In the procedure, step 3(a) states that washing the precipitate is necessary. The reason for washing the precipitate with hot water is that it removes any remaining impurities and unreacted chemicals.
Washing the precipitate helps to purify it and remove unwanted particles. Hot water is used because it can dissolve impurities and wash them away more effectively than cold water. Additionally, the hot water can increase the rate of precipitation, making the process faster. If the precipitate is not washed properly, it can have a negative effect on the final product. The washing process ensures that the precipitate is pure and ready for further use. Overall, washing the precipitate is a crucial step in the procedure to ensure the purity and quality of the final product.
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Substances have a fixed arrangement of atoms. true or false (NO LINKS PLEASE)
Answer:
True
Explanation:
Our body is also a good conductor
of electricity because of the
presence of ______.
Please answer it this is my last question on my test i'll give you 20 points to answer?
According to the Standard Reduction Potential Table in your textbook, assign the anode and cathode for thecell pairs, B1-B2, A1-B2, AND A2-B2 described in the Procedure
For the B₁-B₂ cell pair, B₂ is the cathode, and B₁ is the anode. For the A₁-B₂ cell pair, B₂ is the cathode, and A₁ is the anode. For the A₂-B₂ cell pair, B₂ is the cathode, and A₂ is the anode.
B₁-B₂:
The half-reaction at B₁ is given as A⁺(aq) + 2e⁻ → A(s) with a reduction potential of -0.78 V.
The half-reaction at B₂ is given as B⁺(aq) + e⁻ → B(s) with a reduction potential of -0.45 V.
Since the reduction potential of B₂ (-0.45 V) is more positive than B₁ (-0.78 V), B2 will be the cathode, and B1 will be the anode.
A₁-B₂:
The half-reaction at A₁ is given as C⁺(aq) + 2e⁻ → C(s) with a reduction potential of -0.95 V.
The half-reaction at B₂ is the same as mentioned before B⁺(aq) + e⁻ → B(s) with a reduction potential of -0.45 V.
Since the reduction potential of B₂ (-0.45 V) is more positive than A₁ (-0.95 V), B₂ will be the cathode, and A₁ will be the anode.
A₂-B₂:
The half-reaction at A₂ is given as D⁺(aq) + 2e⁻ → D(s) with a reduction potential of -0.70 V.
The half-reaction at B₂ is the same as mentioned before B⁺(aq) + e⁻ → B(s) with a reduction potential of -0.45 V.
Since the reduction potential of B₂ (-0.45 V) is more positive than A₂ (-0.70 V), B₂ will be the cathode, and A₂ will be the anode.
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it takes 45 hours for a 6.00 mg sample of sodium-24 to decay to 0.750 mg. what is the half-life of sodium-24?
To find the half-life of sodium-24, we can use the formula for exponential decay:
N(t) = N₀ * (1/2)^(t / t₁/₂)
Where:
N(t) is the amount of the substance remaining at time t
N₀ is the initial amount of the substance
t is the time elapsed
t₁/₂ is the half-life of the substance
Given:
N₀ = 6.00 mg (initial amount)
N(t) = 0.750 mg (amount after 45 hours)
Plugging in these values, we can solve for t₁/₂:
0.750 mg = 6.00 mg * (1/2)^(45 / t₁/₂)
Dividing both sides of the equation by 6.00 mg:
(0.750 mg) / (6.00 mg) = (1/2)^(45 / t₁/₂)
0.125 = (1/2)^(45 / t₁/₂)
To eliminate the base of 1/2, we can take the logarithm of both sides:
log₂(0.125) = 45 / t₁/₂ * log₂(1/2)
Using the property log₂(a^b) = b * log₂(a):
log₂(0.125) = 45 * log₂(1/2) / t₁/₂
We know that log₂(1/2) = -1, so we can simplify the equation further:
log₂(0.125) = -45 / t₁/₂
Now, we can solve for t₁/₂:
t₁/₂ = -45 / log₂(0.125)
Using a calculator:
t₁/₂ ≈ -45 / (-3) ≈ 15
The half-life of sodium-24 is approximately 15 hours.
