Explanation:
Relation between freezing temperature and molal concentration is as follows.
[tex]\Delta T_{f} = k_{f} \times m[/tex]
The given data is as follows.
[tex]\Delta T_{f}[/tex] = difference in temperature = [tex][0 - (-2.75)]^{o}C[/tex] = [tex]2.75^{o}C[/tex]
[tex]k_{f} = 1.86^{o}C/mol[/tex]
molality, (m) = ?
Now, putting the given values into the above formula as follows.
m = [tex]\frac{\Delta T_{f}}{k_{f}}[/tex]
= [tex]\frac{2.75^{o}C}{1.86^{o}C/mol}[/tex]
= 1.48 m
Therefore, we can conclude that molal concentration of glucose in the given solution is 1.48 m.
The half-life for the radioactive decay of c-14 is 5730 years and is independent of the initial concentration. how long does it take for 25% of the c-14 atoms in a sample of c-14 to decay? if a sample of c-14 initially contains 1.5 mmol of c-14, how many millimoles are left after 2255 years?
Answer :
(1) The time passed by the sample is [tex]2.4\times 10^3\text{ years}[/tex]
(2) The amount left after decay process is 1.14 mmol.
Explanation :
Part 1 :
Half-life = 5730 years
First we have to calculate the rate constant, we use the formula :
[tex]k=\frac{0.693}{t_{1/2}}[/tex]
[tex]k=\frac{0.693}{5730\text{ years}}[/tex]
[tex]k=1.21\times 10^{-4}\text{ years}^{-1}[/tex]
Now we have to calculate the time passed.
Expression for rate law for first order kinetics is given by:
[tex]t=\frac{2.303}{k}\log\frac{a}{a-x}[/tex]
where,
k = rate constant = [tex]1.21\times 10^{-4}\text{ years}^{-1}[/tex]
t = time passed by the sample = ?
a = let initial amount of the reactant = 100 g
a - x = amount left after decay process = 100 - 25 = 75 g
Now put all the given values in above equation, we get
[tex]t=\frac{2.303}{1.21\times 10^{-4}}\log\frac{100}{75}[/tex]
[tex]t=2377.9\text{ years}=2.4\times 10^3\text{ years}[/tex]
Therefore, the time passed by the sample is [tex]2.4\times 10^3\text{ years}[/tex]
Part 2 :
Now we have to calculate the amount left.
Expression for rate law for first order kinetics is given by:
[tex]t=\frac{2.303}{k}\log\frac{a}{a-x}[/tex]
where,
k = rate constant = [tex]1.21\times 10^{-4}\text{ years}^{-1}[/tex]
t = time passed by the sample = 2255 years
a = let initial amount of the reactant = 1.5 mmol
a - x = amount left after decay process = ?
Now put all the given values in above equation, we get
[tex]2255=\frac{2.303}{1.21\times 10^{-4}}\log\frac{1.5}{a-x}[/tex]
[tex]a-x=1.14mmol[/tex]
Therefore, the amount left after decay process is 1.14 mmol.
Which is the strongest type of intermolecular force between solute and solvent in br2(l) in ccl4(l)?
The strongest intermolecular force between bromine (Br2) and carbon tetrachloride (CCl4) when Br2 is dissolved in CCl4 is the London dispersion force, as both compounds are nonpolar.
Explanation:The strongest type of intermolecular force between solute and solvent in a mixture of Br2(l) dissolved in CCl4(l) is likely the London dispersion force. Both Br2 and CCl4 are nonpolar molecules, which means they lack a permanent dipole moment. Consequently, they do not exhibit dipole-dipole interactions. However, due to the temporary fluctuations in electron density within these molecules, instantaneous dipoles can be induced, giving rise to London dispersion forces, which are the only significant intermolecular force between the two substances.
Generally, London dispersion forces increase with the size and number of electrons in the molecule, leading to greater interactions. Bromine (Br2) and carbon tetrachloride (CCl4) both have a relatively large number of electrons and molecular masses, thus contributing to the strength of their dispersion forces.
Learn more about Intermolecular Forces here:https://brainly.com/question/34620632
#SPJ6
Calculate the residence time of sodium. Fill in the blanks.
