The freezing point depression of a solution that contains 2 moles of NaCl in 200 g of water (Kf = 1.86 °C/m) is 18.6 °C.
What is the freezing point depression?It is a decrease in the freezing point of a solution, in comparison with the pure solvent.
Step 1. Determine the molality of the solution.The solution contains 2 moles of NaCl in 200 g of water.
b = moles NaCl / Kg water = 2 mol/0.200 kg = 10 m
Step 2. Calculate the freezing point depression.Given the cryoscopic constant (Kf) is 1.86 °C/m for water, the freezing point depression (ΔT) is:
ΔT = Kf × b = 1.86 °C/m × 10 m = 18.6 °C
The freezing point depression of a solution that contains 2 moles of NaCl in 200 g of water (Kf = 1.86 °C/m) is 18.6 °C.
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The chemical equation below shows the reaction of magnesium and oxygen which combine to form magnesium oxide.
Mg + O = MgO
In this equation, magnesium and oxygen are the _____
•reactants
•products
Help plz
Question 10 of 35
A red blood cell can be used to model a typical animal cell.
What would happen to a red blood cell placed in very salty water?
O A. It would stay the same size because salt cannot cross the cell
membrane.
B. It would swell and burst as water moves into the cell, where there
is a higher concentration of water.
C. It would swell and burst because salt would be transported across
the cell membrane.
O D. It would shrink as water moves out of the cell to where there is a
lower concentration of water.
A metal ion (X) with a charge of 4+ is attracted to non metal ion (Z) with a charge of 3-. Which of these formulas represents the resulting compound? I need answers asap please
Answer: [tex]X_3Z_4[/tex]
Explanation:
For formation of a neutral ionic compound, the charges on cation and anion must be balanced. The cation is formed by loss of electrons by metals and anions are formed by gain of electrons by non metals.
Here metal X is having an oxidation state of +4 called as [tex]X^{4+}[/tex] cation and [tex]Z^{3-}[/tex] is an anion with oxidation state of -3. Thus they combine and their oxidation states are exchanged and written in simplest whole number ratios to give neutral [tex]X_3Z_4[/tex]
[tex]X_3Z_4[/tex] is the formula of the resulting compound.
It is often possible to change a hydrate into an anhydrous compound by heating it to drive off the water (dehydration). Write an equation that shows the dehydration of manganese(II) sulfate pentahydrate . Use an asterisk to enter the dot.
Answer:
MnSO4.5H2O(s) ---------> MnSO4(s) + 5H2O(g)
Explanation:
The dehydration of a hydrate implies that the water of crystallization is lost. Water of crystallization is included in the crystal structure as it is formed and is incorporated into the structure of the compound.
Now the equation for the dehydration of manganese(II) sulfate pentahydrate is;
MnSO4.5H2O(s) ---------> MnSO4(s) + 5H2O(g)
The MnSO4 is now said to be anhydrous.
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The following diagram shows a stage of a cell during mitosis.
Which of the following happens to the cell during the stage shown in the diagram? The chromosomes are replicated.
The chromosomes start to condense.
The chromosomes line up in the middle.
The chromosomes begin to uncoil and form chromatin.
Answer:
I promise it is the 2nd one
Explanation:
The following diagram shows a stage of a cell during mitosis. Two identical circles are joined in the middle and they have the nucleolus inside the nucleus in the center of the circles.
Answer:
The Second One
Explanation:I did the test and got this question correct
Pls comment :D
A helium balloon has a volume of 36 L. The pressure of the helium gas in the balloon is 132 kPa and its temperature is 27 degrees Celsius. How many moles of helium are in the balloon?
Answer:
[tex]n =1.905mol[/tex]
Explanation:
Hello!
In this case, by considering helium gas as an ideal one, we can use the following equation:
[tex]PV=nRT[/tex]
Whereas P should go in atmospheres and T in Kelvins; thus we proceed as follows:
[tex]n=\frac{PV}{RT}=\frac{132kPa*\frac{1atm}{101.325kPa}*36L}{0.08206\frac{atm*L}{mol*K}(27+273)K} =1.905mol[/tex]
Best regards!
How does fertilizer benefit the daily lives of people?
