tex] = volume of solution in ml
Given : moles of [tex]NaCl[/tex] = 6.89
volume of solution = 200 ml
Putting in the values we get:
[tex]Molarity=\frac{6.89\times 1000}{200}=34.4mol/L[/tex]
Thus the concentration of the chemist's sodium chloride solution is 34.4 mol/L.
Which of the following statistical metrics is an appropriate measure of the variability of data around the mean? standard deviation O mode width O median
Answer:
Variability of data around the mean is best expressed through the standard deviation.
Explanation:
We have some statistical metrics, and we need to find the best measure of the variability of data around the mean.
First variable is mode. Mode of a set of data values is the value that appears most often. It means the most frequent data.
Second variable is Median. The median is a simple measure of central tendency. It is located around 50% of data range.
Third variable is standard deviation. The standard deviation is found by taking the square root of the average of the squared deviations of the values subtracted from their average value. It means, it will show the dispersion of data around the average value.
According to the definition presents for the three variables, Standard deviation is the most appropriate measure of variability of data around the mean.
Answer:
Correct answer is: Variability of data around the mean is best expressed through the standard deviation.
Explanation:
Got it correct on Plato Hope This helped :D
Vehicle gasoline has many slightly different compositions depending on local laws. However, on average it has a density of 0.737 kg/L. This morning you pumped 7.2 gallons of gasoline in order to fill up your fuel tank. How much mass have you added to your car, in kilograms?
1 gal = 3.785 L
Use appropriate Sig Figs in answer!
Answer: 20.1 kg.
Explanation:
To calculate mass of a substance, we use the equation:
[tex]\text{Density of substance}=\frac{\text{Mass of substance}}{\text{Volume of substance}}[/tex]
We are given:
Density of gasoline = [tex]0.737kg/L[/tex]
Volume of gasoline = [tex]7.2gallons=7.2\times 3.785L=27.252L[/tex] (Conversion factor: [tex]1gal=3.785L[/tex] )
Putting values in above equation, we get:
[tex]0.737kg/L=\frac{\text{Mass of gasoline}}{27.252L}\\\\\text{Mass of gasoline}=20.084kg[/tex]
The rule apply for multiplication and division is :
The least precise number present after the decimal point determines the number of significant figures in the answer, thus the answer musty have three significant digits.
Hence, the mass added is 20.1 kg.
A chemist must prepare 200.0 mL of hydrochloric acid solution with a pH of 0.60 at 25 °C. He will do this in three steps: • Fill a 200.0 mL volumetric flask about halfway with distilled water. • Measure out a small volume of concentrated (6.0M) stock hydrochloric acid solution and add it to the flask. • Fill the flask to the mark with distilled water. Calculate the volume of concentrated hydrochloric acid that the chemist must measure out in the second step. Round your answer to 2 significant digits. mL X 5 ?
Answer:
In the second step, the chemist must measure 8.3 ml of concentrated acid
Explanation:
The concentration of the final solution can be obtained using the pH value:
pH = -log[H] = 0.60
[H] = 10^(-0.60) = 0.25 M
Then, the final concentration of HCl will be 0.25 M because HCl is a monoprotic acid, which means that HCl only has one hydrolyzable proton. Therefore: [HCl] = [H].
The number of moles of HCl in the final solution will be equal to the number of moles present in the volume taken from the stock solution:
n° of moles in the volume taken from stock solution = n° moles in the final solution.
The number of moles can be calculated as follows:
number of moles = concentration * volume
Then:
Ci * Vi = Cf * Vf
where
Ci = concentration of the stock solution
Vi = volume taken from the stock solution
Cf = concentration of the final solution
Vf = volume of the final solution
Replacing with the data, we can obtain Vi:
6.0 M * Vi = 0.25 M * 200.0 ml
Vi = 8.3 ml
If pressure p A + B/T+C/T, where A, B, and C are constants, and T is the temperature. What is the unit of A, B and C? Problem 2 (3 pts): If a system is at steady state, do properties vary with time? Can properties vary with location under steady state?
Answer:
The unit of A must be 'atm', and the units of B and C must be 'atmxK'.
If a system is at steady state it means the properties do not vary over time.
Explanation:
The units of pressure must be atm, bar, Pa or mmHg. If we use the atm unit the result of the equation should be the pressure in 'atm'. Thus, the unit of A must be 'atm', and the units of B and C must be 'atmxK'. So, If we replace the equation with the temperatures (T) in Kelvin (K) the result will be in 'atm'.
