Answer:
sink
Explanation:
The Intermolecular force of attraction exists within the water molecule. This type of intermolecular force of attraction is known as a hydrogen bond. A hydrogen bond is a dipole-dipole intermolecular attraction that occurs when hydrogen is covalently bonded to highly electronegative elements of a small atomic size.
When the heat is applied to this intermolecular force, the heat disrupts the intermolecular force, and the surface tension is being broken. This is what caused a hot needle to sink when placed in cold water. But when a cold needle is placed on the surface of warm water, the cold needle will not break up the warm water's surface tension. As a result, the cold need sinks in the warm water.
what's another name for chemical change
Answer:
chemical action; chemical change; chemical process.
Explanation:
Answer: Chemical reaction
There are billions of stars in the known universe. None of them seem to be as bright as the Sun. Which statement gives the best reason why the Sun appears to be the brightest star? A. All-stars have the same apparent brightness, but the Sun has more absolute brightness. B. The Sun is the biggest of all the stars and therefore has the greatest absolute brightness. C. The Sun is the hottest of all the stars and therefore has the greatest absolute brightness. D. The Sun is the closest star to Earth and so it seems brighter than distant stars that have much greater absolute brightness.
Answer:
The answer is D. The Sun is the closest star to Earth and so it seems brighter than distant stars that have much greater absolute brightness.
Explanation: Stars like red super giants like beetleguise are way brighter and bigger than the sun, but the sun is closest to the earth. It is only in its main sequence stage but seems bright because of its short distance from the sun( 93 million miles).
There are billions of stars in the known universe, none of them seem to be as bright as the Sun beacuse the Sun is the closest star to Earth.
What are stars?Stars are those astronomical bodies which are formed by the mixture of gases mainly of hydrogens and heliums, which are held by its own gravity.
In the universe or in the sky many stars are present which are luminous in appearance but among all of them only sun looks like more brighter, because the distance between the earth and the sun is not that much high as in between the other stars. That's why sun looks more brighter rather than other stars.
So, the Sun is the closest star to Earth and so it seems brighter than distant stars that have much greater absolute brightness.
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in a triple beam balance how do you know when you have to move a weight back to the previous notches or grooves
Answer:
sdipgjaeri0ae
Explanation:
Suppose you were to read about a scientific statement based on data from hundreds of years of research and observation that applies to a broad set of naturally occurring events. Would you consider it a hypothesis or a theory? a) hypothesis b) theory c) both d) neither
Answer:
theory
Explanation:
A theory has been tested and proven several times and oftentimes has a large amount of information, research, and evidence standing behind it.
Hope this helps! :)
Select all the correct locations on the image. In this diagram, which subatomic particles have a negative charge?
Answer:
The correct answer is: (E), Electron.
Explanation:
There are three types of subatomic particles - protons (P) have a positive charge, neutrons (N) have zero charge, and electrons (E) have a negative charge.
Hope this helps!
To see the number of atoms of an element in a given molecule we need to multiply stoichiometry to the number that is written on the foot of the element that is stoichiometry. Therefore, electron is the subatomic particles that have a negative charge.
What is atom?Atom is the smallest particle of any element, molecule or compound. Atom can not be further divided. Atoms contains nucleus in its center and electron that revolve around the atom in fixed orbit.
In the nucleus, proton and neutron are present. Electron has -1 charge while proton has +1 charge. Neutron is neutral that is it has no charge. So overall the charge of nucleus is due to only proton, not by neutron.
Therefore, electron is the subatomic particles that have a negative charge.
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Three structural isomers have the formula C5H12 . Draw the three different isomers according to the number of carbon atoms in their main chain. Be sure to draw all hydrogens.
Answer:
Explanation:
The name of the compound, C₅H₁₂, is pentane. It is a member of the alkane family hence it is saturated (no double or triple bond within it's carbon chain) and SP³ hybridized. It's three structural isomers are shown (drawn) in the attachment below. The three structural isomers are n-pentane, 2-methylbutane and 2,2-dimethylpropane.
When of a certain molecular compound X are dissolved in of benzonitrile , the freezing point of the solution is measured to be . Calculate the molar mass of X. If you need any additional information on benzonitrile, use only what you find in the ALEKS Data resource. Also, be sure your answer has a unit symbol, and is rounded to significant digit.