Answer:
Fertilizers play an important role in providing crops with the nutrients they need to grow and be harvested for nutritious food. Fertilizers help deliver enough food to feed the world's population. ...
For example, micronutrients such as zinc are important to human nutrition, especially children.
Explanation:
Hope it is helpful.....
73. Wind blows off of the ocean cooling the land near the ocean. This is an example of what type of heat transfer?
convection
induction
conduction
radiation
Help plz
Answer:
Convection
Explanation:
Convection is the circular motion that happens when warmer air or liquid — which has faster moving molecules, making it less dense — rises, while the cooler air or liquid drops down.
Same as in the case of sea breeze where the the lighter wind in surface of land rises up and the cooler wind from the sea comes to fill up that place. This is an example of convection.
what are three limitations of current cloaking technology.
Get this correct I'll give you 40 points.
Explanation:
1.undetectable to electromagnetic waves
2.hiding an object from an illumination containing diffre t wave lengths become difficult as the object sizes grow.
3. reduce the scattering by two orders.
Electromagnetic waves are unable to detect it. With increasing item sizes, it becomes more challenging to conceal an object from an illumination with various wave lengths. two orders down on the scattering.
What is current cloaking technology?
Current clocking technology is defined as a hypothetical or made-up stealth technology that makes things like people or spaceships completely or partially invisible to certain electromagnetic (EM) spectrum wavelengths. In a specific frequency band, this gadget renders an object "invisible" to electromagnetic radiation. Obviously, cloaks that operate in the visible spectrum have the most fascinating potential uses.
These metamaterials, according to the researchers, can shield a medium-sized antenna from radio waves over a wide range of bandwidths, resulting in clearer communications. However, as visible light wavelengths are far shorter than radio waves, it is practically difficult to conceal huge things from them, such as the human body. The issue with present designs is that they can only handle a certain amount of bandwidth. Even this "perfect" 3D cloak that was previously exhibited could only conceal items from microwaves.
Thus, electromagnetic waves are unable to detect it. With increasing item sizes, it becomes more challenging to conceal an object from an illumination with various wave lengths. two orders down on the scattering.
To learn more about current cloaking technology, refer to the link below:
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Burning plants contributes to global warming because:
a) carbon dioxide is released during combustion
b) there are no trees to provide shade
c) much oxygen is used up during combustion
d) the sun beats on the bare soil.
Answer:carbon dioxide is released during combustion
A normal adult jawbone contains 200 mg of Carbon-14 in a living person. If scientists found a jawbone that only had 50mg of Carbon-14, how old is the bone? (The half-life of C-14 is 5730 years).
Carbon-14 is a radioisotope of carbon that decays following first-order kinetics. There are four values of interest in this problem: the "normal" (or original) amount of carbon-14 for a jawbone ([tex]\mathrm{N_0}[/tex]), the actual amount of carbon-14 in a jawbone ([tex]\mathrm{N}[/tex]), the half-life of carbon-14 ([tex]\mathrm{t_{1/2}}[/tex]), and the actual time elapsed ([tex]\mathrm{t}[/tex]) from the original time. There is an equation that ties all these values in together,
[tex]N= N_0 e^{-kt}[/tex]
where k is the rate constant, which, for first-order decay, is related to the half-life by
[tex]k = \dfrac{\ln 2}{ t_{1/2} }.[/tex]
What you want to find here is the time elapsed (t). So, you can substitute the latter equation for k into the k in the former equation to get
[tex]N= N_0 e^{\frac{-\ln 2 \;t}{t_{1/2}}.[/tex]
Rearranging to solve for t, the equation becomes
[tex]t = \left(\dfrac{\ln \dfrac{N_0}{N}}{\ln 2} \right) t_{1/2}.[/tex]
You are given all three of the values necessary to solve for t: The normal amount of carbon-14 is 200 mg; the actual amount of carbon-14 in the sample is 50 mg; and the half-life of carbon-14 is 5730 years. Plugging them into the above equation, we get
[tex]t = \left(\dfrac{\ln \dfrac{200 \text{ mg}}{50 \text{ mg}}}{\ln 2} \right) \left(5730 \text{ years} \right) = 11460 \text{ years}.[/tex]
So the jawbone found is 11460 years old (or 11000 if accounting for sig figs).