[tex]P (atm) = A(atm) + \frac{B(atm.K)}{T(K)} + \frac{C(atm.K)}{T(K)}[/tex]
Problem 2: If a system is at steady state it means the properties do not vary over time. This is the definition of a steady state. Also, every particular steady state will define their own properties but each steady state will no vary their properties over time.
A cylinder with a movable piston records a volume of 12.6L when 3.0 mol of oxygen is added. The gas in the cylinder has a pressure of 5.83 atm. The cylinder develops a leak and the volume of gas is now recorded to be 12.1 L at the same pressure. How many moles of oxygen are lost?
Answer : The moles of oxygen gas lost are 2.88 mole
Explanation :
According to the Avogadro's Law, the volume is directly proportional to the number of moles of the gas at constant pressure and temperature.
[tex]V\propto n[/tex] (At constant temperature and pressure)
or,
[tex]\frac{V_1}{V_2}=\frac{n_1}{n_2}[/tex]
where,
[tex]V_1[/tex] = initial volume of oxygen gas = 12.6 L
[tex]V_2[/tex] = final volume of oxygen gas = 12.1 L
[tex]n_1[/tex] = initial moles of oxygen gas = 3.0 mole
[tex]n_2[/tex] = final moles of oxygen gas = ?
Now put all the given values in the above formula, we get the final moles of oxygen gas.
[tex]\frac{12.6L}{12.1L}=\frac{3.0mole}{n_2}[/tex]
[tex]n_2=2.88mole[/tex]
Therefore, the moles of oxygen gas lost are 2.88 mole
Which model of election configuration is the most accurate? The quantum mechanical atomic model The Rutherford atomic model The Bohr atomic model O Plum pudding atomic model The quantum gravity atomic model
Answer:
Quantum mechanical atomic model.
Explanation:
The first model of electronic configuration was given by Bohr's model.
The most accurate model of electronic configuration is the quantum mechanical atomic model.
Bohr's model has various limitations:
1. It does not explain the Zeeman effect and stark effect.
2. It is not valid for multi-electron system.
3. Heisenberg uncertainty principle is not followed by this model
The quantum mechanical atomic model explains all the four quantum numbers for the electronic configuration of an atom in the periodic table.
The quantum mechanical atomic model considered the Heisenberg uncertainty principle.
Answer:
Quantum mechanical atomic model.
Explanation:
The atom model given by quantum mechanics is the most modern, precise and complex, based on the mathematical form of the atomic structure.
Quantum theory states that matter has properties associated with waves, which is why the atom model was based on this theory. The so-called “Uncertainty Principle” states that the electron has no exact position in the electrosphere, no definite speed and direction. This is why the Bohr atom, with electrons spinning in circular orbits, is surpassed by the quantum model.
13. Which ONE of the following is a chemical process? A. The liquid propane in a gas grill burns in a flame. B. Salt (sodium chloride) dissolves in water. C. Ice melts to form liquid water. D. The liquid propane in a gas grill evaporates because the user left the valve open. E. All of the above are chemical processes.
Answer:
A. The liquid propane in a gas grill burns in a flame.
Explanation:
Chemical changes is the change which occur when the substance combines with the another to form a completely new substance.
Considering Options B, C and D, the identity of each specie is not changed but the state is changed and thus, these are physical changes.
On the other hand, Option A, when propane is being burnt in the flame , it changes to gas and its identity is lost. Thus, is a chemical change.
The correct answer to the student's question is A, as the burning of liquid propane in a gas grill is a chemical process that results in the formation of new substances, which is the definition of a chemical change.
Explanation:The student's question pertains to identifying a chemical process from a list of options. To differentiate between physical and chemical changes, we recall that a physical change is a change in the state or form of a substance without changing its chemical composition, whereas a chemical change results in the formation of one or more new substances with different properties.
A. The liquid propane in a gas grill burns in a flame. This is a combustion reaction, where propane reacts with oxygen to produce carbon dioxide, water, and heat, making it a chemical process.B. Salt (sodium chloride) dissolving in water is a physical process, as the chemical composition of salt remains unchanged.C. Ice melting to form liquid water is a physical process because the chemical identity of the substance does not change.D. The liquid propane in a gas grill evaporating is also a physical process, as it involves the phase change from liquid to gas without altering the chemical composition of the propane.E. Not all of the listed options are chemical processes; hence, this option is incorrect.Therefore, the correct answer to the question is option A, where the burning of liquid propane in a gas grill is a chemical process resulting in new substances.