Use T= m/f
Mass (m) Flow rate (f)
ton ton/year
Sodium 2.8 X 10^13 3.5 X 10^5
Zach is investigating the residence time of sodium in sea water. According to Zach's data table, the residence time of sodium written in scientific notation is _____________ X 10 _________ years.
Answer: 8 x 10^7
Explanation:
Neutralization is an important prart of digestion. Why?
How many molecules of sulfur trioxide are present in 1.87 moles of this compound?
During the process of transpiration, water _______ a plant through the _______.
A. enters; stomata
B. exits; stomata
C. exits; chloroplasts
D. enters; chloroplasts
Why do you heat the empty crucible?
The compound p4s3 is oxidized by nitrate ions in acid solution to give phosphoric acid, sulfate ions, and nitric oxide no. what is the coefficient of h3po4 in the balanced equation for the reaction?
which state removed a physician's license to practice medicine.
Money management becomes more important when you are responsible for paying all your own expenses.
Answer:
True
Explanation:
When you are responsible for paying your own expenses, you start to take more responsibility for how your money will be spent. At this point you begin to understand the importance and begin to value money management. Money management is the activity, where you decide how much of the money you have will be spent and what will be spent. When you pay your own expenses, you must manage your money well and ensure that all your needs, such as home, food, taxes, gasoline and other things are paid. If you do not manage your money you will end up spending on needless things and you may have some unpaid necessary expenses, which will cause problems for your life.
The property that describes the ease with which an atom gives up an electron to form a positive ion
Ionization energy is the property of an atom that describes the ease with which an atom gives up an electron to form a positive ion.
What is ionization energy?
The ionization energy of a chemical element is expressed in joules or electron volts. It is commonly measured inside an electric discharge tube where fast-moving electrons are generated due to an electric current collision with a gaseous atom of the element.
This causes the ejection of one of its electrons. In the case of a hydrogen atom, which has only one orbiting electron which is in turn bound to a nucleus with only one proton, the ionization energy of 2.18 × 10^−18 joule or 13.6 electron volts is needed to move the electron from its lowest energy level out of the atom.
The ionization energy magnitude is dependent on the element and the combined effects of the electric charge of its nucleus, atomic size, and also its electronic configuration. Electron removal is also the hardest for noble gases and easiest for alkali metals.
The ionization energy required for the removal of electron removal is the hardest as the electron number decreases progressively. Because as the atom loses electrons, the positive charge on the nucleus of the atom does not change; thus, as each electron is removed, the remaining ones are held more firmly.
Therefore, Ionisation energy is the property of an atom that describes the ease with which an atom gives up an electron to form a positive ion.
Read more about ionization energy, here
https://brainly.com/question/27356170
#SPJ6
why is mercury the only metal to have been used in thermometers
Mercury is liquid at room temperature, expands consistently, and doesn't wet glass, making it ideal for accurate temperature measurements in thermometers despite its toxicity.
Mercury is the only metal to have been used extensively in thermometers for several reasons. Firstly, it is the only metal that is liquid at room temperature, allowing it to easily expand and contract with temperature changes, making it excellent for precise temperature measurements. Additionally, mercury has a high coefficient of expansion, meaning it expands and contracts uniformly, resulting in accurate and consistent readings.
Mercury also does not wet glass, maintaining a clear meniscus that makes it easy to read the temperature. Its high density compared to other liquids, such as water, allows for more compact and portable thermometers. Despite its hazardous nature, these unique physical properties have historically made mercury the preferred choice for use in thermometers until safety concerns led to the adoption of safer alternatives like alcohol-filled instruments.
Calculate the volume in ml of 0.20m naoh needed to react completely with 100.ml of 0.040m acetic acid.
A solution of naoh(aq) contains 6.6 g of naoh(s) per 100.0 ml of solution. calculate the ph and the poh of the solution at 25 °c.
The pH and pOH of 6.6g of NaOH in 100mL solution are -0.217 and 14.217 respectively
Data;
Volume = 100.0mLmass of NaOH = 6.6gmolarity of NaOH = ?Molarity of the SolutionTo find the pOH and pH of this solution, we have to know the molarity of this solution.