The bond order for a double bond is
Answer:
B.Two
Explanation:
Dividend
Divisor
Quotient/ Remainder
SAGOT
75
21
16.) 54
17.) 108
18.) 380
19.) 633
20.) 648
27
76
57
32
Solo
nihanda ni:
NNA MARIE S. CARAIT
borrinoloticon
Answer:
Dividend Divisor Quotient/ Remainder SAGOT 75 21 16.) 54 17.) 108 18.) 380 19.) 633 20.) 648 27 76 57 32. Solo nihanda ni: NNA MARIE S.
Explanation:
When comparing the two elements K and Ge , the more metallic element is__________ based on periodic trends alone.
When comparing the two elements Sb and Pb , the more metallic element is___________ based on periodic trends alone.
a. Ge
b. Pb
c. Sb
d. K
e. Impossible to determine
Answer:
Option D and Option B
When comparing the two elements K and Ge , the more metallic element is_____K_____ based on periodic trends alone.
When comparing the two elements Sb and Pb , the more metallic element is_____Pb______ based on periodic
Explanation:
The metallic characteristic increases when we move down a column in a periodic table or when we move left in the row.
Potassium and Germanium are located on the same row, but germanium lies on the right side of potassium. Thus, potassium (K) is more metallic than Germanium (Ge)
While Lead (Pb) lies to left of Sb in the adjacent column and is also lies below Sb. Hence Pb is more metallic than Sb
1. Fill in the blanks. Example: A nitrogen atom takes on a 3- charge when it forms an anion and becomes nitride. a. A magnesium atom takes on a ___ charge when it forms a(an) ____ion and becomes . b. A chlorine atom takes on a ___ charge when it forms a(an) ____ion and becomes . c. An oxygen atom takes on a ___ charge when it forms a(an) ____ion and becomes . d. A potassium atom takes on a ___ charge when it forms a(an) ____ion and becomes .
Answer: a. +2, cation and magnesium ion .
b. -1, anion, chloride
c. -2, anion, oxide
d. +1. cation , potassium ion
Explanation:
When an atom accepts an electron negative charge is created on atom and is called as anion.
When atom loses an electron positive charge is created on atom and is called as cation.
Magnesium (Mg) with atomic number of 12 has electronic configuration of 2,8,2 and thus it can lose 2 electrons to form [tex]Mg^{2+}[/tex] cation and becomes magnesium ion.
Chlorine (Cl) with atomic number of 17 has electronic configuration of 2,8,7 and thus it can gain 1 electron to form [tex]Cl^{-}[/tex] anion and becomes chloride.
Oxygen (O) with atomic number of 8 has electronic configuration of 2,6 and thus it can gain 2 electrons to form [tex]O^{2-}[/tex] anion and becomes oxide.
Potassium (K) with atomic number of 19 has electronic configuration of 2,8,8,1 and thus it can lose 1 electron to form [tex]K^{+}[/tex] cation and becomes potassium ion.
You are boiling water to cook some noodles. You notice bubbles forming on the bottom of the pot. Your brother thinks it is a chemical change. Is he correct?
Yes. The bubbles contain hydrogen and oxygen that separated from the water.
Yes. The bubbles are now filled with air.
No. The water changes into carbon dioxide.
No. It is a physical change when water is heated and is converted into water vapor.
Answer:
i think its Yes. The bubbles contain hydrogen and oxygen that separated from the water but i could be wrong so i would just wait to see if anybody else says anything
Explanation:
Specific Gravity is also known as ______________
2NH3+2O2- N2O+3H2O
If 80.0 grams of O2 reacted in above reaction ,how many grams of N2O will be produced?
Answer:
55.0125 grams NO2
Explanation:
So we have 80 grams of O2, first convert to moles
80 g O2 * 1 mol/32 g O2 = 2.5 mol O2
Next use the mole ratio of O2 to NO2
2.5 mol O2* 1 mol NO2/2 mol NO2=1.25 mol NO2
Since the question is asking how many grams, convert NO2 to grams
1.25 mol NO2 * 44.01 NO2/1 mol NO2= 55.0125 grams
Why are there elements on the bottom of the periodic table? What’s the name of this group of elements?