Answer:
49.0g/mol is molar mass of X
Explanation:
551mg of X are dissolved in 100g of benzonitrile
Freezing point of solution: -13.4°C
The freezing point depression of a solution (Colligative property) follows the equation:
ΔT = Kf*m*i
Where ΔT is change in freezing point from the pure solvent (Benzonitrile: -12.8°C) to the solution (-13.4°C)
Kf is freezing point depression of benzonitrile: 5.34°C/m
m is molality of the solution (Moles X / kg of benzonitrile)
And i is Van't Hoff factor (1 for any solute in benzonitrile)
ΔT = -12.8°C - (-13.4°C) = 0.6°C
Solving for molality of the solution:
ΔT = Kf*m*i
0.6°C = 5.34°C/m*m*1
0.1124m = molality of the solution
Moles of X are:
0.1124mol/kg benzonitrile * 0.1kg benzonitrile = 0.01124 moles X
In 551mg = 0.551g:
Molar mass:
0.551g / 0.01124mol =
49.0g/mol is molar mass of X
The equilibrium concentrations of the reactants and products are [HA]=0.280 M, [H+]=4.00×10−4 M, and [A−]=4.00×10−4 M. Calculate the value of pKa for
Answer:
6.24
Explanation:
The following data were obtained from the question:
Concentration of HA, [HA] = 0.280 M,
Concentration of H+, [H+] = 4×10¯⁴ M
Concentration of A-, [A−] = 4×10¯⁴ M
pKa =.?
Next, we shall write the balanced equation for the reaction. This is given below:
HA <===> H+ + A-
Next, we shall determine the equilibrium constant Ka for the reaction. This can be obtained as follow:
Equilibrium constant for a reaction is simply the ratio of concentration of the product raised to their coefficient to the concentration of the reactant raised to their coefficient.
The equilibrium constant for the above equation is given below:
Ka = [H+] [A−] /[HA]
Concentration of HA, [HA] = 0.280 M,
Concentration of H+, [H+] = 4×10¯⁴ M
Concentration of A-, [A−] = 4×10¯⁴ M
Equilibrium constant (Ka) =
Ka = (4×10¯⁴ × 4×10¯⁴) / 0.280
Ka = 1.6×10¯⁷/ 0.280
Ka = 5.71×10¯⁷
Therefore, the equilibrium constant for the reaction is 5.71×10¯⁷
Finally, we shall determine the pka for the reaction as follow:
Equilibrium constant, Ka = 5.71×10¯⁷
pKa =?
pKa = – Log Ka
pKa = – Log 5.71×10¯⁷
pKa = 6.24
Therefore, the pka for the reaction is 6.24.
what is difference between paper and absorption chromatography
In partition chromatography, the stationary phase is in a liquid state. ... The difference between adsorption and partition chromatography is a separation of molecules occur based on the adsorption ability in adsorption chromatography while separation occurs based on the partition in partition chromatography
The density of liquid mercury is 13.6 g/mL. What is its density in units of lb/in3? (2.5 cm+1 in., 2.205 lbs= 1 kg., 1000 g =1 kg, 1 mL = 1 cm3).
Answer:
Density, [tex]\rho=0.49\ lb/in^3[/tex]
Explanation:
It is given that the density of liquid mercury is 13.6 g/mL. We need to convert the density into lb/in³.
We know that,
2.205 lbs= 1 kg
1 g = 0.0022 lb
1 mL = 0.0610 in³
[tex]13.6\ \dfrac{g}{mL}=13.6\times \dfrac{0.0022\ lb}{0.0610\ in^3}\\\\=0.49\ lb/in^3[/tex]
So, the density of liquid mercury is [tex]0.49\ lb/in^3[/tex].
Complete the following table for the three key subatomic particles.
Answer:
This question is incomplete without the table
Explanation:
The missing table is attached to this answer.
There are three subatomic particles found in an atom; protons, neutrons and electrons. The properties of the subatomic particles will be classified under the following subheadings (which are the empty columns/boxes in the attachment)
SYMBOL
The symbol of proton is "p⁺", the symbol of neutron is "n⁰" and the symbol of electron is "e⁻".
CHARGE
Looking at the symbol of the subatomic particles, one can guess the charge of each of the particles from the superscript.
Protons are positively charged, electrons are negatively charged while neutrons have no charge/electrically neutral.
The relative charge of proton is +1 while it's absolute charge is +1.60218 × 10⁻¹⁹
The charge of a proton was first determined by Ernest Rutherford using the gold-foil experiment
The relative charge of electron is -1 while it's absolute charge is -1.60218 × 10⁻¹⁹
The charge of an electron was first determined by R. Milikan using the oil-drop experiment
The relative charge and absolute charge of neutron is 0
The charge of a neutron was first determined by (or credited to) James Chadwick.