Molarity = number of moles of solute / volume of the solution
number of moles of the solute = mass / molar mass
molar mass of NaOH = 40g/mol
number of moles = 6.6/40 = 0.165moles
Molarity of this solution is
[tex]M = \frac{number of moles }{volume of solution}\\M = \frac{0.165}{0.1}\\ Molarity = 1.65M[/tex]
pOH of the Solution[tex]pOH= -log[OH^-]\\pOH = -log[1.65]\\pOH = -0.217[/tex]
At 25°C, the pOH of NaOH is -0.217, let's calculate the pH
[tex]pOH+pH=14\\-0.217+pH=14\\pH=14-(-0.217)\\pH=14.217[/tex]
From the calculations above, the pH and pOH of 6.6g of NaOH in 100mL solution are -0.217 and 14.217 respectively.
Learn more on molarity, pH and pOH of a solution here;
https://brainly.com/question/13557815
https://brainly.com/question/13423425
The number of moles of NaOH in the solution is 0.165 mol and its molarity is 1.65 M. The pOH of the solution is -0.217 and the pH is 14.217.
Explanation:The mass of Sodium Hydroxide present in the solution is 6.6 g. The molar mass of Sodium Hydroxide (NaOH) is approximately 40 g/mol. Therefore, the number of moles present in the solution can be calculated by dividing the mass by the molar mass. So, the number of moles = 6.6/40 = 0.165 mol.
The volume of the solution is 100 ml or 0.1 L. The molarity of the solution can be found by dividing the number of moles by the volume in liters which gives us, Molarity = 0.165/0.1 = 1.65 M.
Because NaOH is a strong base, in water it dissociates completely to form hydroxide ions (OH-). Hence, the molarity of OH- is the same as the molarity of NaOH i.e., 1.65 M. In order to find the pOH we can use the formula -log[OH-], hence the pOH= -log(1.65) = -0.217.
The relationship between pH and pOH at 25 °C is given by the expression, pH + pOH = 14. Therefore, the pH can be calculated as follows, pH = 14 - pOH = 14 - (-0.217) = 14.217.
Learn more about pH calculation here:https://brainly.com/question/36153729
#SPJ3
Discuss how forests act as carbon sinks.
Answer:
They undergo photosynthesis which makes the carbon dioxide to be used rather than produced.
Explanation:
Hello,
Forests are widely known as the "Earth's lungs" due to the photosynthesis that vegetable life constantly perform as the carbon dioxide that is in the environment is used by them to produce energy, glucose and oxygen considering such metabolic pathway. Now, forest act as carbon sinks as the proportion between carbon dioxide consumers to producers is by far greater than 1 as long as there are more plants that use higher amounts of carbon dioxide than those that are released during the respiration of animals or any other natural process producing carbon dioxide.
Best regards.
When heat is removed from a substance, describe how the molecules are affected, what are causing these changes, describe what's happening in whole, and does the temp. increase or decrease?
Complete and balance the molecular equation, including phases, for the reaction of aqueous copper(II) chloride, CuCl2, and aqueous potassium phosphate, K3PO4.
Answer: The molecular equation is written below.
Explanation:
Every balanced chemical equation follows law of conservation of mass.
Law of conservation of mass states that mass can neither be created nor be destroyed but it can only be transformed from one form to another form.
This also means that total mass on the reactant side must be equal to the total mass on the product side.
A molecular equation is the balanced chemical equation where the ionic compounds are expressed as molecules rather than constituent ions.
The chemical equation for the reaction of copper (II) chloride and potassium phosphate follows:
[tex]3CuCl_2(aq.)+2K_3PO_4(aq.)\rightarrow Cu_3(PO_4)_2(s)+6KCl[/tex]
By Stoichiometry of the reaction:
3 moles of copper (II) chloride reacts with 2 moles of potassium phosphate to produce 1 mole of copper (II) phosphate and 6 moles of potassium chloride.
Hence, the molecular equation is written above.
Calculate the number of grams of Fe2O3 needed to react with 19.0 g C.