A balloon filled with helium has a volume of 4.6 x 103 L at 31°C. What volume will the balloon occupy at 56°C if the pressure surrounding the balloon remains constant? Be sure to answer all parts. Enter your answer in scientific notation. x 10 (select) ^L
Answer:
5x10^3 L
Explanation:
Charle's Law states that the volume of a fixed amount of gas maintained at constant pressure is directly proportional to the absolute temperature of the gas, for a constant amount of gas we can write:
[tex]\frac{V1}{T1}=\frac{V2}{T2}[/tex]
As the pressure of the balloon doesn't change, we can use Charle's Law to solve the problem. Firs we change the given temperatures to absolute temperature units ( °K), using the following relations:
°K=273,15+°C
Therefore:
V1=4.6 x 10^3 L, T1=273,15+31=304,15°K
V2=?, T2=273,15+56=329,15°K
[tex]V2=\frac{V1T2}{T1}=\frac{4.6*10^3*329,15}{304,15}=4978,1L=5*10^3L[/tex]
The new volume of the balloon is 5x10^3 L.
The volume of a helium-filled balloon at 56°C under constant pressure can be calculated using Charles's Law by converting temperatures to Kelvins and using the volume-temperature direct proportionality relationship.
Explanation:The subject of this question involves the relationship between volume and temperature of a gas under constant pressure, described by Charles's Law. This law states that the volume of an ideal gas is directly proportional to its temperature (in Kelvins) when pressure is held constant. To use Charles's Law for calculating the new volume of a balloon, first, convert the temperatures from Celsius to Kelvins (K = °C + 273.15). The initial temperature is 31°C, which is 304.15K, and the final temperature is 56°C, which is 329.15K.
Apply Charles's Law using the formula V1/T1 = V2/T2. Let V1 be the initial volume (4.6 x 10³ L), T1 be the initial temperature (304.15K), V2 be the final volume, and T2 be the final temperature (329.15K). Solving for V2 gives:
V2 = (V1 x T2) / T1 = (4.6 x 10³ L x 329.15K) / 304.15K
Calculating this will give us the new volume V2 which we express in scientific notation.
What is the easiest way to make 250.0 mL of each of the following solutions if you begin with 250.0 ml. of 1.00M NaCl? a) 0.100 M NaCl b) 0.0100 M Naci c) 0.00100 M NaCl d) 0.000100 M NaCl e) 0.0000100 M Naci En Melation of
Answer:
The easiest way to make these solutions is preparing serial dilutions with dilution factor of 10.
Explanation:
In chemistry, a dilution is the way to reducing the concentration of a chemical adding more solvent.
To prepare the first 0,100 M NaCl from 1,00 M NaCl:
You must take an aliquot of 25,0 mL of 1,00 M NaCl and dilute until 250,0 mL. Thus, the concentration will decrease ten times until the expected concentration. The dilution factor is 10.
To prepare the second 0,0100 M of NaCl:
From 0,100 M NaCl take an aliquot of 25 mL an dilute until 250,0 mL. Thus, the concentration will decrease ten times.
So, to prepare each solution you must take the last one and dilute it in a dilution factor of 10.
I hope it helps!
In a five-fold serial dilution of a 20 ug/mL solution, all tube dilutions are 1/5. What is the substance concentration in the third tube of this series?
Answer:
In the third tube, the concentration is 0.16 ug/mL
Explanation:
In the first step, the solution is diluted by 5. Then, the concentration will be
20 ug/mL / 5 = 4 ug/mL
Then, in the second step this 4 ug / ml solution is diluted by a factor of five again:
4 ug /ml / 5 = 0.8 ug/mL
This solution is then diluted again by 5 and the concentration in the third tube will be then:
0.8 ug/mL / 5 = 0.16 ug/mL
Another way to calculate this is to divide the original concentration by the dilution factor ( 5 in this case) elevated to the number of dilutions. In this case:
Concentration in the third tube = 20 ug/mL / 5³ = 0.16 ug/mL
The partial pressure of CO2 gas above the liquid in a carbonated drink is 0.51 atm. Assuming that the Henry's law constant for CO2 in the drink is that same as that in water, 3.7 x 10-2 mol/L atm, calculate the solubility of carbon dioxide in this drink. Give your answer to 3 decimal places.