MASS
The relative mass (amu) of proton is 1.00727 while that of neutron is 1.00866. The relative mass (amu) of an electron is 0.00054858 while it's absolute mass (g) is 9.10939 × 10⁻²⁴.
The mass of an electron was first measured by J. J. Thomson.
The mass of a proton was first measured by (or credited to) Ernest Rutherford.
The mass of a neutron was first measured by James Chadwick.
LOCATION
The protons and neutrons are located inside the nucleus which is found in the centre of an atom while the electron(s) is/are found outside the nucleus but within the atom.
A chemical engineer must report the average volume of a certain pollutant produced by the plants under her supervision. Here are the data she has been given by each plant: What average volume should the chemical engineer report? Be sure your answer has the correct number of significant digits.
Answer:
[tex]V_{average}=15.34L[/tex]
Explanation:
Hello,
In this case, given the volumes of pollutants:
Macon 0.519 L
Ogiala 44.67 L
Pitt 0.826 L
The average he ought report is computed by adding them and subsequently dividing by three since there are three pollutants as shown below:
[tex]V_{average}=\frac{0.519L+44.67L+0.826L}{3} \\\\V_{average}=15.34L[/tex]
Regards.
Which compound has the highest boiling point? HF, HI, HBr, HCl, or F2?
Answer:
HF
Explanation:
This concept can be understood from the knowledge of Intermolecular forces of attraction.
Intermolecular bonds are Van der Waals forces which are weak forces of attraction joining non-polar and polar molecules together. They exist in the form of London Dispersion Forces and Dipole-dipole attraction.
An example of Dipole-dipole attraction is the hydrogen bond which is a unique dipole-dipole attraction between polar molecules in which a hydrogen atom is directly joined to a highly electronegative atom such as fluorine, oxygen, or nitrogen).
Molecules that possess the characteristics of hydrogen bonding have a higher boiling point. In the given question, only HF undergo hydrogen bond due to the electronegative effect of the fluorine element.
F2 occurs as a weak London dispersion force and it occurs between non-polar molecules.
Draw the Lewis structure for COCl2, including lone pairs.What is the molecular shape of COCl2? The C - Cl bond in COCl2 is polar or nonpolar? What is the Cl - C - Cl bond angle? The molecule COCl2 is polar or nonpolar?
Answer:
See explanation
Explanation:
COCl2 Contains two polar C- Cl bonds due to the electro negativity difference between carbon and chlorine.
There are 24 valence electrons in COCl2, the ideal bond angle is 120° based on the valence shell electron pair repulsion theory since the molecule trigonal planar. However, the double bond present compresses the bond angle to about 111°.
The dipoles in COCl2 do not cancel out hence the molecule is polar
The Lewis structure for COCl₂, including lone pairs is attached to the image below.
Carbon (C) has 4 valence electrons, oxygen (O) has 6 valence electrons, and chlorine (Cl) has 7 valence electrons.
In this structure, the oxygen atom is double-bonded to the carbon atom, and there is a single bond between the carbon atom and each chlorine atom. The oxygen atom has 2 lone pairs of electrons.
The molecular shape of COCl₂ is linear. The carbon atom is bonded to two chlorine atoms, and there are no lone pairs on the carbon atom. Therefore, the electron domain geometry is linear.
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which has the greatest percentage of oxygen? CO2, NO2,SO2 and MgO?
Answer:
CO₂
Explanation:
Please see attached picture for full solution.
* The masses of each atom can be found in the periodic table of elements
Calculate the energy change when an electron moves from n=5 to n=7. Explain/show work please.
Answer: E = 1.55 ⋅ 10 − 19 J
Explanation:
The energy transition will be equal to 1.55 ⋅ 10 − 1 J .
So, you know your energy levels to be n = 5 and n = 3. Rydberg's equation will allow you calculate the wavelength of the photon emitted by the electron during this transition
1 λ = R ⋅ ( 1 n 2 final − 1 n 2 initial ) , where λ - the wavelength of the emitted photon; R
- Rydberg's constant - 1.0974 ⋅ 10 7 m − 1 ; n final - the final energy level - in your case equal to 3; n initial - the initial energy level - in your case equal to 5. So, you've got all you need to solve for λ , so 1 λ =
1.0974 ⋅10 7 m − 1 ⋅ (.... −152
)
1
λ
=
0.07804
⋅
10
7
m
−
1
⇒
λ
=
1.28
⋅
10
−
6
m
Since
E
=
h
c
λ
, to calculate for the energy of this transition you'll have to multiply Rydberg's equation by
h
⋅
c
, where
h
- Planck's constant -
6.626
⋅
10
−
34
J
⋅
s
c
- the speed of light -
299,792,458 m/s
So, the transition energy for your particular transition (which is part of the Paschen Series) is
E
=
6.626
⋅
10
−
34
J
⋅
s
⋅
299,792,458
m/s
1.28
⋅
10
−
6
m
E
=
1.55
⋅
10
−
19
J
Chelsi has talked to her artist friends about how much money they earn each year from working in the arts. She
gathers these values from seven people: [$1,500; $6,700; $2,200; $8,100; $50,500; $12,000; $2,200).
What is the median of this data set?
$2,200
$6,700
$7,400
$11,900
Answer: 6,700
Explanation: took the test got it right :) (2020)
Answer:
B 6700
Explanation:
Choose the ingredients needed for nuclear fusion. Check all that apply. energy helium gas high temperatures hydrogen gas low pressure
answer:
high temperatures
hydrogen gas
Answer:
C and D
Explanation:
just did this on edg :)
Let’s take a look at sodium (Na) and chlorine (Cl). Draw what I am describing, and you will see it better. A sodium atom has how many protons? __________ A sodium atom has how many electrons? __________ How many electrons will go in the first shell? __________ How many in the second shell? __________ How many in the third? __________ Now draw this out on the diagram in Figure 2.1, and take a look at it, in particular the third (valence) shell. We know that Na requires eight electrons in its valence shell to become stable. But how many does it have? __________ So, to fill this shell, will it be easier for sodium to steal seven more electrons from another atom, or will it be easier for sodium to give up that one electron and get rid of that third shell? Sodium is simply going to give away that last electron. This means that it will lose an electron (negative charge) but will keep the same number of protons (positive charges). What will the sodium ion’s overall charge be now? _
Which of the following amino acid functional groups will influence the pKa of an amino acid residue the least if it is on an adjacent residue?A. -OH.B. -NH3.C. -CH3.D. -COOH.
Answer:
C. -CH3
Explanation:
The pKa (acid dissociation constant) of an amino acid residue is primarily influenced by the functional groups attached to the adjacent end of the amino acid chain. The acidity of a functional group depends on how electronegative the functional group is. In the given functional groups' list, the functional group with the least influence on the pKa of the amino acid is the alkyl substituent (-CH3), because they have the least electron-withdrawing capacity.
How is the le chatelier's principle used to ensure the reaction will go to completion?
Answer:
This done such that when a reaction is in equilibrium and disturb by and external force which would prevent its completion its adjust so as to offset that external force and still go on to completion
why is time plotted on the x axis and distance on the y axis?
Answer:
because time is independent and distance is dependent . time goes on if distance is not there but if distance is covered it is covered in certain time . that's why distance is taken on y axis while displacement on x axis
Round off the following numbers to the number of significant figures (sf) indicated.
a. 7.524 to 3 sf ______
b. 16.465 to 3 sf ______
c. 84.996 to 2 sf ______
d. 6.02502 to 2 sf ______
Answer:
a. 7.52
b. 16.5
c. 85
d. 6.03
Explanation:
significant number exempts 0 as a number which explains the last one. The two significant numbers there are 6 and 3
A child has a small rubber ball that is filled with water and glitter. When the ball is bounced the glitter spreads around the inside of the toy then settles back at the bottom. The mixture inside the toy would be considered which of the following?
Homogeneous
Solution
Heterogeneous
Colloid
Answer:
Heterogeneous
Explanation:
A heterogeneous mixture is a non-uniform composition in which particles of far larger size are suspended in a phase and can be easily separated from each other. In a heterogeneous mixture, the gravity pulls the suspended particles down out of solution.
The given example is a heterogeneous mixture in which glitter particles are suspended inside the toy and settles back at the bottom due to gravity. The glitter particles can also easily separated from the toy.
Hence, the correct answer is "Heterogeneous".
I need help with this question
Answer:
2.25×10¯³ mm.
Explanation:
From the question given above, we obtained the following information:
Diameter in micrometer = 2.25 μm
Diameter in millimetre (mm) =?
Next we shall convert 2.25 μm to metre (m). This can be obtained as follow:
1 μm = 1×10¯⁶ m
Therefore,
2.25 μm = 2.25 μm / 1 μm × 1×10¯⁶ m
2.25 μm = 2.25×10¯⁶ m
Finally, we shall convert 2.25×10¯⁶ m to millimetre (mm) as follow:
1 m = 1000 mm
Therefore,
2.25×10¯⁶ m = 2.25×10¯⁶ m /1 m × 1000 mm
2.25×10¯⁶ m = 2.25×10¯³ mm
Therefore, 2.25 μm is equivalent to 2.25×10¯³ mm.
A graduated cylinder is filled with 3 mL of water. A toy car that
weighs 29 g is gently placed in the cylinder and the water level
rises to 19 mL. What is the density of the toy car? Round to the
thousandths place.
Answer:
Density = 1.813 g/mLExplanation:
The density of a substance can be found by using the formula
[tex]Density = \frac{mass}{volume} [/tex]
From the question
mass of toy car = 29 g
Volume = New volume - original volume of water in cylinder
That's
volume = 19 - 3 = 16 mL
Substitute the values into the above formula and solve for the density
That's
[tex]Density = \frac{29}{16} \\ = 1.8125[/tex]
We have the final answer as
Density = 1.813 g/mL to the nearest thousandth
Hope this helps you
Answer:
1.813 g/mL
Explanation:
The density can be found with the following formula.
[tex]d= \frac{m}{v}[/tex]
where [tex]m[/tex] is the mass and [tex]v[/tex] is the volume.
We know the mass is 29 grams. We must find the volume.
The volume is equal to the volume of water that is displaced. Subtract the initial volume of water from the final volume.
⇒ final volume - initial volume of water
The initial volume of water is 3 mL and the final volume is 19 mL.
⇒ 19 mL - 3 mL
⇒ 16 mL
The volume of the toy car is 16 mL.
Now we know the mass and the volume.
[tex]m= 29g\\v=16mL[/tex]
Substitute the values into the formula.
[tex]d=\frac{m}{v}[/tex]
[tex]d=\frac{29g}{16mL}[/tex]
[tex]d=1.8125 g/mL[/tex]
Round to the nearest thousandth. The 5 in the ten thousandth place tells us to round the 2 to a 3.
[tex]d\approx1.813 g/mL[/tex]
The density of the toy car is about 1.813 grams per milliliter.
Which property of matter during a chemical change but does not change during a physical change
Answer:
The difference between physical change and chemical change is that chemical reaction is composition there is a change in the composition substances in question. In a physical change, there is a difference in the appearence, smell, or simple display of a sample matter
Explanation:
What rules can you use to tell how many protons, neutrons and electrons make up an atom or ion?
Answer:
Explanation:
This question appears incomplete, however
The number of protons of an element/atom (atomic number) can be determined by checking for the position of the element on the periodic table. This is because elements are arranged according to there atomic number on the periodic table.
The number of electrons of any element (of a neutral atom) is equal to the number of protons of the same element.
The number of neutrons of an element/atom is determined by subtracting the atomic number of the element from it's mass number. Hence, mass number is the addition of the atomic number and the number of neutrons.
Ions are charged particles that have the same number of protons and neutrons as there parent atoms. Hence, they have different number of electrons when compared to there specific parent/neutral atom.
A negatively charged atom has more electrons than it's original atom. For example, fluoride ion (F⁻) has 10 electrons while fluorine atom has 9 electrons (meaning fluoride ion has one more electron than it's parent fluorine). The increase is dependent on the number "attached" to the charge. A positively charged atom has less electrons than it's original atom. For example, calcium ion (Ca²⁺) has 18 electrons while calcium atom has 20 electrons (meaning the calcium ion has 2 electrons less than it's parent calcium atom). As said earlier, the decrease here is also dependent on the number "attached" to the charge.
The rule used for the determination of the protons, electrons, and neutrons has been the equal number of protons and electrons, while the number of the neutrons has been the difference in the atomic mass and the protons.
The atom has been the smallest particle that has comprised of electrons, protons, and neutrons as the subatomic particle. The neutrons and protons in the atoms have consisted within the nucleus. The electrons in the atom are revolving around the nucleus.
The atoms have been consisted of an equal number of protons and electrons, while the number of neutrons has been the difference in the atomic mass and the protons.
The ions have been formed with the loss or gain of the electrons by the atom in the terms of valence electrons to complete its octet.
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The first periodic table was organized according to atomic mass, but the current periodic table is arranged according to atomic number. why is the atomic number now the basis for the periodic table?
Answer:
It helps identify trends and group elements with similar properties.
Explanation:
Arranging the elements according to the atomic mass wouldn't help us have groups and periods with predictable properties that we can have when arranging it according to atomic number. Don't forget that isotopes have different masses.
Answer:
Not only on the basis of atomic number its acctually on the basis of their electronic configuration, chemicals properties and physical properties.
A block of aluminum occupies a volume of 13.8 mL and weighs 43.3 g.
What is its density? Give answer with one decimal.
Answer:
3.1g/mL
Explanation:
density = mass/volume
= 43.3/ 13.8
= 3.1g/mL