10) In order to make spaghetti cook faster, a chef adds salt to water. How many moles of salt would he need to add to 1.0 kg water to make the water boil at 105 C? The Kb for water is 0.25°C/m. Assume i 2 for NaCl
The chef would need to add approximately 555.2 moles of salt NaCl to 1.0 kg of water to raise its boiling point to 105°C.
To determine how many moles of salt NaCl are needed to raise the boiling point of 1.0 kg of water to 105°C, we can use the concept of boiling point elevation and the colligative property of solutions.
Given data.
- Mass of water, [tex]\( m = 1.0 \) kg = \( 1000 \) g\\[/tex]
- Desired boiling point of water,[tex]\( T_{\text{new}} = 105 \)°C[/tex]
- Boiling point constant for water,[tex]\( K_b = 0.25 \) °C/m[/tex]
- Van't Hoff factor for NaCl [tex]\( i \) = 2 since NaCl dissociates completely into Na+ and Cl- ions in water[/tex]
First, calculate the change in boiling point [tex]\( \Delta T_b \)[/tex] using the formula for boiling point elevation
[tex]\[ \Delta T_b = i \cdot K_b \cdot m_{\text{salt}} \][/tex]
where.
- [tex]\( i \)[/tex] is the Van't Hoff factor,
- [tex]\( K_b \)[/tex] is the boiling point elevation constant,
- [tex]\( m_{\text{salt}} \)[/tex] is the molality of the salt in the solution.
To find [tex]\( m_{\text{salt}} \)[/tex], rearrange the equation:
[tex]\[ m_{\text{salt}} = \frac{\Delta T_b}{i \cdot K_b} \][/tex]
Calculate [tex]\( \Delta T_b \):[/tex]
[tex]\[ \Delta T_b = T_{\text{new}} - T_{\text{normal}} = 105 \text{°C} - 100 \text{°C} = 5 \text{°C} \][/tex]
Substitute the values into the equation.
[tex]\[ m_{\text{salt}} = \frac{5 \text{ °C}}{2 \cdot 0.25 \text{ °C/m}} \][/tex]
[tex]\[ m_{\text{salt}} = \frac{5}{0.5} \][/tex]
[tex]\[ m_{\text{salt}} = 10 \text{ mol/kg} \][/tex]
This molality [tex]10 mol/kg[/tex] represents the number of moles of salt per kilogram of solvent water.
To find the moles of salt [tex]\( n_{\text{salt}} \)[/tex] needed.
[tex]\[ n_{\text{salt}} = m_{\text{salt}} \cdot \frac{m_{\text{water}}}{M_{\text{water}}} \][/tex]
where.
[tex]- \( m_{\text{water}} \) is the mass of water[/tex],
[tex]- \( M_{\text{water}} \) is the molar mass of water.[/tex]
Calculate [tex]\( M_{\text{water}} \)[/tex].
[tex]\[ M_{\text{water}} = 18.015 \text{ g/mol} \][/tex]
Convert [tex]\( m_{\text{water}} \) to grams[/tex].
[tex]\[ m_{\text{water}} = 1000 \text{ g} \][/tex]
calculate [tex]\( n_{\text{salt}} \)[/tex].
[tex]\[ n_{\text{salt}} = 10 \text{ mol/kg} \cdot \frac{1000 \text{ g}}{18.015 \text{ g/mol}} \]\\[/tex]
[tex]\[ n_{\text{salt}} = 10 \cdot \frac{1000}{18.015} \text{ mol} \][/tex]
[tex]\[ n_{\text{salt}} \approx 555.2 \text{ mol} \][/tex]
Given the balanced equation: 3fe3+(aq) + al(s) → 3fe2+(aq) + al3+(aq)what is the total number of moles of electrons lost by 2 moles of al(s)?
was the supernova named after kepler becausae he was the first person to see it
Two clear solutions are placed in separate beakers. The first solution has a pH of 4, and the pH of the second solution is unknown. If the two solutions are mixed and the resulting pH is 5, the second solution must have
The pH of the second solution, given that the mixture of the two solution has a pH of 5, is 4.05
How to calculate the pH of the second solution?