Answer: The molar solubility of carbon dioxide gas is 0.002 M
Explanation:
Henry's law states that the amount of gas dissolved or molar solubility of gas is directly proportional to the partial pressure of the liquid.
To calculate the molar solubility, we use the equation given by Henry's law, which is:
[tex]C_{CO_2}=K_H\times p_{liquid}[/tex]
where,
[tex]K_H[/tex] = Henry's constant = [tex]3.7\times 10^{-2}mol/L.atm[/tex]
[tex]p_{CO_2}[/tex] = partial pressure of carbonated drink = 0.51atm
Putting values in above equation, we get:
[tex]C_{CO_2}=3.7\times 10^{-2}mol/L.atm\times 0.51atm\\\\C_{CO_2}=1.887\times 10^{-2}mol/L=0.002M[/tex]
Hence, the molar solubility of carbon dioxide gas is 0.002 M
Answer:
0.019 mol/L
Explanation:
Given data
Partial pressure of CO₂ above the liquid in a carbonated drink (P): 0.51 atmHenry's law constant for CO₂ (k): 3.7 × 10⁻² mol/L . atmSolubility of carbon dioxide in the drink (C): ?According to Henry's law, the solubility of a gas in a liquid is proportional to its partial pressure.
C = k × P
C = (3.7 × 10⁻² mol/L . atm) × 0.51 atm
C = 0.019 mol/L
maximum heat transfer in heat exchanger happend in :
a) Turbulant
b) Counter current
c) Co-current
Answer:
b) Counter current
Explanation:
In mechanical, chemical, nuclear and other systems, it happens that heat must be transferred from one place to another or from one fluid to another. Heat exchangers are the devices that allow you to perform this task the types of exchangers are presented of heat as a function of flow: parallel flow; counterflow; cross flow.
Among the main reasons why exchangers are used
Heat are as follows:
• Heat a cold fluid using a fluid with a higher temperature.
• Reduce the temperature of a fluid by means of a fluid with a lower temperature.
• Bring the fluid to the boiling point using a fluid with a higher temperature.
• Condense a fluid in a gaseous state by means of a cold fluid
A backflow occurs when the two fluids flow in the same direction but in opposite way. Each of the fluids enters the exchanger through different ends Since the fluid with less temperature goes backflow from the heat exchanger at the end where the fluid enters with higher temperature, the temperature of the coldest fluid will approach the temperature of the inlet fluid.
This type of exchanger turns out to be more efficient than the other two types mentioned above. In contract with the exchanger parallel flow heat, the counterflow exchanger may have the highest temperature in the cold fluid and the lower temperature in the hot fluid after heat transfer in the exchanger.
Be careful with turbulent that it is not a type of exchanger but a system in which a fluid is found.
Show the conversion factor from Patolbf/ft2is 0.02089.
Explanation:
1 Pascal = 1 N/m²
To convert Pa to lbf/ft²
So, the conversion of N to pound force (lbf) is shown below as:
1 N = 0.224809 pound force (lbf)
The conversion of m² to ft² is shown below:
1 m² = 10.7639 ft²
So,
[tex]1\ Pa=\frac {1\ N}{1\ m^2}=\frac {0.224809\ lbf}{10.7639\ ft^2}
1 Pa = 0.02089 lbf / ft²
Hence proved.
Perform the following calculation, giving the answer in the correct number of significant digits. (1.145 x 109 g/mol) (0.0035 mol)/(8.57 x 10 g/mL)=
Answer:
The answer is 0.005097 mL.
Explanation:
Significant figures : The figures in a number which express the value of the magnitude of a quantity to a specific degree of an accuracy is known as significant digits.
Given :
[tex]x=\frac{(1.145 x 109 g/mol)\times (0.0035 mol)}{(8.57 x 10 g/mL)}[/tex]
[tex]x=\frac{0.4368 g}{8.57\times 10 g/mL}=0.005097053 mL[/tex]
[tex]x=0.005097053 mL\approx 0.005097 mL[/tex]
How many neutrons and protons are there in the nuclei of the following atoms. a. Li-7 b. O-16 c. Th-232 d. Pu-239
Answer:
a.
P = 3 , N = 4
b.