To calculate mass of Fe₂O₃ we need to apply concept of stoichiometry. So according to this we need molar mass of Fe₂O₃, mole ratio of Fe₂O₃ to C. Therefore the mass of Fe₂O₃ required to react with 19.0 g C is 67.4g.
What is stoichiometry?Stoichiometry is a part of chemistry that help us in making relationship between reactant and product from quantitative aspects.
The balanced equation is
2Fe₂O₃+3C [tex]\rightarrow[/tex] 3CO₂+4Fe
The molar ratio of Fe₂O₃ to carbon is 2:3
2 moles of Fe₂O₃ needed to react with 3 moles of carbon
3 mole of carbon needed= 2 mole of Fe₂O₃
1 mole of carbon needed = 2÷3 mole of Fe₂O₃
(19÷12) = 1.58 mole of carbon needed= (2÷3 )× 1.58 mole= 0.422 mole of Fe₂O₃
mass of Fe₂O₃ = moles of Fe₂O₃ ×Molar mass of Fe₂O₃
= 0.422 mole×159.70
= 67.4g
Therefore the mass of Fe₂O₃ required to react with 19.0 g C is 67.4g
To learn more about stoichiometry, here:
https://brainly.com/question/28780091
#SPJ5
To convert the moles of Fe₂O₃ to grams using its molar mass.
Explanation:To calculate the number of grams of Fe₂O₃ needed to react with 19.0 g C, we need to use the stoichiometric mole ratio from the balanced chemical equation. First, convert the given mass of C to moles using its molar mass. Then, use the mole ratio from the equation Fe₂O₃+ 3CO -> 2Fe + 3CO₂ to determine the moles of Fe₂O₃ needed. Finally, convert the moles of Fe₂O₃ to grams using its molar mass.
Given: 19.0 g C
Calculate: grams of Fe₂O₃
Therefore, 83.8 grams of Fe₂O₃ are needed to react with 19.0 grams of C.
If a solution containing 18.0 g of a substance reacts by first-order kinetics, how many grams remain after three half-lives?
2) So, after every period of one half-life the concentration of the reactant will decrease by half.
Based on the number of half-lives undergone by the substance, the mass of the substance remaining after three half-lives is 2.25 g.
What is half-life of a substance?The half-life of a substance is the time it will take for half the amount of the substance to decay or decompose.
The initial mass of the substance is 18.0 g
The substance undergoes three half-lives.
After the first half-life, mass remaining = 18/2 = 9.0 g
After the first half-life, mass remaining = 18/2 = 9.0 g
After the third half-life, mass remaining = 4.5/2 = 2.25 g
Therefore, the mass of the substance remaining after three half-lives is 2.25 g.
Learn more about half-life at: https://brainly.com/question/2320811
How many molecules of o2 are contained in a gas tank that contains 650. g of oxygen?
If 1495 J of heat is needed to raise the temperature of a 337 g sample of a metal from 55.0°C to 66.0°C, what is the specific heat capacity of the metal?
The specific heat capacity of the metal is calculated using the formula q=mcΔT. With the provided information (1495 J of heat, 337 g of metal, temperature change from 55.0°C to 66.0°C), the specific heat capacity is found to be 0.399 J/g°C.
Explanation:To calculate the specific heat capacity of the metal, we can use the formula q = mcΔT, where q is the heat absorbed or released (in joules), m is the mass of the substance (in grams), c is the specific heat capacity (in J/g°C), and ΔT is the change in temperature (in °C).
Given that 1495 J of heat is needed to raise the temperature of a 337 g sample of a metal from 55.0°C to 66.0°C, we have:
ΔT = 66.0°C - 55.0°C = 11.0°C
q = 1495 J
m = 337 g
Plugging these values into the formula, we can solve for c:
1495 J = (337 g)(c)(11.0°C)
c = 1495 J / (337 g × 11.0°C)
c = 0.399 J/g°C
Thus, the specific heat capacity of the metal is 0.399 J/g°C.
Which term is best defined as heat transfer that occurs when warm particles move in currents? A. evaporation B. convection C. conduction D. radiation
What is the ph of a sodium acetate (nac2h3o2) solution prepared by adding 0.820 grams of sodium acetate to 100.0 ml of water at 25.0 °c? the ka at 25.0 °c for acetic acid is 1.8 ⋅ 10-5?