First, we shall obtain the hydogen ion, [tex]H^+[/tex] of the first solution and the mixture solution. Details below:
For first solution:
pH of first solution = 4Hydrogen ion [tex]H^+[/tex] of first solution =?[tex]H^+ = Antilog (-4)\\\\H^+ = 0.0001\ M\\\\[/tex]
For mixture solution:
pH of mixture solution = 5Hydrogen ion [tex]H^+[/tex] of mixture solution =?[tex]H^+ = Antilog (-5)\\\\H^+ = 0.00001\ M\\\\[/tex]
Now, we shall obtain the [tex]H^+[/tex] of the second solution. Details below:
Hydrogen ion [tex]H^+[/tex] of first solution = 0.0001 MHydrogen ion [tex]H^+[/tex] of mixture solution = 0.00001 MHydrogen ion [tex]H^+[/tex] of second solution =?[tex]H^+[/tex] of second solution = [tex]H^+[/tex] of first solution - [tex]H^+[/tex] of mixture solution
= 0.0001 - 0.00001
= 0.00009 M
Finally, we shall calculate the pH of the second solution. Details below:
Hydrogen ion [tex]H^+[/tex] of second solution = 0.00009 MpH of second solution = ?pH = -Log Hydrogen ion [tex]H^+[/tex]
pH = -Log 0.00009
pH = 4.05
During which of the following processes does a glucose molecule break down into ethanol? Aerobic respiration, Alcoholic fermentation, Lactic acid fermentation, Photosynthesis
Answer:
Alcoholic fermentation
Explanation:
Alcoholic fermentation is an anaerobic process executed by yeasts, molds and some bacteria, which cause chemical changes in organic substances.
Alcoholic fermentation has the biological function of supplying energy to microorganisms in the absence of oxygen. To achieve this, the glucose molecules are dissociated and in this way the energy required to survive is obtained, producing ethanol and CO2 as products.
What effect does the specific heat capacity of water have on weather?
A. It keeps the temperatures on the coast milder.
B. It lowers the temperature at which ocean water freezes.
C. It stops convection currents from turning into storms.
D. It increases the effect of radiation heating of land.
What is MC2 minus 8?
A. MC2
B. 4
C. 9
D. None of the above
Answer:
d
Explanation:
If the number of particles in a mole is 6.022x1023, what is the total mass of 1.81×1024 particles of nitrogen gas (N2)?
A. 42 g
B. 4.2 g
C. 84 g
D. 8.4 g
Answer:
56 g
Explanation:
What mass of CaCO3 is required to react completely with 0.56 L of HCl?
What is the role of the activated complex in a chemical reaction?
This is a specific type of dipole-dipole force that exists between molecules with hydrogen atoms and molecules with nitrogen, oxygen or fluorine atoms
Answer:
This is a specific type of dipole-dipole force is known as Hydrogen bonding.
Explanation:
Hydrogen bonding (H-bonding) is an intermolecular force having partial ionic-covalent character. H-bonding takes place between a hydrogen atom attached with an electronegative atom( like : O, N and F) and lone pairs of electrons on an neighboring atoms.
Generally this type of bonding is observed where atoms like nitrogen , oxygen, fluorine attached to another molecule are present in neighbors of a hydrogen atom attached to other molecule. This bonding arises due to the interaction between the developed partial positive and negative charges on the hydrogen and electronegative atoms.
Which coefficients correctly balance the formula equation nh4no2(s)® n2(g) + h2o(l)?
2 is the coefficient that correctly balance the formula equation: NH4NO2 → N2 + H2O.
BALANCING CHEMICAL EQUATION:A balanced equation is one in which the atoms of each element on both sides of the equation are the same. According to this question, the following unbalanced decomposition reaction is given: NH4NO2 → N2 + H2OTo balance the equation, we make use of coefficients, which are numbers placed in front of the corresponding element or compound involved. The balanced equation is as follows: NH4NO2 → N2 + 2H2O. This equation shows that 2 is the coefficient placed in front of H2O to correctly balance the equation.Learn more about balancing chemical equations at: https://brainly.com/question/8062886
Which will diffuse through a membrane more rapidly, co or n2? assume that the samples contain only the most abundant isotopes of each element, 12c, 16o, and 14n?
Answer: Both will diffuse at the same rate
Explanation:
According to Graham's law, the rate of diffusion is inversely proportional to the square root of the relative molecular mass of the gases. The two gases, carbon II oxide and nitrogen gas has the same relative molecular mass (28). This implies that they must diffuse at the same rate through an membrane.
What is the final concentration of a solution prepared by diluting 35.0 ml of 12.0 m hcl to a final volume of 1.20 l? what is the final concentration of a solution prepared by diluting 35.0 ml of 12.0 m hcl to a final volume of 1.20 l?
The final concentration of the solution prepared by diluting 35.0 ml of 12.0 M HCl to a final volume of 1.20 L is 0.35 M.
Explanation:The final concentration of a solution prepared by diluting 35.0 ml of 12.0 M HCl to a final volume of 1.20 L can be calculated using the formula for dilution: M1V1 = M2V2. In this formula, M1 is the initial concentration, V1 is the initial volume, M2 is the final concentration, and V2 is the final volume.
Firstly, we convert the initial volume from ml to litres because the final volume is given in litres. So, 35.0 ml = 0.035 L. Therefore, the equation becomes: 12.0 M * 0.035 L = M2 * 1.20 L.
On rearranging the equation to solve for M2, the result is 0.35 M.
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For an equal mass of each substance, which one will require the least amount of heat to raise its temperature from 20°c to 30°c?
How can i use gland and hormone in a same sentence.?
In general as the similarity of the structure between solvent and solute increases the solubility does what
In the reaction: pb + 2ag+ → pb2+ + 2ag, the oxidizing agent is
Answer: The oxidizing agent for the given reaction is Silver.
Explanation:
Oxidizing agent is defined as the agent which helps the other substance to get oxidized and itself gets reduced. It undergoes reduction reaction in which a substance gains electrons. The oxidation state of this substance gets reduced and the substance gets reduced.
Reducing agent is defined as the agent which helps the other substance to get reduced and itself gets oxidized. It undergoes oxidation reaction in which a substance looses its electrons. The oxidation state of this substance gets increased and the substance gets oxidized.
For the given chemical reaction:
[tex]Pb+2Ag^+\rightarrow Pb^{2+}+2Ag[/tex]
The half reactions for the given above chemical reaction is:
Oxidation half reaction: [tex]Pb\rightarrow Pb^{2+}+2e^-[/tex]
Reduction half reaction: [tex]2Ag^++2e^-\rightarrow 2Ag[/tex]
As, lead is loosing electrons. So, it is getting oxidized and is considered as a reducing agent and silver is gaining electrons. So, it is getting reduced and is considered as an oxidizing agent.
Thus, the correct answer is silver.
a 45.0-ml sample of nitric acid solution is neutralized by 119.4 ml 0.200M NaOH solution. What is the molarity of the nitric acid solution?
mole used in a chemistry sentence
A sample of a compound contains 60.0 g C and 5.05 g H. Its molar mass is 78.12 g/mol. What is the compound’s molecular formula? CH C2H2 C6H6 C6H
A sample of a compound contains 60.0 g C and 5.05 g H.
divide by molar mass of C(12) and H(1) to get molar ratio
C: 60/12=5 and H: 5/1=5
so C:H=5:5=1:1
total molar mass=78
divide by 1C+1H to find the formula: 78/(12+1)=78/13=6
compound is C6H6
What is the volume, in liters, of 576 grams of so2 gas at stp?
The volume of 576 grams of SO₂ gas at STP is approximately [tex]\( 200 \, \text{L}} \).[/tex]
To find the volume of 576 grams of SO₂ gas at STP (Standard Temperature and Pressure), we can use the ideal gas law equation:
[tex]\[ PV = nRT \][/tex]
Where:
- P is the pressure (at STP, [tex]\( P = 1 \)[/tex] atm)
- V is the volume of the gas
- n is the number of moles of gas
- R is the ideal gas constant [tex](\( R = 0.0821 \, \text{Latm/(molK)} \))[/tex]
- T is the temperature in Kelvin (at STP, [tex]\( T = 273.15 \)[/tex] K)
First, calculate the number of moles [tex]\( n \)[/tex] of SO₂ gas:
1. Calculate the molar mass of SO₂:
- Atomic mass of S = 32.07 g/mol
- Atomic mass of O = 16.00 g/mol (there are 2 oxygen atoms)
- Molar mass of SO₂ = [tex]\( 32.07 + 2 \times 16.00 = 64.07 \)[/tex] g/mol
2. Convert grams of SO₂ to moles:
[tex]\[ n = \frac{\text{mass}}{\text{molar mass}} = \frac{576 \, \text{g}}{64.07 \, \text{g/mol}} \approx 9.00 \, \text{mol} \][/tex]
Now, use the ideal gas law to find the volume V:
[tex]\[ V = \frac{nRT}{P} \][/tex]
[tex]\[ V = \frac{9.00 \, \text{mol} \times 0.0821 \, \text{Latm/(molK)} \times 273.15 \, \text{K}}{1 \, \text{atm}} \][/tex]
[tex]\[ V \approx 200 \, \text{L} \][/tex]
The law of conservation of mass and how it applies to chemical changes
According to law of conservation of mass, mass is neither created nor destroyed and hence for a chemical reaction the mass of reactants and products is equal.
What is law of conservation of mass?According to law of conservation of mass, it is evident that mass is neither created nor destroyed rather it is restored at the end of a chemical reaction .