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Which of the following balances has the least uncertainty? (PSS.1)
Group of answer choices
platform balance, +/- 0.1 g
analytical balance, +/- 0.0001 g
All balances have the same uncertainty
triple-beam balance, +/- 0.01 g
electronic balance, +/- 0.001 g
if i have 340 ml of a 0.5 m nabr solution, what will the concentration be if i add 500 ml more water to it?
The final concentration of the solution is determined as 0.59 M.
What is the final concentration of the solution?The concentration of a solution or molarity of a solution is defined as the ratio of number of moles of solute to the liters of the solution.
Molarity, M = n / V
where;
n is the number of moles of the soluteV is the volume of the solutionThe final concentration of the solution is calculated as follows;
the number of moles = 0.5 m
the total volume after adding 500 ml of water = 340 ml + 500 ml = 840 ml = 0.84 L
Molarity = 0.5 m / 0.84 L
Molarity = 0.59 M
Thus, the final concentration of the solution is determined as 0.59 M.
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Given the balanced chemical equation: 2 H2 + O2 → 2 H20. Choose
the description below that most accurately describes the reaction.
O 2 moles of hydrogen react with 1 mole of oxygen to form 2 moles of water
O 2 moles of water react with 1 mole of hydrogen to form 2 moles of oxygen
O equal moles of hydrogen and oxygen react to form an equal amount of
water
O 4 moles of hydrogen react with 2 moles of oxygen to form 4 moles of water
Answer:
The answer is
2 moles of hydrogen react with 1 mole of oxygen to form 2 moles of water
Consider a particle in a one-dimensional box. a. For a box of length 1 nm, what is the probability of finding the particle within 0.01 nm of the center of the box for the lowest-energy level? b. Answer part (a) for the first excited state. c. The longest-wavelength transition for a particle in a box (not the box in part (a)] is 200 nm. What is the wavelength if the mass of the particle is doubled? What is the wavelength if the charge of the particle is doubled? What is the wavelength if the length of the box is doubled?
The transition wavelength, λ is given as:λ = (hc)/Eλ = (6.626 x 10^-34 Js * 3 x 10^8 m/s)/(4.585 x 10^-20 J)λ = 4.325 x 10^-7 mλ = 432.5 nmTherefore, if the length of the box is doubled, the transition wavelength remains the same as 200 nm.
The length of the box, L = 1 nm.The transition wavelength, λ = 200 nm.Formula:For particle in a one-dimensional box,For the energy of a particle in a one-dimensional box,E = (n²h²)/(8mL²)where, n = quantum numberh = Planck's constanm = mass of the particleL = length of the box.1. For the lowest energy level,n = 1E₁ = (n²h²)/(8mL²)E₁ = (1²h²)/(8mL²)E₁ = (1*6.626 x 10^-34 Js)²/(8(9.11 x 10^-31 kg)(1 x 10^-9 m)²)E₁ = 9.170 x 10^-20 JFrom the above formula, the probability of finding the particle within 0.01 nm of the center of the box is given as:ψ(x) = sqrt(2/L)sin(nπx/L)Probability, P = ∫ψ²dxFrom the above formula, the probability of finding the particle within 0.01 nm of the center of the box for the lowest-energy level is given as:P = ∫[sqrt(2/L)sin(πx/L)]²dxP = ∫2/L sin²(πx/L)dxP = 2/L * L/2P = 1Hence, the probability of finding the particle within 0.01 nm of the center of the box for the lowest-energy level is 1.2. For the first excited state,n = 2E₂ = (n²h²)/(8mL²)E₂ = (2²h²)/(8mL²)E₂ = (4*6.626 x 10^-34 Js)²/(8(9.11 x 10^-31 kg)(1 x 10^-9 m)²)E₂ = 3.668 x 10^-19 JFrom the above formula, the probability of finding the particle within 0.01 nm of the center of the box for the first excited state is given as:P = ∫[sqrt(2/L)sin(2πx/L)]²dxP = ∫2/L sin²(2πx/L)dxP = 2/L * L/2P = 0.5Hence, the probability of finding the particle within 0.01 nm of the center of the box for the first excited state is 0.5.3. (i) If the mass of the particle is doubled:For the energy of a particle in a one-dimensional box,E = (n²h²)/(8mL²)The energy of a particle is inversely proportional to the mass of the particle.Hence, if the mass of the particle is doubled, the energy of the particle is halved.E = 0.5E₁ = 0.5(9.170 x 10^-20 J)E = 4.585 x 10^-20 JFrom the above formula, the transition wavelength, λ is given as:λ = (hc)/Eλ = (6.626 x 10^-34 Js * 3 x 10^8 m/s)/(4.585 x 10^-20 J)λ = 4.325 x 10^-7 mλ = 432.5 nm(ii) If the charge of the particle is doubled:The charge of the particle does not have any effect on the energy of the particle.Therefore, the transition wavelength, λ remains the same as 200 nm.(iii) If the length of the box is doubled:For the energy of a particle in a one-dimensional box,E = (n²h²)/(8mL²)The energy of a particle is inversely proportional to the length of the box.Hence, if the length of the box is doubled, the energy of the particle is halved.E = 0.5E₁ = 0.5(9.170 x 10^-20 J)E = 4.585 x 10^-20 JFrom the above formula, the transition wavelength, λ is given as:λ = (hc)/Eλ = (6.626 x 10^-34 Js * 3 x 10^8 m/s)/(4.585 x 10^-20 J)λ = 4.325 x 10^-7 mλ = 432.5 nmTherefore, if the length of the box is doubled, the transition wavelength remains the same as 200 nm.
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calculate the temperature (in°c) at which pure water would boil at a pressure of 537.7 torr. hvap = 40.7 kj/mol
At a pressure of 537.7 torr, pure water would boil at approximately 95.8°C.
To calculate the boiling point of water at a given pressure, we can use the Clausius-Clapeyron equation:
ln(P2/P1) = (-ΔHvap/R) × (1/T2 - 1/T1)
where:
P1 and P2 are the initial and final pressures,
ΔHvap is the molar enthalpy of vaporization,
R is the ideal gas constant (8.314 J/(mol·K)),
T1 is the initial temperature,
T2 is the final temperature.
In this case, we want to find the boiling point (T2) of water at a pressure of 537.7 torr. The normal boiling point of water is 100°C (373.15 K) at atmospheric pressure (760 torr).
We can rearrange the equation to solve for T2:
T2 = (1/(((-ΔHvap/R) × (1/T1)) + (ln(P2/P1))))
Substituting the given values:
P1 = 760 torr
P2 = 537.7 torr
ΔHvap = 40.7 kJ/mol (convert to J/mol by multiplying by 1000)
R = 8.314 J/(mol·K)
T1 = 373.15 K
T2 = (1/(((-40.7 kJ/mol × 1000 J/kJ) / (8.314 J/(mol·K)) × (1/373.15 K)) + (ln(537.7 torr/760 torr))))
Calculating this expression gives us:
T2 ≈ 95.8°C
Therefore, at a pressure of 537.7 torr, pure water would boil at approximately 95.8°C.
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cbr4 has a higher vapor pressure at the same temperature than ccl4. T/F?
CBr₄ has a higher vapor pressure at the same temperature than CCl₄. The statement is False.
The vapor pressure of a liquid is the pressure exerted by the vapor of the liquid in equilibrium with the liquid. The vapor pressure of a liquid depends on the strength of the intermolecular forces in the liquid. The stronger the intermolecular forces, the lower the vapor pressure.
In the case of CCl₄ and CBr₄, the intermolecular forces are London dispersion forces. The size of the atom or molecule affects the strength of the London dispersion forces. The larger the atom or molecule, the stronger the London dispersion forces.
Bromine is larger than chlorine, so the intermolecular forces in CBr₄ are stronger than the intermolecular forces in CCl₄. Therefore, CCl₄ will have a higher vapor pressure than CBr₄ at the same temperature.