P = 8 , N = 8
c.
P = 90 , N = 142
d.
P = 94 , N = 145
Explanation:
Mass number = Number of protons + Number of neutrons
Also,
Atomic number = Number of protons
Li - 7
Given, Mass number of Lithium = 7
For lithium, atomic number = 3
So,
Number of protons = 3
Number of neutrons = Mass number - Number of protons = 7 - 3 = 4
O - 16
Given, Mass number of oxygen = 16
For oxygen, atomic number = 8
So,
Number of protons = 8
Number of neutrons = Mass number - Number of protons = 16 - 8 = 8
Th - 232
Given, Mass number of Thorium = 232
For Thorium, atomic number = 90
So,
Number of protons = 90
Number of neutrons = Mass number - Number of protons = 232 - 90 = 142
Pu - 239
Given, Mass number of Plutonium = 239
For Plutonium, atomic number = 94
So,
Number of protons = 94
Number of neutrons = Mass number - Number of protons = 239 - 94 = 145
If 72.1 mL of 0.543 M H2SO4 completely titrates 39.0 mL of KOH solution, what is the molarity of the KOH solution? a. 0.317 M b. 0.502 M c. 1.00 M d. 2.01 M
Answer: The correct answer is Option d.
Explanation:
To calculate the molarity of base, we use the equation given by neutralization reaction:
[tex]n_1M_1V_1=n_2M_2V_2[/tex]
where,
[tex]n_1,M_1\text{ and }V_1[/tex] are the n-factor, molarity and volume of acid which is [tex]H_2SO_4[/tex]
[tex]n_2,M_2\text{ and }V_2[/tex] are the n-factor, molarity and volume of base which is KOH
We are given:
[tex]n_1=2\\M_1=0.543M\\V_1=72.1mL\\n_2=1\\M_2=?M\\V_2=39.0mL[/tex]
Putting values in above equation, we get:
[tex]2\times 0.543\times 72.1=1\times M_2\times 39.0\\\\M_2=2.01M[/tex]
Hence, the correct answer is Option d.
The concentration of the base is 2.01 M
What is neutralization?A neutralization reaction is a reaction that occurs between an acid and a base to yield salt and water only;
This reaction occurs as follows; H2SO4 + 2KOH ----->K2SO4 + H2O
From the titration formula;
concentration of acid CA = 0.543 M
volume of acid VA = 72.1 mL
concentration of baseCB = ?
volume of base VB= 39.0 mL
Number of moles of acid = 1
Number of moles of base = 2
Given that;
CAVA/CBVB = NA/NB
CAVANB = CBVBNA
CB = 0.543 M * 72.1 mL * 2/39.0 mL * 1
CB = 2.01 M
Learn more about molarity:https://brainly.com/question/4219437?
Which of the following is a diprotic acid? a. H2SO4 b. CH3COOH c. HC d. H3PO4
Answer:
The correct option is: A. H₂SO₄
Explanation:
Acid is a charged or a neutral molecule that is a proton donor and electron pair acceptors.
Acids can be classified into monoprotic acids and polyprotic acids.
Monoprotic acids are the acids that can release only one proton on dissociation.
Whereas, polyprotic acids are the acids that can release more than one proton on dissociation.
Diprotic acid is a type of polyprotic acid that can release two protons on dissociation. Example: H₂SO₄
A diprotic acid is an acid that contains two ionizable hydrogen atoms per molecule. Among the provided options, H2SO4 or sulfuric acid is such a diprotic acid. It ionizes in two stages, forming sulfates and hydrogen sulfates.
Explanation:The question asks about which of the given substances is a diprotic acid. Diprotic acids are those that contain two ionizable hydrogen atoms per molecule, which can release two protons or hydrogen ions. The ionization (release of protons) occurs in two steps: the first ionization generally takes place to a greater extent than the second.
By examining the chemical formulas of the options provided, we can identify H2SO4 (Sulfuric acid) as a diprotic acid. The ionization process works as following:
First ionization: H₂SO4 (aq) + H₂O(l) = H3O+ (aq) + HSO4¯(aq)Second ionization: HSO4¯ (aq) + H₂O(l) ⇒ H3O+ (aq) + SO4²- (aq)A significant attribute of diprotic acids like sulfuric acid is that they form both sulfates (e.g., Na2SO4) and hydrogen sulfates (e.g., NaHSO4).
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