Law of conservation of mass and energy are related as mass and energy are directly proportional which is indicated by the equation E=mc².Concept of conservation of mass is widely used in field of chemistry, fluid dynamics.
Law needs to be modified in accordance with laws of quantum mechanics under the principle of mass and energy equivalence.This law was proposed by Antoine Lavoisier in the year 1789.
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During glycolysis, for every 6 moles of glucose that enter the pathway, how many moles of atp are used? how many moles atp are generated? how many moles of nadh are used? how many moles of pyruvate are made?
According to the Arrhenius theory a substance that yields hydrogen ions as the only ion in an aqueous solution is
According to the Arrhenius theory a substance that yields hydrogen ions as the only ion in an aqueous solution is Acid.
What are acids?Acids are those substances which are having pH range from 0 to 7.
According to the Arrhenius theory of acid and base, acids are those compounds which donate H⁺ ion or proton in the aqueous medium and bases are those substances which donate OH⁻ ion in the aqueous medium.
Example of Arrhenius acids are HCl, CH₃COOH, HNO₃, etc.
Hence, those substance which yields H⁺ ions is acids.
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Which example best demonstrates the benefit of understanding physical properties?
Engineers can design safer structures because they understand flammability of building materials
Engineers can design better bridges because they know how metal changes shape
Scientists can easily classify mixtures of unknown substances
Scientists can predict how well two substances will react
Answer: Engineers can design better bridges because they know how metal changes shape.
Explanation: Physical Properties are those properties which are also regarded as observable because they can be easily seen or observe through naked eyes like melting point etc.
These are those properties which do not change chemical identity of the species.
Thus out of the given options, only physical property is the change of shape of metal.
And the rest one represents the chemical property as chemical property are the one which changes the chemical identity of the substance.
The total amount of living tissue within a given trophic level is called the select one:
a. organic mass.
b. trophic mass.
c. energy mass.
d. biomass.
The correct term for the total amount of living tissue within a given trophic level is biomass. It encompasses the weight of all living organisms within an ecosystem or a specific trophic level. The answer to the student's query is thus d. biomass.
Explanation:The total amount of living tissue within a given trophic level is referred to as the biomass. Biomass can be considered as the weight of all living organisms within a particular ecosystem or at a specific trophic level. This includes animals, plants, microorganisms and all other living things. For example, in a forest ecosystem, the biomass includes everything from the massive trees to the tiny fungi and bacteria within the soil. Therefore, the answer to the student's question is d. biomass.
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What type of intermolecular forces exist between br2 and ccl4?
The intermolecular forces between Br2 and CCl4 are London dispersion forces, as both substances are nonpolar molecules.
Explanation:The intermolecular forces that exist between Br2 and CCl4 are London dispersion forces. These are the weakest type of intermolecular force and exist between all molecules, irrespective of whether they are polar or nonpolar. Br2 and CCl4 both are nonpolar molecules, so they don't exhibit dipole-dipole attractions, which are typically stronger than dispersion forces.
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What is the total pressure of a gaseous mixture that contains three gases with partial pressures of 0.845 atm, 120 torr and 210 mm hg? 972 torr 0.411 atm 331 torr 1175 torr?
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What is the product when Bismuth (symbol Bi, atomic number 83, and radioisotope with a mass number of 214) emits an alpha particle? Give name or symbol of new element, its atomic number, and its mass number for full credit. Show work.
Answer : The correct answer is Name = Thallium (Th) , atomic mass = 210 and atomic number = 81 .
Alpha decay :
When atomic nucleus emits an alpha particle that process is known as alpha particle decay . The symbol of alpha particle is [tex] _2^4He [/tex] , where 4 is atomic mass ( 2 protons + 2 neutrons ) and 2 atomic number .
When alpha particle is released the resultant nuclei (daughter nuclei) have 4 less atomic mass and 2 less atomic number .
Example for nuclear equation of alpha decay can be expressed as:
[tex] ^{230}_{90}Th \rightarrow _2^4He + ^{226}_{88}Ra [/tex]
Given :
Radioisotope = Bi Atomic mass = 214 Atomic number = 83
When it will release alpha particle , atomic mass will be decreased by 4 and atomic number by 2 .
Atomic mass = 214 - 4 = 210 Atomic number = 83-2 = 81
The atom with atomic number 81 is Thallium (Tl) . Hence the daughter nuclei so produced is [tex] ^{210}_{81}Tl [/tex]
The nuclear reaction can be written as :
[tex] ^{214}_{83}Tl \rightarrow ^4_2He + ^{210}_{81}Tl [/tex]