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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https://brainly.com/question/22818252 https://brainly.com/question/9680530as the solar nebula cooled which compounds were the first to condense from a gas to a solid? Rock water ice or metal
As the solar nebula cooled METAL compounds are the first to condense from a gas to a solid. The solar nebula gave birth to the Solar system.
A solar nebula is a disc-shaped cloud of gases and grain dust, which gave birth to the Sun and planets of the Solar system, approximately 4.6 billion years ago.
The solar nebula is at the beginning a mixture of interstellar gases (hydrogen and helium) and dust grains.
As the solar nebula cools, heavy elements such as metals in the disk condensate into planetesimals.
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Thin-layer chromatography explain ?????
Answer:
Explanation:
Thin-layer chromatography (TLC) is a chromatography technique used to separate non-volatile mixtures. ... After the sample has been applied on the plate, a solvent or solvent mixture (known as the mobile phase) is drawn up the plate via capillary action.
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Water waves in a small tank are 6.0 cm long. They pass at a given point at a rate of 4.8 waves per second. What is the speed of the wave?
Answer:, Correct option is 0.288m/s
Explanation:
The relationship between the velocity of the wave, its wavelength and frequency is given by the formula
Wavelengthλ=
Frequency(ν)
Speed(v)
,
where, v - velocity of the wave
λ - wavelength of the wave
f - frequency of the wave.
In the question it is given that the frequency is 4.8 Hz and the wavelength is 6.0 cm, that is, 0.06 meters.
The velocity of the sound is calculated as follows.
v=f×λ=4.8 Hz×0.06 m=0.288 m/s
Hence, the speed of the water wave is 0.288 m/s.
which two types of food are homogeneous mixtures
A. mustard
B. mayonnaise
C. tossed salad
D. trail mix
What identifies the number of protons in the nucleus of an atom?
Answer: Atomic number
Explanation:
I hope this helps you!
a. Calculate the change in enthalpy when 20.0 grams of aluminum metal is heated from 298 K to 573 K at constant pressure of 1 atm.
b. Calculate the change in enthalpy when 20.0 grams of metallic lead is taken through the same process. In both cases assume the heat capacity values predicted by equipartition are valid through the temperature range stated.
For the reaction C + O2 = CO2, if 3 grams of carbon react with the oxygen, how many grams of carbon dioxide are produced?
Pleeeeasee someone who’s good at chemistry?! 10 grade
ASAP
I’ll give points, just help please
Answer:
where is the question????????????
If 38.6 grams of iron react with an excess of bromine gas, what mass of FeBr2 can form?
Answer:
›› FeBr2 molecular weight. Molar mass of FeBr2 = 215.653 g/mol. This compound is also known as Iron(II) Bromide. Convert grams FeBr2 to moles or moles FeBr2 to grams. Molecular weight calculation: 55.845 + 79.904*2 ›› Percent composition by element
Explanation:
If 38.6 grams of iron react with an excess of bromine gas, the mass of FeBr2 can form is 149 grams.
What is mass?Mass is defined as a way to gauge how much matter there is in a substance or thing. The kilogram (kg) is the fundamental SI unit of mass, while lower masses can also be measured in grams (g). Atoms make up everyday matter. A majority of an atom's mass is contained in its nucleus.
Given Fe = 38.6 g.
Fe has a molar mass = 55.845 g/mol.
Given mass/molar mass equals 38.6g/55.845gmol-1, or 0.6912 moles of iron.
The reaction is described as Fe + Br2 FeBr2.
One mole Fe yields 1 mole of FeBr2.
FeBr2 would be produced from 0.6912 moles of Fe.
FeBr2 has a molar mass of 215.65 g/mol.
Moles of FeBr2 x Molar mass of FeBr2
= 215.65 g/mole x 0.6912 mole
= 149.06 g FeBr2 produced is the formula.
Thus, if 38.6 grams of iron react with an excess of bromine gas, the mass of FeBr2 can form is 149 grams.
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How many atoms are in mercury (I) phospate?
The chemical formula is (Hg2)3(PO4)2
A)11
B)14
C)15
D)16
Mercury (I) phosphate with the chemical formula (Hg2)3(PO4)2 has 16 atoms.
Number of Hg atoms = 2x3 = 6Number of P atoms = 2 x 1 = 2Number of O atoms = 4x2 = 8Sum of all the atoms = 6+2+8
= 16 atoms
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Convert 1.36x10 to standard form
Answer:
13.6 is the correct answer written in standard form.
Explanation:
1.36, move the decimal once to the right to get 13.6
Answer:
13.6
Explanation:
The standard form is 13.6
Fill in the left side of this equilibrium constant equation for the reaction of benzoic acid with water
Answer:
C6H5CO2H (aq) + H2O (l) _C6H5CO2- + H3OFind five household items that contain ionic compounds. List the following information for each compound: a.name of the product
b. the chemical name of the ionic compound
d.the chemical formula of the ionic compound c. identify the ions present in each compound
Answer:
D . GOD BLESS .
Explanation:
Suppose that in an equilibrium mixture of HCl, Cl2, and H2, the concentration of H2 is 1.0 x 10-11 mol-L-1and that of Cl2 is 2.0 x 10-10 mol-L-1. What is the equilibrium molar concentration of HCl at 500 K, given Kc = 4.0 x 1018 for H2(g) +Cl2(g) ⇆ 2HCl(g).
Considering the definition of Kc, the equilibrium molar concentration of HCl at 500 K is 0.0894 [tex]\frac{mol}{L}[/tex].
The balanced reaction is:
H₂(g) +Cl₂(g) ⇆ 2 HCl(g)
Equilibrium is a state of a reactant system in which no changes are observed as time passes, despite the fact that the substances present continue to react with each other. In other words, reactants become products and products become reactants and they do so at the same rate.
In other words, chemical equilibrium is established when there are two opposite reactions that take place simultaneously at the same speed.
The concentration of reactants and products at equilibrium is related by the equilibrium constant Kc. Its value in a chemical reaction depends on the temperature and the expression of a generic reaction aA + bB ⇄ cC is
[tex]K_{c} =\frac{[C]^{c} x[D]^{d} }{[A]^{a} x[B]^{b} }[/tex]
That is, the constant Kc is equal to the multiplication of the concentrations of the products raised to their stoichiometric coefficients by the multiplication of the concentrations of the reactants also raised to their stoichiometric coefficients.
In this case, the constant Kc can be expressed as:
[tex]K_{c} =\frac{[HCl]^{2} }{[H_{2} ]x[Cl_{2} ] }[/tex]
You know that in an equilibrium mixture of HCl, Cl₂, and H₂:
the concentration of H₂ is 1.0×10⁻¹¹ [tex]\frac{mol}{L}[/tex]the concentration of Cl₂ is 2.0×10⁻¹⁰ [tex]\frac{mol}{L}[/tex]Kc=4×10¹⁸Replacing in the expression for Kc:
[tex]4x10^{18} =\frac{[HCl]^{2} }{[1x10^{-11} ]x[2x10^{-10} ] }[/tex]
Solving:
[tex]4x10^{18} =\frac{[HCl]^{2} }{2x10^{-21} }[/tex]
[tex]4x10^{18} x 2x10^{-21}=[HCl]^{2}[/tex]
[tex]8x10^{-3} =[HCl]^{2}[/tex]
[tex]\sqrt[2]{8x10^{-3}} =[HCl][/tex]
0.0894 [tex]\frac{mol}{L}[/tex]= [HCl]
Finally, the equilibrium molar concentration of HCl at 500 K is 0.0894 [tex]\frac{mol}{L}[/tex].
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The molarity of the solution is 0.01.
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Oxidation unit test
Please help ASAP!!!
Which statement correctly describes the oxidation number of the manganese atom (Mn) in Mnl2 and MnO2?
O Manganese has an oxidation number of +4 in Mnl2 and +2 in MnO2.
o Manganese has an oxidation number of +2 in Mnl2 and +4 in MnO2.
o Manganese has an oxidation number of +4 in both Mnl2 and MnO2.
Manganese has an oxidation number of +2 in both Mnl2 and MnO2.
In this case, according to the given information about the oxidation numbers and the compounds given, it turns out possible to figure out the oxidation number of manganese in both MnI2, manganese (II) iodide and MnO2, manganese (IV) oxide, by using the concept of charge balance.
Thus, we can define the oxidation state of iodine and oxygen as -1 and -2, respectively, since the former needs one electron to complete the octet and the latter, two of them.
Next, we can write the following [tex]x[/tex], since manganese has five oxidation states, and it is necessary to calculate the appropriate ones:
[tex]Mn^xI_2^-\\\\Mn ^xO_2^{-2}[/tex]
Next, we multiply each anion's oxidation number by the subscript, to obtain the following:
[tex]Mn^xI_2^-\rightarrow x-2=0;x=+2\\\\Mn ^xO_2^{-2}\rightarrow x-4=0;x=+4[/tex]
Thus, the correct choice is Manganese has an oxidation number of +2 in Mnl2 and +4 in MnO2.
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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!!!
Answer:
go get the stuff.
Explanation:
Environmental scientists collect air samples so they can test the quality of the air. They start with rigid metal containers that are completely empty—the air has been pumped out of them.
What happens to the pressure inside the container and the volume of the container as air enters it?
Explanation:
filling air inside an empty o2 medal containers, if air is added, the air inside, creates volume inside.
due to heat, weather,... depending on what indoor or outdoor storage said containers r placed in,;
So, I can't give you an answer, due to lack of details..sorry...
3.00 L of a gas is collected at 35.0 C and 0.93 atm. What is the volume at STP
Suppose you have samples of three unknown solids. Explain how you could use their properties to
determine whether or not they are ionic solids.
Using melting and boiling temperature, hardness and electric current passing testing.
Ionic solidsIonic solids are materials that have a strong bond between their ions, thus producing well-defined shapes.
In addition, due to this strong attraction, the boiling and melting temperatures of these materials are very high, in addition to the resistance to breakage presented by them.
Finally, ionic solids are also excellent conductors of electricity.
So, their properties used to determine whether or not they are ionic solids are melting and boiling temperature, hardness and electric current passing testing.
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Find the volume of 0.170 M sulfuric acid necessary to react completely with 72.2 g sodium hydroxide.
The volume of sulphuric acid, H₂SO₄ needed for the complete reaction with 72.2 g of sodium hydroxide, NaOH is 5.31 L
We'll begin by calculating the number of mole in 72.2 g of NaOH. This can be obtained as follow:
Mass of NaOH = 72.2 g
Molar mass of NaOH = 23 + 16 + 1 = 40 g/mol
Mole of NaOH =?Mole = mass / molar mass
Mole of NaOH = 72.2 / 40
Mole of NaOH = 1.805 mole Next, we shall determine the number of mole of H₂SO₄ needed to react with 1.805 mole of NaOH.2NaOH + H₂SO₄ —> Na₂SO₄ + 2H₂O
From the balanced equation above,
2 moles of NaOH reacted with 1 mole of H₂SO₄.
Therefore,
1.805 mole of NaOH will react with = 1.805 / 2 = 0.9025 mole of H₂SO₄.
Finally, we shall determine the volume of H₂SO₄.Mole of H₂SO₄ = 0.9025 mole
Molarity of H₂SO₄ = 0.170 M
Volume of H₂SO₄ =?Volume = mole / Molarity
Volume of H₂SO₄ = 0.9025 / 0.170
Volume of H₂SO₄ = 5.31 LThus, the volume of H₂SO₄ needed for the reaction is 5.31 L
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