Answer
The lanthanides and actinides are separated from the rest of the periodic table, usually appearing as separate rows at the bottom. The reason for this placement has to do with the electron configurations of these elements
Explanation:
Scientists Believe that:
A. The continents are shifting
B. The world was once one big mass
C. The center of the earth is made of iron and nickel
D. All of the above
E. None of the above
Answer: D
Explanation: Today, we know that the continents rest on massive slabs of rock called tectonic plates. They are constantly in movement and they are responsible for several natural disasters. Approximetly 335 million years ago, during the late Paleozoic and early Mesozoic eras, the world was one big mass, called Pangea, which eventually would start to break apart about 175 million years ago. At the center of the Earth is the core, which has two parts. The solid, inner core of iron has a radius of about 760 miles (about 1,220 km), according to NASA. It is surrounded by a liquid, outer core composed of a nickel-iron alloy.
I hope it helps
Answer:
the answer is D
Explanation:
To run a spectrophotometry experiment, begin by _________ the spectrophotometer and preparing the samples. Be sure to select the correct ________, then run a measurement on the _________ solution. Follow up by running measurements on _______solutions. Once data is collected, turn off the instrument, clean the area, and discard the samples.
Answer:
To run a spectrophotometry experiment, begin by warming up the spectrophotometer and preparing the samples. Be sure to select the correct wavelength, then run a measurement on the blank solution. Follow up by running measurements on sample solutions. Once data is collected, turn off the instrument, clean the area, and discard the samples.
Explanation:
The spectrophotometer is a device used in laboratories to carry out analysis in experiments that need to measure and compare the amount of light absorbed or transmitted between samples, regardless of whether the samples are transparent or opaque solid. The spectrophotometer can be single-beam and double-beam. Regardless of the nature of the beam, to perform a spectrophotometry experiment, you must start by heating the spectrophotometer and preparing the samples. Make sure to select the correct wavelength and perform a measurement on the blank solution. Follow up by performing measurements on sample solutions. Once the data is collected, turn off the instrument, clean the area and discard the samples.
An analytical chemist is titrating of a solution of ethylamine with a solution of . The of ethylamine is . Calculate the pH of the base solution after the chemist has added of the solution to it. Note for advanced students: you may assume the final volume equals the initial volume of the solution plus the volume of solution added. g
Answer:
pH=11.
Explanation:
Hello!
In this case, since the data is not given, it is possible to use a similar problem like:
"An analytical chemist is titrating 185.0 mL of a 0.7500 M solution of ethylamine(C2HNH2) with a 0.4800 M solution of HNO3.ThepK,of ethylamine is 3.19. Calculate the pH of the base solution after the chemist has added 114.4 mL of the HNO3 solution to it"
Thus, for the reaction:
[tex]C_2H_5NH_2+H^+\rightleftharpoons C_2H_5NH_4^+[/tex]
Tt is possible to compute the remaining moles of ethylamine via the following subtraction:
[tex]n_{ethylamine}=0.1850L*0.7500mol/L=0.1365mol\\\\n_{acid}=0.1144L*0.4800mol/L=0.0549mol\\\\n_{ethylamine}^{remaining}=0.1365mol-0.0549mol=0.0816mol[/tex]
Thus, the concentration of ethylamine in solution is:
[tex][ethylamine]=\frac{0.0816mol}{0.1850L+0.1144L}=0.2725M[/tex]
Now, we can also infer that some salt is formed, and has the following concentration:
[tex][salt]=\frac{0.0549mol}{0.1850L+0.1144L}=0.1834M[/tex]
Therefore, we can use the Henderson-Hasselbach equation to compute the resulting pOH first:
[tex]pOH=pKb+log(\frac{[salt]}{[base]} )\\\\pOH=3.19+log(\frac{0.1834M}{0.2725M})\\\\pOH=3.0[/tex]
Finally, the pH turns out to be:
[tex]pH=14-pOH=14-3\\\\pH=11[/tex]
NOTE: keep in mind that if you have different values, you can just change them and follow the very same process here.
Best regards!
One mole of hydrogen is equal to____
What is the coefficient of iron(lll) carbonate?
Fe(NO3)3 + (NH4)2CO3
? Fe2(CO3)3 + NH4NO3
PLEASE HELP ME ITS DUE IN 25 MINUTES True or false iron and nickel are less dense than silicates ?
