Answers
This question is asking for a method for the determination of the freezing point in a solution that does not have a noticeable transition in the cooling curve, which is basically based on a linear fit method.
The first step, would be to understand that when the transition is well-defined as the one on the attached file, we can just identify the temperature by just reading the value on the graph, at the time the slope has a pronounced change. For instance, on the attached, the transition occurs after about 43 seconds and the freezing point will be about 4 °C.
However, when we cannot identify a pronounced change in the slope, it will be necessary to use a linear fit method (such as minimum squares) to figure out the equation for each segmented line having a significantly different slope and then equal them so that we can numerically solve for the intercept.
As an example, imagine two of the segmented lines have the following equations after applying the linear fit method:
[tex]y=-3.5 x + 25\\\\y=-0.52 x + 2[/tex]
First of all, we equal them to find the x-value, in this case the time at which the freezing point takes place:
[tex]-3.5 x + 25=-0.52 x + 2\\\\-3.5 x+0.52 x =2-25\\\\x=\frac{-23}{-2.98}=7.72[/tex]
Next, we plug it in in any of the trendlines to obtain the freezing point as the y-value:
[tex]y=-3.5 (7.72) + 25\\\\y = 1.84[/tex]
This means the freezing point takes place after 7.72 second of cooling and is about 1.84 °C. Now you can replicate it for any not well-defined cooling curve.
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Related Questions
Which spheres include the water cycle? (Select all that apply.)
biosphere
geosphere
hydrosphere
atmosphere
Answers
Answer:
A, B, C, D
Explanation:
The water cycle is included in the atmosphere (water vapor in the air), the geosphere (water collection), the hydrosphere (water on earth: lakes, oceans, rivers), and the biosphere (where water interacts with all living things).
In an ecosystem, the water cycle is included in all the spheres that is biosphere,geosphere,hydrosphere and atmosphere.
What is an ecosystem?Ecosystem is defined as a system which consists of all living organisms and the physical components with which the living beings interact. The abiotic and biotic components are linked to each other through nutrient cycles and flow of energy.
Energy enters the system through the process of photosynthesis .Animals play an important role in transfer of energy as they feed on each other.As a result of this transfer of matter and energy takes place through the system .Living organisms also influence the quantity of biomass present.By decomposition of dead plants and animals by microbes nutrients are released back in to the soil.
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A chemical property is a change in _____.
density
physical state
hardness
composition of matter
Answers
Answer:
composition of an element
Which sentence best describes what happens during a change of state from
a solid to a liquid?
A. The temperature stays the same and the particle speed increases.
B. The temperature stays the same and the particle speed stays
constant
C. The temperature increases and the particle speed stays constant.
D. The temperature decreases and the particle speed decreases.
SUBMIT
Answers
Answer:
B
Explanation:
as temperature rises, the particles gain kinetic energy (they will move faster) so if temperatures stays constant, so will the movement or vibration of the particles
2. Alex pulls on the handle of a claw hammer with a force of 15 N. If
the hammer has a mechanical advantage of 5.2, how much force
is exerted on the nail in the claw?
Answers
Answer:
78n
Explanation:
The output force exerted on the nail in the claw is equal to 78 N which has a mechanical advantage of 5.2.
What is the mechanical advantage?The mechanical advantage can be demonstrated as the ratio of the output force to the Input force. The mechanical advantage of any machine can be expressed in the form of the ratio of the forces utilized to do the work.
The ratio of the resistance to the effort is said to be the actual mechanical advantage which will be less. The efficiency of a machine can be evaluated by equating the ratio of the output to its input.
Given, the input force = 15 N
The mechanical advantage of the hammer = 5.2
Mechanical advantage = Output force/ Input force
5.2 = Output/15
Output force = 15 ×5.2 = 78 N
Therefore, the force is exerted on the nail in the claw is equal to 78 N.
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What is the net charge of C
Answers
Explanation:
Sorry, I don't know, but I can tell you that when an atom, or a body, has the same amount of positive charges (protons) and negative charges (electrons), it is said to be electrically neutral. ... The net charge corresponds to the algebraic sum of all the charges that a body possesses.
Answer: Neutral carbon-12 (or any carbon atom) has 6 electrons with a total negative charge of 6e- orbiting a nucleus with a total positive charge of 6e+, so that the total net charge is zero. The nucleus is made up of 6 protons, each with a positive charge of e+, and 6 neutrons, each with zero charge.
Explanation:
Calculate the moles of HCl in 15 mL of a 0.50 M solution.
Answers
Explanation:
[tex]\tiny\implies Molarity = \dfrac{no. \: of \: moles \: of \: solute \times 1000}{volume \: of \: the \: solution \: (in \: ml)} [/tex]
[tex]\tiny\implies 0.50 = \dfrac{no. \: of \: moles \: of \: solute \times 1000}{15}[/tex]
[tex]\tiny\implies no. \: of \: moles \: of \: solute \times 1000 = 0.50 \times 15[/tex]
[tex]\tiny\implies no. \: of \: moles \: of \: solute \times 1000 = 7.5[/tex]
[tex]\tiny\implies no. \: of \: moles \: of \: solute = \dfrac{7.5}{1000} [/tex]
[tex]\tiny\implies \bf no. \: of \: moles \: of \: solute = 0.075 \: mol[/tex]
According to the electron configuration, which atom will be the most reactive?
1s^2 2s^2
1s^2 2s^2 2p^6 3s^2
1s^2 2s^2 2p^6 3s^2 3p^6
1s^2 2s^2 2p^6 3s^2 3p^6 4s^2
Answers
Answer:
The fourth atom.
Explanation:
Number of valence electrons in each of the four atoms:
First atom: two ([tex]2\, s^{2}[/tex].)Second atom: two ([tex]3\, s^{2}[/tex].)Third atom: eight ([tex]3\, s^{2}\; 3\, p^{6}[/tex].)Fourth atom: two ([tex]4\, s^{2}[/tex].)Without referring to a periodic table, the first, second, and fourth atoms would all belong to the alkali-earth metal elements. The third atom would belong to a noble gas element. (The four choices are beryllium, magnesium, argon, and calcium, respectively.)
Noble gas elements are highly stable. Thus, the third atom (argon) would be the least reactive among all four choices.
On the other hand, alkali-earth metals are reactive since they tend to lose their valence electrons. The reactivity of an alkali-earth atom depends on its ionization energy (the energy required to take a valence electron away from the atom.)
Since these atoms are in the same group, ionization energy would be smaller for atoms with a larger radius. In a given group, atoms with more filled electron shells would have a larger radius.
The first atom has two filled main shells, the second has three, whereas the fourth has four.
Thus, among the three alkali-earth metals in the choices:
[tex]\begin{aligned}&\text{Number of filled electron shells:} \\ & a < b < d\end{aligned}[/tex].
[tex]\begin{aligned}&\text{Atomic radius:} \\ & a < b < d\end{aligned}[/tex].
[tex]\begin{aligned}&\text{Ionization energy:} \\ & a > b > d\end{aligned}[/tex].
[tex]\begin{aligned}&\text{Reactivity:} \\ & a < b < d\end{aligned}[/tex].
The third choice (a noble gas) is the least reactive among the four choices:
[tex]\begin{aligned}&\text{Reactivity:} \\ & c < a < b < d\end{aligned}[/tex].
Overall, the fourth choice would be the most reactive among the four choices.
For the oxidation–reduction reaction equation
2Sc+3Br2⟶2ScBr3
indicate how many electrons are transferred in the formation of one formula unit of product.
Answers
In the formation of 1 formula unit of ScBr₃, 3 electrons are transferred.
Let's consider the following balanced redox reaction.
2 Sc + 3 Br₂ ⟶ 2 ScBr₃
We can identify both half-reactions.
Oxidation: 2 Sc ⟶ 2 Sc⁺³ + 6 e⁻
Reduction: 6 e⁻ + 3 Br₂ ⟶ 6 Br⁻
As we can see, 6 electrons are involved in the formation of 2 formula units of ScBr₃. Thus, 3 electrons are involved in the formation of 1 formula unit of ScBr₃.
In the formation of 1 formula unit of ScBr₃, 3 electrons are transferred.
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2. Why do you think electroplated jewelleries are in demand?
Chemistry plsss
Answers
Explanation:
Electroplated jeweleries are in demand because firstly they are as shiny and attractive as real jeweleries, they are also light weighted and cost effective.
A 14.0 L container at 323 K holds a mixture of two gases with a total pressure of 8.00 atm. If there are 1.50 mol of Gas A in the mixture, how many moles of Gas B are present
Answers
The number of moles of gas B present in the gas mixture is 2.72 moles.
The given parameters;
Volume of the gases, V = 14 LTemperature of the gases, T = 323 KTotal pressure of the gases, P = 8 atmNumber of moles of gas A = 1.5 molesThe total number of moles of the gases is calculated by applying ideal gas law;
PV = nRT
where;
R is ideal gas constant = 0.0821 L.atm./mol.K
n is the total mole of the gases
[tex]n =\frac{PV}{RT} \\\\n = \frac{8 \times 14}{0.0821 \times 323} \\\\n = 4.22 \ moles[/tex]
The number of moles of gas B is calculated as follows;
[tex]n_B = 4.22 - n_A\\\\n_B = 4.22 - 1.5\\\\n_B = 2.72 \ moles[/tex]
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A buffer solution was prepared by mixing 50.0 mL of a 0.100 M solution of CH3COOH with 0.500 grams of NaCH3COO. The resulting mixture is diluted to 100.0 mL. What is the pH of the solution
Answers
Answer:
100.0
Explanation:
Have a great day god bless
Someone please help me :)))
Answers
Answer:
3. solids are measured in centimeters
4. gases And liquids are measured in milliliters
Answer:
Solids are measured in Mass
Gases and Liquids are measured in Volume
Explanation:
Solids can also additionally be measured by length as well.
fun fact: natural gas is measured by volume (cubic feet) but is sold based on its heating content (Btus). A cubic foot of natural gas is the amount of natural gas that can be contained in a cube one foot on a side, at a certain standard temperature and pressure. (source; oilgaslawyer blog)
PLEASE ANWSER THIS!!
which is the best definition m of pitch?
A: pitch is how high or low a sound is
B: pitch is how loud a sound is
C: pitch is how well a sound travels through a medium
Answers
Answer:
A. because there both high pitched voice and low pitched ( girls have sweet, shrill ,high pitched good voice ) where as boys have horase ,low pitched medium voice )
Physical change does not produce a nee substance true or false
Answers
Answer:
ooooooooh .,.,.,.,.,.,
Answer:
True
TruePhysical change – A change in the size, shape, color, or state of matter of a substance. No new substance is produced.
Bas +
PtF2 →
BaF2 +
Pts
Need to balance it
Answers
it is already balanced
REACTANTS
Barium sulfide (BaS) + platinum (Ii) fluoride
PRODUCT
Barium fluoride (BaF2) + Cooperite (PtS)
Hope this answer helps you dear! take care
Oxidation unit test
Please help ASAP.
Which phrase best defines a redox reaction? (1 point)
O a reaction in which oxygen combines with different atoms
O a reaction in which electrons are transferred between different atoms
O a reaction in which electrons are released from the system
O a reaction in which the number of oxygen atoms is reduced
Answers
Answer:
a reaction in which electrons are transferred between different atoms
Explanation:
I took the test and got it right :)
c. a reaction in which electrons are released from the system
Oxidation:
Oxidation is a process which involves the addition of oxygen or any electronegative element or the removal of hydrogen or any electropositive element. In terms of electrons, oxidation is defined as the process in which an atom or ion loses one or more electrons.Oxidation occurs when the oxidation state of a molecule, atom or ion is increased. The opposite process is called reduction, which occurs when there is a gain of electrons or the oxidation state of an atom, molecule, or ion decreases.Learn more:
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A sample of crude sodium iodide was analysed by the following rection.
I- + SO42- → I2 + H2S (unbalanced)
a)Determine the oxidation number for S in SO42-.
b)The above reaction requires a basic medium. Write the balanced chemical equation. [6 marks]
Answers
A sample of crude sodium iodide was analyzed by the following balanced reaction. The oxidation number of S in SO₄²⁻ is +6.
8 I⁻ + 6 H₂O + SO₄²⁻ → 4 I₂ + H₂S + 10 OH⁻
Let's consider the following unbalanced redox reaction.
I⁻ + SO₄²⁻ → I₂ + H₂S
The oxidation number of I goes from -1 (I⁻) to 0 (I₂) so it is oxidized.The oxidation number of S goes from +6 (SO₄²⁻) to -2 (H₂S) so it is reduced.The corresponding half-reactions are:
I⁻ → I₂
SO₄²⁻ → H₂S
We will perform the mass balance adding OH⁻ and H₂O where appropriate.
2 I⁻ → I₂
6 H₂O + SO₄²⁻ → H₂S + 10 OH⁻
Then, we will perform the charge balance adding electrons where appropriate.
2 I⁻ → I₂ + 2 e⁻
8 e⁻ + 6 H₂O + SO₄²⁻ → H₂S + 10 OH⁻
Finally, we will multiply the first half-reaction by 4 and the second by 1, and add them.
4 × (2 I⁻ → I₂ + 2 e⁻)
1 × (8 e⁻ + 6 H₂O + SO₄²⁻ → H₂S + 10 OH⁻)
------------------------------------------------------------
8 I⁻ + 6 H₂O + SO₄²⁻ → 4 I₂ + H₂S + 10 OH⁻
A sample of crude sodium iodide was analyzed by the following balanced reaction. The oxidation number of S in SO₄²⁻ is +6.
8 I⁻ + 6 H₂O + SO₄²⁻ → 4 I₂ + H₂S + 10 OH⁻
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5. Select the answer for both questions
Answers
Answer:
engey
Explanation:
The process of returning mines to their original state is called ________________________.
Answers
Answer:
Mine Reclamation.Explanation:
The process of returning mines to their original state is called Mine Reclamation. HOPE THIS HELPS :)Balance the following redox reaction if it occurs in acidic solution. What are the coefficients in front of Ni and H+ in the balanced reaction? Ni2+(aq) + NH4+(aq) → Ni(s) + NO3-(aq)
Answers
In this case, the problem is asking for the balance of a redox reaction in acidic media, in which nickel is reduced to a metallic way and nitrogen oxidized to an ionic way.
Thus, according to the given information, it turns out possible for us to balance this equation in acidic solution by firstly setting up the half reactions:
[tex]Ni^{2+}+2e^-\rightarrow Ni^0\\\\N^{3-}H_4^++3H_2O\rightarrow N^{5+}O_3^-+8e^-+10H^+[/tex]
Next, we cross multiply each half-reaction by the other's carried electrons:
[tex]8Ni^{2+}+16e^-\rightarrow 8Ni^0\\\\2N^{3-}H_4^++6H_2O\rightarrow 2N^{5+}O_3^-+16e^-+20H^+[/tex]
Finally, we add them together to obtain:
[tex]8Ni^{2+}+2N^{3-}H_4^++6H_2O\rightarrow 8Ni^0+2N^{5+}O_3^-+20H^+[/tex]
Which can be all simplified by a factor of 2 to obtain:
[tex]4Ni^{2+}+N^{3-}H_4^++3H_2O\rightarrow 4Ni^0+N^{5+}O_3^-+10H^+\\\\4Ni^{2+}(aq)+NH_4^+(aq)+3H_2O(l)\rightarrow 4Ni(s)+NO_3^-(aq)+10H^+(aq)[/tex]
Hence, the coefficients in front of Ni and H⁺ are 4 and 10 respectively.
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https://brainly.com/question/14965625Each element can be indentified by the number of _______ found in its nucleus, which also equals the elements _______ _______.
Answers
true or false: When the value of secondary quantum no . (l) =1 , the magnetic quantum no . ( m ) = 3 .
Answers
When the value of secondary quantum number (l) = 1, the magnetic quantum number can be from -1 to +1. The answer would be false.
What are Quantum numbers?The angular quantum number (l) can take any integer between 0 and the value of the principal quantum number (n) less by 1.
In other words, l can be from 0 to n-1.
The magnetic quantum number (m), on the other hand, can take any value between -l to +l.
For example, if l = 1, m can be -1,0, and +1.
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A metal (FW 241.5 g/mol) crystallizes into a face-centered cubic unit cell and has a radius of 1.92 Angstrom. What is the density of this metal in g/cm3
Answers
This problem provides the molar mass and radius of a metal that has an FCC unit cell and the density is required.
Firstly, we begin with the formula that relates the aforementioned variables and also includes the Avogadro's number and the volume of the unit cell:
[tex]\rho=\frac{Z*M}{V*N_A}[/tex]
Whereas Z stands for the number of atoms in the unit cell, M the molar mass, V the volume and NA the Avogadro's number. Next, since FFC is able to hold 4 atoms and M and NA are given. Next, we calculate the volume of the atom in the unit given the radius in meters:
[tex]V=a^3=(2*1.92x10^-10m*\sqrt{2} )^3=1.60x10^{-28}m^3/atom[/tex]
And finally the required density in g/cm³:
[tex]\rho=\frac{4*241.5g/mol}{1.60x10^{-28}m^3/atom*6.022x10^{23}atom/mol} \\\\\rho=10025739g/m^3=10.03 g/cm^3[/tex]
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https://brainly.com/question/12977980https://brainly.com/question/13110055Which of the following is a way to increase pressure on a gas?
Answers
Answer:
increase the number of gas particles
Explanation:
Brainliest fast before 5:35 no link no bot
Answers
Answer:
1.) 7
2.) 5
3.) stable
4.) 5A
5.) 5
6.) The properties would be more stable to property of phosphorous because same group and valenve electronics and they also have same chemical
Explanation:
The rest i dont know
Can KI+Cl2 occur or not
Answers
Yes according to reliable sources.
What is the density of a sponge that has a mass of 100g and a volume of 10 mL?
Answers
Answer:
10
Explanation:
Equation: d = m/v
100/10 = 10
10g/ml
Explanation:
Density is the mass an object per unit of volume
what stated of matter and how many phases are present when a 5.0 mL sample of oil is mixed with 100.0 mL of water?
A both solid and liquid state= two phases
B two layers of different liquids=two phases
C the liquid state only= one phases
D the solid state only=one phase
Answers
two layers of different liquids=two phases.
Because oil doesn't dissolve in water. It only floats on water.
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Doing Labs at home
I’m a junior and I’m staying home for this semester and I have to take chemistry and a lot of my work is Labs but I don’t know how to do them since I don’t have the materials at home to do the labs. Someone please help!!!
Answers
Answer:
go get the stuff.
Explanation:
can someone tell me if I got this right? so I'm supposed to Match the vocabulary terms with their detentions
Answers
Answer:
I hope that help you
Explanation:
energy is change from one form to another called _energy conversion
energy can neither be created nor destroyed it can only be transformed from one form to another called --The law of conservation of energy
cause to change in form character or function called - convert
the last sentensce
energy transformation