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Write the pressure equilibrium constant expression for this reaction. 2Li3N(s) -> 6 Li(s) + N2(g)
The pressure equilibrium constant expression for the given reaction 2Li3N(s) ⇌ 6Li(s) + N2(g) is given below: P = (PN2 ) (PLi)6/ (PLi3N )2Where, PN2 is the partial pressure of nitrogen PLi is the partial pressure of lithiumPLi3N is the partial pressure of lithium nitride.
The above formula of pressure equilibrium constant expression gives the ratio of the product of partial pressures of reactants and products to the power of their stoichiometric coefficients. Here, the stoichiometric coefficients of Li3N, Li and N2 are 2, 6 and 1 respectively. The reaction 2Li3N(s) ⇌ 6Li(s) + N2(g) represents the dissociation of lithium nitride to lithium and nitrogen gases. The dissociation reaction is endothermic.
As the temperature increases, the dissociation of lithium nitride increases which results in the formation of more lithium and nitrogen gas molecules. Therefore, the value of the equilibrium constant for this reaction increases with increasing temperature. The above-pressure equilibrium constant expression helps to determine the equilibrium concentration of reactants and products when the reaction is in equilibrium.
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Which of the following explanations accounts for the fact that the ion-solvent interaction is greater for Li+ than for K+?
The ionization energy of Li is higher than that for K.
Li has a lower density than K.
Li+ is of a lower mass than K+
Li+has a smaller ionic radius than K+
Li reacts with water more slowly than K.
The most appropriate explanation among the given options for the fact that the ion-solvent interaction is greater for Li⁺ than for K⁺ is that "Li⁺ has a smaller ionic radius than K⁺." Option D is correct.
Ionic radius refers to the size of an ion, specifically the distance between the nucleus and the outermost electron shell. Smaller ions tend to have stronger interactions with solvent molecules because the charge is more concentrated in a smaller space, leading to a higher electrostatic attraction between the ion and the surrounding solvent molecules.
In this case, Li⁺ has a smaller ionic radius compared to K⁺. As a result, Li⁺ has a stronger interaction with the solvent molecules, which leads to a greater ion-solvent interaction.
Hence, D. is the correct option.
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--The given question is incomplete, the complete question is
"Which of the following explanations accounts for the fact that the ion-solvent interaction is greater for Li⁺ than for K⁺? A) The ionization energy of Li is higher than that for K. B) Li has a lower density than K. C) Li⁺ is of a lower mass than K⁺ D) Li⁺ has a smaller ionic radius than K⁺ E) Li reacts with water more slowly than K."--
Can you think of something you do or a hobby you have that is physics
related? Explain your thinking as to how what you do is Physics related.
You can take physics as a hobby and also it is great that you like both maths and physics as well and also want to be an computer science engineer because physics and math
Shaun's doctor has recommended that he consume 200 calories of protein a day. Shaun consumed 176 calories of protein in one day. How much more protein does he need to consume to reach the required amount? (1 gram of protein = 4 calories)
Answer: Shaun must consume 6 more g of protein to reach the required amount.
Explanation:
Given : Recommended amount of protein = 200 calories
Now 4 calories = 1 gram of protein
Thus 200 calories = [tex]\frac{1}{4}\times 200=50[/tex] g of protein.
Calories consumed per day by Shaun = 176 calories
176 calories = [tex]\frac{1}{4}\times 176=44[/tex] g of protein.
Thus Shaun need to consume = (50-44) g = 6 of protein to reach the required amount.
Shaun must consume 6 more g of protein to reach the required amount.
Which of the following is a FALSE statement? *
A. Heat moves through solids by by conduction.
B. Molecules move faster in warmer substances.
C. Warm water is denser than cold water.
D. Heat moves through liquids and gases by convection.
Answer:
C: Warm water is denser than cold water
4. Identify What do scientists call a substance that forms during a chemical reaction?
5. Identify On what side of the equation are reactants found?
Answer:
4. Reactant
5. Left
I hope this helps ❤️❤️
Mass = 22g Volume = 2cm3 What is the Density?
Answer:
11g/cm^3
Explanation:
The density of a substance can be found By
density= Mass/volume
From the question
mass = 22 g
volume = 2 cm³
22/2=11
We have the final answer as
11 g/cm³
Answer:
11g/cm^3
Explanation:
It is because the constant formula density is
Density=Mass/ Volume.
Therefore we have
Density=22g/2cm^3
Which is = 11g/cm^3
What is the process of old crust sinking back into a mantle?
Use the following words to fill in the text (can be used more than once).
Anode,Anode to cathode,Battery,Cathode,Chemical to electrical,Electrical to chemical,Electrolysis,Electroplating,Endothermic,Exothermic,N/A
Negative,No,Non-Spontaneous,Oxidation,Positive,Reduction,Spontaneous,Yes.
Answer:
VOLTIC CELL
Battery
Electrical to chemical
Endothermic
Electrolysis
Chemical to electrical
Anode
Anode to cathode
Battery
Endothermic
Negative
Enthomeric
Reduction
Oxidation
ELECTRYOTIC CELL
No
Non spontaneous
positive
negative
yes
Anode
Electrical to chemical
Anode to cathode
Exothermic
positive
oxidation
Electroplating
Chemical to electrical
To remove a tight-fitting lid from a jar, Megan runs the lid under hot water.
What happens to the Jar lid when its temperature increases?
A.The temperature increases, and the lid expands
B.The temperature decreases, and the lid contracts.
C.The potential energy increases, and the lid contracts.
D.The potential energy decreases, and the lid expands
Answer:
A
Explanation:
How many gram of ice at 0C can be melted by the condensation of 12.39g of steam at 100C, assuming a complete transfer of thermal energy?
The mass of the ice melted by a complete transfer of thermal energy is 83.84 g.
What is the mass of the ice melted?The mass of the ice melted by a complete transfer of thermal energy is calculated by applying the following equation as follows;
Q = mcΔθ
where;
m is the massc is the specific heat of waterΔθ is change in temperatureheat gained by the ice = heat loss by the steam
The mass of the ice melted by a complete transfer of thermal energy is calculated;
m x heat of fusion = 12.39g x heat of vaporization
m x 334 J/g = 12.39 g x 2260 J/g
334m = 28,001.4
m = 28,001.4 / 334
m = 83.84 g
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In a food chain, energy does NOT flow directly from - F producer to decomposer G producer to consumer H consumer to decomposer J consumer to producer
Answer:
producer to decomposer
Explanation:
This is because in a food chain , energy flow from one trophic level to another. The producer which include plants are the source of energy which they manufacture good in the presence of light energy from sun. Energy flow directly from the producer to the primary consumer which are heterotrophs that feed on plants. Energy flow from consumer to decomposer after the consumer died and it is decayed.
What is a net ionic equation? A. An equation that shows only those particles involved in the reaction, and that is balanced for mass but not for charge B. An equation that shows only those particles involved in the reaction, and that is balanced for both mass and charge C. An equation that describes the flow of oxygen in a combustion reaction D. An equation that shows the cations as reactants and the anions as products
Answer:
B. An equation that shows only those particles involved in the reaction, and that is balanced for both mass and charge
Explanation:
A net ionic equation is a chemical equation that will only show the elements, compounds, and ions that are directly involved in the chemical reaction. It comes from the balanced molecular equation and should be balanced by both mass and charge.
What makes sound waves different from light waves?
Answer:
Light waves are electromagnetic waves while sound waves are mechanical waves. light waves are transverse while sound waves are longitudinal. sound waves require a material medium to travel, and hence, cannot travel in a vacuum. the speed of light in a medium is constant.
Explanation:
Hope this helped Mark BRAINLIEST!!
Newton's third law of motion is summarized as the law of action-reaction. For every action, there is an equal but opposite reaction. Which example best illustrates the application of Newton's law of action-reaction? Choose all that apply.
Answer:
When we stand on the floor, we apply a force on the floor surface in the downward direction and in return the floor also exerts an upward and equal force on us.
Explanation:
Newton' third law is vey famous and it states that for each and every action, there applies an equal but opposite reaction. Thus the action force and the reaction force always acts on pairs. But they does not contribute to the motion of the object.
One such example that illustrates the action and reaction force from Newton's law is when we stand on the floor we exert a force on the floor surface in downward direction. The floor surface also exerts an opposite and equal force on us in the upward direction.
Calculate the number of moles in 7.04 g of lead (II) nitrate, Pb(NO3)2
Can Someone help me covert this?!
Answer:
moles Pb(NO₃)₂ ≅ 0.0213 mole (three sig. figs.)
Explanation:
converting...
grams to moles => divide by formula weight
moles to grams => multiply by formula weight
for this problem ...
moles Pb(NO₃)₂ = 7.04g / 331.2g/mol = 0.021256 (calculator answer)
≅ 0.0213 mole (three sig. figs.)
Mole measure the number of elementary entities of a given substance that are present in a given sample. Therefore, the number of moles in 7.04 g of lead (II) nitrate, Pb(NO₃)₂ is 0.0212moles.
What is mole?The SI unit of amount of substance in chemistry is mole. The mole is used to measure the quantity or amount of substance. We know one mole of any element contains 6.022×10²³ atoms which is also called Avogadro number.
Mathematically,
mole =given mass ÷ molar mass
Molar mass of 1 mole of Pb(NO₃)₂ = 331.2g/mol
given mass of Pb(NO₃)₂=7.04g
Substituting the values in above formula we get
moles of Pb(NO₃)₂ = 7.04g / 331.2g/mol
moles of Pb(NO₃)₂ = 0.0212moles
Therefore, the number of moles in 7.04 g of lead (II) nitrate, Pb(NO₃)₂ is 0.0212moles.
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Question 4 (2 points)
Manganese-56 decays by beta emission and has a half life of 2.6 hours. If a sample
is analyzed and found to contain 6.25% parent isotopes and 93.75% daughter
isotopes, what must the age of the sample be?
Answer:
10.4 hours
Explanation:
Now from;
0.693/t1/2 = 2.303/t log (No/N)
t1/2= half life of the radioactive isotope
t = age of the radioactive isotope
No= Original amount of radioactive isotope
N= amount of radioactive isotope left after time t
Substituting values;
N = 0.0625No
0.693/2.6 = 2.303/t log (No/0.0625No)
0.693/2.6 = 2.303/t log (1/0.0625)
0.267 = 2.303/t * log 16
0.267 = 2.773/t
t = 2.773/0.267
t = 10.4 hours
Calculate the mass in grams of 3.6 mol of iron(II) hydroxide.
Hydrogen peroxide and water both contain the same two elements. Write their chemical formulas. Compare and contrast their properties. Explain the importance of writing correct chemical formulas
Hydrogen peroxide and water both contain the same two elements. The chemical formulas of hydrogen peroxide and water are respectively H2O2 and H2O. The two compounds have distinct physical and chemical properties. Here is a long answer to the question posed.
Water is a colorless, odorless, and tasteless liquid that is vital for life. Its melting point is 0 degrees Celsius, while its boiling point is 100 degrees Celsius. Water is the most prevalent chemical substance on Earth, with about 71% of the planet's surface covered by it.
Hydrogen peroxide is a pale blue liquid that is slightly more viscous than water. It has a bitter taste, and its odor is similar to that of bleach. The boiling point of hydrogen peroxide is 150.2°C, while the melting point is -0.43°C. Hydrogen peroxide is a powerful oxidizer that is commonly used as a bleaching agent, disinfectant, and antiseptic.
Chemical formulas are utilized in a variety of scientific applications, including chemical reactions and product descriptions. An incorrect chemical formula can have significant ramifications, potentially resulting in the formation of a hazardous substance.
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Use the food web below to answer the following
question.
Frog
Red fox
Grasshopper
Weasel
Goldfinch
Great horned om
Clover
Deer mouse
Which group is not represerted in the food web?
A. producers
B. primary consumers
C. secondary consumers
D. decomposers
Answer:
uhm i believe its D hope i helped
Explanation:
Answer:
D. decomposers