The pH of a sodium acetate (NaC2H3O2) solution can be calculated using the equilibrium expression for the base hydrolysis reaction of the acetate ion.
Explanation:The pH of a sodium acetate (NaC2H3O2) solution can be calculated using the equilibrium expression for the base hydrolysis reaction of the acetate ion:
CH3CO2⁻ + H2O ⇌ CH3CO2H + OH⁻
This reaction is the reverse of the ionization reaction for acetic acid. The Kb value for the acetate ion is calculated as Kw/Ka, where Ka is the acid dissociation constant for acetic acid, given as 1.8 × 10⁻⁵ at 25.0 °C. To find the pH, we need to calculate the concentration of hydroxide ions (OH⁻) in the solution.
The hydroxide ion concentration can be calculated using the equation [OH⁻] = √(Kb × [CH3CO2H]). Given that the concentration of acetate ion [CH3CO2⁻] is equal to the initial concentration of sodium acetate, and assuming complete dissociation of sodium acetate in water, the concentration of acetic acid [CH3CO2H] will be equal to the initial concentration of sodium acetate. Therefore, [OH⁻] = √(Kb × [NaC2H3O2]). Finally, the pH of the solution can be calculated as -log[OH⁻].
Learn more about the pH of a sodium acetate solution here:https://brainly.com/question/32252831
#SPJ6
Which statements correctly compare mitosis and meiosis?
A)The result of mitosis is two identical diploid cells. The result of meiosis is four genetically different haploid cells.
B)Mitosis brings genetic variety to a species. Meiosis helps the body grow and heal.
C)Mitosis involves two cycles of cell division. Meiosis involves one cycle of cell division.
D) Cells that divide by mitosis carry the genetic information for body cells. Cells that divide by meiosis provide only the code for gender.
NEED ASAP
The statement comparing mitosis and meiosis accurately indicates that mitosis results in two identical diploid cells, whereas meiosis produces four genetically distinct haploid cells.
The correct statement that compares mitosis and meiosis is:
A) The result of mitosis is two identical diploid cells. The result of meiosis is four genetically different haploid cells.
Both processes are preceded by one round of DNA replication. However, while mitosis includes one cellular division resulting in two identical diploid cells, meiosis includes two nuclear divisions which result in four genetically distinct haploid cells. Mitosis is essential for growth and repair, and meiosis provides genetic diversity through sexual reproduction.
An 18 liter container holds 16.00 grams of oxygen gas (o2 at 45 °c. what is the pressure in the container?
How many grams of AgNO3 are needed to prepare a 0.25 m solution in 500 grams of water?
Question options:
125 g
0.125g
21.25 g
170g
Consider an amphoteric hydroxide, m(oh)2(s), where m is a generic metal. estimate the solubility of m(oh)2 in a solution buffered at ph
The solubility of an amphoteric hydroxide in a buffered solution depends on the pH of the solution. It can act as both an acid and a base. The Henderson-Hasselbalch equation can be used to estimate the solubility in a buffered solution.
Explanation:The solubility of an amphoteric hydroxide, M(OH)2, in a buffered solution depends on the pH of the solution. An amphoteric hydroxide can act as both an acid and a base. At low pH, the hydroxide ion concentration is low and the hydroxide ion reacts with the excess hydronium ions, reducing the solubility. At high pH, the hydronium ion concentration is low and the hydroxide ion concentration is high, increasing the solubility. In a buffered solution, the pH remains relatively constant due to the presence of a weak acid and its conjugate base. The solubility of the hydroxide in the buffered solution can be estimated using the Henderson-Hasselbalch equation.
Learn more about Solubility of amphoteric hydroxide in buffered solutions here:https://brainly.com/question/35354580
#SPJ3
In aqueous solution, classify these compounds as strong acids, weak acids, strong bases, or weak bases. ba(oh)2
A detailed description of what Alexander Fleming was famous for?
If 1.00 g of an unknown molecular compound contains 8.35 1021 molecules, what is its molar mass?