A compound is 22.5% nitrogen and 77.5% oxygen, What is the empirical formula of
this compound?
Answer:
[tex]NO_3[/tex]
Explanation:
Hello!
In this case, since percent compositions are used to set up empirical formulas when assuming those percentages are masses, we can fist compute the moles of nitrogen and oxygen in the compound as shown below:
[tex]n_N=22.5g/14.01g/mol=1.61mol\\\\n_O=77.5g/16.00g/mol=4.84mol[/tex]
Now, we divide by the fewest moles to compute the subscripts:
[tex]N=\frac{1.61}{1.61} =1\\\\O=\frac{4.84}{1.61} =3[/tex]
Thus, the empirical formula turns out:
[tex]NO_3[/tex]
Best regards!
How many zinc atoms are contained in 3.75 moles of zinc?
2.26 × 10²⁴ atoms Zn
General Formulas and Concepts:Math
Pre-Algebra
Order of Operations: BPEMDAS
Brackets Parenthesis Exponents Multiplication Division Addition Subtraction Left to RightChemistry
Atomic Structure
Reading a Periodic TableAvogadro's Number - 6.022 × 10²³ atoms, molecules, formula units, etc.Stoichiometry
Using Dimensional AnalysisExplanation:Step 1: Define
3.75 mol Zn (Zinc)
Step 2: Identify Conversions
Avogadro's Number
Step 3: Convert
[DA] Set up: [tex]\displaystyle 3.75 \ mol \ Zn(\frac{6.022 \cdot 10^{23} \ atoms \ Zn}{1 \ mol \ Zn})[/tex][DA] Multiply/Divide [Cancel out units]: [tex]\displaystyle 2.25825 \cdot 10^{24} \ atoms \ Zn[/tex]Step 4: Check
Follow sig fig rules and round. We are given 3 sig figs.
2.25825 × 10²⁴ atoms Zn ≈ 2.26 × 10²⁴ atoms Zn
Someone please help me I’m so stuck I cannot find the empty ones that were not filled in :(. I’m really confused
Answer:
Positive charges: 2
Negative charges: 1
Overall charge: +1
Explanation:
In Diagram B we have the chemical element Helium (He). You can see in the Periodic Table that He has an atomic number of 2 and an atomic mass of approximately 4.
The atomic number is equal to the number of protons, so He has 2 protons. The protons are the positive charges in the atom, so the number of positive charges is 2. That is invariable, if the number of protons - or the atomic number - of an atom changes, it changes its identity.
In the drawing, we can see that the nucleus is composed of 2 protons (2 'p' particles) and 2 neutrons (2 'n' particles). The atomic mass is calculated as the number of protons and neutrons, so 2 protons+ 2 neutrons = 4.
The surrounding particle with an 'e' is an electron. So, we have 1 electron. Electrons are negative charges, so the number of negative charges is 1.
Now, we can calculate the overall charge. We add the positive charges (protons) and negative charges (electrons). Each proton has a +1 charge, whereas each electron has a -1 charge. Finally, we perform the addition:
Overall charge= (number of protons x charge) + (number of electrons x charge) = (2 x (+1)) + (1 x (-1)) = (+2) + (-1) = +1
The vapor pressure of liquid pentane, C5H12, is 40.0 mm Hg at 244 K. A sample of C5H12 is placed in a closed, evacuated container of constant volume at a temperature of 409 K. It is found that all of the C5H12 is in the vapor phase and that the pressure is 62.0 mm Hg. If the temperature in the container is reduced to 244 K, which of the following statements are correct?
a. No condensation will occur.
b. The pressure in the container will be 100. mm Hg.
c. Only pentane vapor will be present.
d. Some of the vapor initially present will condense.
e. Liquid pentane will be present.
Answer:
b. The pressure in the container will be 100mm Hg.
d. Some of vapor initially present will condense.
Explanation:
The vapor pressure of liquid Pantene rises when there is container where evacuation of water molecules is restricted. The pressure inside the container rises to 100 mm Hg and then liquid molecules start condensing. These molecule form vapors.
IUPAC name for c2h2cl2?
Answer:
okay that is cool
Explanation:
Answer:
I hope it helps u! :)
Explanation: