Answer:
B. an inner layer is needed because phospholipids always form bilayers.
Explanation:
Lipids are organic compounds which are not soluble in water but they are soluble in organic compounds. They are formed in body by combination of various molecules. The inner layer of phospholipids always form bilayers.
ionic bonds show which characteristics that arent seen in covalent bonds
Explain and describe how the photoelectric effect occurs on an atomic level in terms of protons, neutrons, and electrons
ANSWER:
Explaining the experiments on the photoelectric effect. How these experiments led to the idea if light behaving as a particle of energy called a photon.
Arrange the compounds in order of increasing entropy (S).
CH3OH(s)
CH3OH(l),
CH3OH(g),
CH3CH2OH(g)
CH3OH(s) > CH3OH (l) > CH3OH(g) > CH3CH2OH(g)
CH3OH(s) < CH3OH (l) < CH3OH(g) < CH3CH2OH(g)
3 Of 20
Answer:
CH3OH(s)<CH3OH(l)<CH3OH(g)<CH3CH2OH(g)
Explanation:
Entropy is defined as the degree of disorderliness of a system. The more orderly a system is, the more its entropy tends to zero.
Hence solid particles have the least entropy because solid particles do not translate. The entropy of liquid particles is greater than that of solid particles since liquid particles can translate. Gas particles have the highest entropy because gas particles move at a very high velocity owing to minimal intermolecular interaction.
Also, the heavier the molecules of a substance, the larger its molar entropy therefore, CH3CH2OH(g) exhibits the greatest entropy.
True or false one example of a chemical reaction is when H20 melts and changes state ice to liquid
Answer:
faulse
Explanation:
this is an example of a change in proporties
What type of reaction is shown below?
H202 + H2O + O2
Single replacement
Combustion
Synthesis
Decomposition
Answer:
Decomposition Reaction
Roundup, a herbicide manufactured by Monsanto, has the formula C3H8NO5P. How many moles of molecules are there in a 647.3-g sample of Roundup?
I got the answer 2.305 x 10^24 but for some reason it’s not working. Is it the wrong one?
Answer:
3.830177515 moles
Explanation:
You have :
647.3 g of RoundupMolar mass of Round up which is equal to 169 g.moland the formula: n=m/MTherefore: n=647.3/169
=3.830177515 moles
in which of the following type of colloid, the physical state of dispersed phase and dispersion medium is same?
Gel
Foam
Emulsion
Aerosol
Answer:
Emulsion
Explanation:
According to Oxford dictionary, a colloid is, ''a homogeneous non-crystalline substance consisting of large molecules or ultramicroscopic particles of one substance dispersed through a second substance. Colloids include gels, sols, and emulsions; the particles do not settle, and cannot be separated out by ordinary filtering or centrifuging like those in a suspension.''
An emulsion is a dispersion of a liquid in a liquid. This means that the the physical state of dispersed phase and dispersion medium is same.
Examples of emulsions include; Vinaigrette, homogenized milk and hair cream.
How many liters does 3 moles of Oxygen gas occupy at standard temperature and pressure
Answer: 3 moles of oxygen at STP will occupy a volume of 3×22. 4=67. 2 L.
PLEASE ANYONE HELP!!!
How does an increase in -CH2 groups in an organic chain affect the boiling point?
A. The boiling point increases as more -CH2 groups are added.
B. The boiling point increases up to 4 CH2 groups and then begins to decrease.
C. The boiling point is not affected by -CH2 groups, only by functional groups.
D. The boiling point decreases as more -CH2 groups are added.
Answer:
I believe it's a.
Explanation:
A se ion has a mass number of 77
and a charge of −2
. Determine the number of neutrons, protons, and electrons in this ion.
Answer:
1. Neutron number = 43
2. Proton number = 34
3. Electron number = 36
Explanation:
From the question given above, the following data were obtained:
Mass number = 77
Charge of ion = –2
1. Determination of the number of neutron.
Mass number of Se = 77
Atomic number = 34
Neutron number =?
NOTE: Atomic number = proton number
Mass number = Proton + Neutron
77 = 34 + Neutron
Collect like terms
77 – 34 = Neutron
Neutron number = 43
2. Determination of the proton number.
The atomic number of an element is simply defined as the number of protons in the atom of the element. Mathematically,
Atomic number = Proton number
Atomic number of Se = 34
Therefore, the proton number of Se²¯ is 34.
NOTE: The atomic number does not change be it atom, ion or molecule. It remains the same.
3. Determination of electron number.
Charge of ion = –2
Proton number = 34
Electron number =?
Proton – Electron = Charge
34 – Electron = –2
Rearrange
34 + 2 = Electron
36 = Electron
Electron number = 36
There are 43 neutrons, 34 protons, and 36 electrons in the given selenium ion with a (-2) charge.
Explanation:
Given:
A selenium ion with a mass number of 77 and a charge of (-2).
To find:
The number of neutrons, protons, and electrons in selenium ion
Solution:
Charge on the selenium ion = -2
The atomic number of selenium = 34
Number of protons = Atomic number
Number of protons in selenium atom = 34
Number of protons in selenium ion = 34
Number of electrons in selenium atom = 34
Number of electrons in selenium ion= 34+2 = 36
(anion is formed by gaining of electrons that is why adding two electrons )
The mass number of selenium = 77
Mass number = Number of protons + Number of neutrons
77 = 34 + Number of neutrons in selenium
Number of neutrons in selenium ion = 77 - 34 = 43
There are 43 neutrons, 34 protons, and 36 electrons in the given selenium ion with a (-2) charge.
Learn more about atoms and ions here:
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A hydrocarbon was found to contain 82.8% by mass of carbon. It has
an Mr of 58. Find the empirical and molecular formulas of this
compound.
Answer: C4H10
Explanation: [tex]\left \{ {{12x+y=58} \atop {\frac{12x}{58} =82,8%}} \right. \\[/tex]%
==> x=4, y=10 C4H10
Please answer ASAP!!
Cu+2 + 2e- ———> Cu E*= 0.52 V
Ag+1 + 1e- ———> Ag E*= 0.80 V
Using the two cell reduction potential shown for the corresponding reaction calculate the cell potential for a voltaic cell made from these two metals.
A. 1.32 V
B. -0.28 V
C.0.28 V
D. -1.32 V
Answer:
C.0.28 V
Explanation:
Using the standard cell potential we can find the standard cell potential for a voltaic cell as follows:
The most positive potential is the potential that will be more easily reduced. The other reaction will be the oxidized one. That means for the reactions:
Cu²⁺ + 2e⁻ → Cu E° = 0.52V
Ag⁺ + 1e⁻ → Ag E° = 0.80V
As the Cu will be oxidized:
Cu → Cu²⁺ + 2e⁻
The cell potential is:
E°Cell = E°cathode(reduced) - E°cathode(oxidized)
E°cell = 0.80V - (0.52V)
E°cell = 1.32V
Right answer is:
C.0.28 V
What type of nuclear decay is shown by the reaction below?
A. Alpha
B. Gamma
C. Beta
O D. Fission
Answer:
C. Beta
Explanation:
Select the correct answer.
A sample taken from a layer of mica in a canyon has 2.10 grams of potassium-40. A test reveals it to be 2.6 billion years old. How much
potassium-40 was in the sample originally if the half-life of potassium-40 is 1.3 billion years?
O A.
4.20 g
O B.
8.40 g
O C.
12.6 g
• D.
16.8 g
O E.
25.2 g
Answer:
8.36 g
Explanation:
From;
0.693/t1/2 = 2.303/t log (No/N)
t1/2 = half life of potassium-40
t = age of the sample
No= initial amount of the sample
N= amount of the sample at time t
Substituting values;
0.693/1.3 × 10^9 = 2.303/2.6 × 10^9 log (No/2.10)
5.33 × 10^-10 = 8.86 × 10^-10 log (No/2.10)
5.33 × 10^-10/8.86 × 10^-10 = log (No/2.10)
0.6 = log (No/2.10)
Antilog (0.6) = (No/2.10)
No = 2.10 × Antilog (0.6)
No= 8.36 g
PLLLLEEAASEEE HELLPP!!
What is the molarity of 150 g C6H12O6 per 0.50 L?
A. 300 mol/L
B. 75.0 mol/L
C. 1.68 mol/L
D. 0.833 mol/L
Answer: The correct option is C) 1.68 mol/L
Explanation:
Molarity is defined as the amount of solute expressed in the number of moles present per liter of solution. The units of molarity are mol/L. The formula used to calculate molarity:
[tex]\text{Molarity of solution}=\frac{\text{Given mass of solute}}{\text{Molar mass of solute}\times \text{Volume of solution (L)}}[/tex] .....(1)
Given values:
Given mass of [tex]C_6H_{12}O_6[/tex] = 150 g
Molar mass of [tex]C_6H_{12}O_6[/tex] = 180 g/mol
Volume of the solution = 0.50 L
Putting values in equation 1, we get:
[tex]\text{Molarity of solution}=\frac{150}{180\times 0.50}\\\\\text{Molarity of solution}=1.68M[/tex]
Hence, the correct option is C) 1.68 mol/L
304 cm x m and 67kg to gram please helpppp!!!!!!!!
Answer:
[tex]304cm = 3.04m \\ 67kg = 67000g[/tex]
Explanation:
[tex]100cm \: = 1m \\ 304cm = x \\ use \: \: cross \: multipication \\ 100x = 304 \\ \frac{100x}{100} = \frac{304}{100} \\ x = 3.04m[/tex]
-------------------------------------------------
[tex]1kg = 1000g \\ 67kg = x \\ \\ use \: cross \: \: multipication \\ 1x = 67 \times 1000 \\ x = 67000g[/tex]
Hope this helps
Have a nice day!
How many particles are in 54.5 g of aluminum? Show your work.
A. Convert the mass of aluminum to moles of aluminum. Molar mass of aluminum (Al) = 26.98 g/mol
B. Convert the moles of aluminum to particles of aluminum. There are 6.02 x 1023 particles/mol.
2 A certain gas of 25 g at 25°c and 0.65 atm occupies a volume of 23.52L Determine the molecule mass of the gas.
Answer:
[tex]{ \bf{PV= \frac{m}{M} RT}} \\ \\ { \tt{(0.65 \times 23.52) = \frac{25}{M} \times 0.081 \times (25 + 273)}} \\ \\ M = 39.5 \: g[/tex]
Please tell me the answer
Answer:
the pair of isotopes are b and e
the element with mass no of 19 is C
the element with atomic no 7is D
Explanation:
B and E are isotopes bcos they have the same atomic no, i.e no of protons. They bother have atomic no of 17 BUT have different mass no i.e sum of neutrons and protons.
(b)C is correct because the sum of the protons and neutrons is 19
(c) D because it has 7 protons
The body's reaction to a change in the environment is called a response.
Please select the best answer from the choices provided
OT
OF
What is a reaction rate
Answer:
Explanation:
A reaction rate is the measure of the change in concentration of the disappearance of reactants or the change in concentration of the appearance of products per unit time
Plz help..
How to name alcohols...
Answer:
Alcohols are usually named by the first procedure and are designated by an -ol suffix, as in ethanol, CH3CH2OH (note that a locator number is unnecessary on a two-carbon chain). On longer chains the location of the hydroxyl group determines chain numbering. For example: (CH3)2C=CHCH(OH)CH3 is 4-methyl-3-penten-2-ol.10
Explanation:
Answer:
ethanol formula :C2H5Oh
The half-reaction at the cathode in an electrochemical cell is given below. What other half-reaction would most likely occur at the anode to produce a spontaneous reaction?
Ni^2(aq)+2e-=Ni(s)
A. Cu(s)=Cu^2+(aq)+2e-
B. Zn(s)=Zn^2+(aq)+2e-
C. Mg^2+(aq)+2e-=Mg(s)
D. Ni(s)=Ni^2+(aq)+2e-
The half-reaction is Zn → Zn⁺² + 2e⁻ which is most likely occur at the anode to produce a spontaneous reaction.
Hence, option (B) is correct answer.
What is Spontaneous Reaction ?A reaction which occurs without the intervention of outside is called Spontaneous reaction. The reaction is Spontaneous when the Δ G < 0 and [tex]E^{\circ}_{\text{cell}}[/tex] > 0.
What is Cathode and Anode ?Cathode where the reduction occurs. Anode where the oxidation take place.
Cathode: Ni⁺² + 2e⁻ → Ni
Anode: Zn → Zn⁺² + 2e⁻
______________________
Zn + Ni⁺² → Zn⁺² + Ni
The above reaction is spontaneous reaction.
Thus, from the above conclusion we can say that half-reaction is Zn → Zn⁺² + 2e⁻ which is most likely occur at the anode to produce a spontaneous reaction.
Hence, option (B) is correct answer.
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Iron pieces can be separated from sand using
Answer:
A Magnet or Magnetic Filtration
Answer:
Magnetic Filtration
Explanation:
That is the answer
Hi Everyone ✌
hope u all r doin well
Pls Answer
What happens when dilute sulphuric acid is poured on a copper plate ?
Answer:
No observable change.
Explanation:
Copper renders dilute sulphuric acid passive, no reaction.
H2SO4+Cu-->CuSO4+H2
Explanation:
THIS IS THE CORRECT ANSWER
Which of these statements is true about heat?
Answer:
Explanation:
what are the statments i can't help till i have the posable answers
Equal mases of ethane and hydrogen are mixed in an empty container at 25 degree celcius.The fraction of the total pressure exerted by hydrogen is
Answer:
15/16
Explanation:
We need to find the number of moles of hydrogen and number of moles of ethane present.
Since we have the same mass, m for both substances, the number of moles of hydrogen, n = m/M where M = molar mass of hydrogen molecule
Since hydrogen is H₂, M = 2 × 1 g/mol = 2 × 1 g/mol = 2 mol.
n = m/M
n = m/2
Also, number of moles of ethane, n' = m/M' where M' = molar mass of ethane.
Since ethane is C₂H₆, M' = 2 × 12 g/mol + 6 × 1 g/mol = 24 g/mol + 6 g/mol = 30 g/mol
n' = m/M'
n' = m/30
The total number of moles of gas present is thus n" = n + n' = m/2 + m/30 = (15m + m)/30 = 16m/30
The mole fraction of hydrogen is thus number of moles of hydrogen/total number of moles = n/n" = m/2 ÷ 16m/30 = m/2 × 30/16m = 15/16
Also, since the partial pressure due to hydrogen, P = mole fraction × total pressure, P'
P/P' = mole fraction = 15/16
So, The fraction of the total pressure exerted by hydrogen is 15/16
Which element has a smaller ionic radius than magnesium (Mg)?
A) Rb
B) Al
C) Ca
D) Na
Answer:
Na has atomic number 11
which is less than magnesium has atomic number 12
ANSWER IS D
Explanation:
aluminum or Al is atomic 13 and Ca or calcium is atomic number 20 and rubidium or Rb is atomic number 37
what are the difference between ionic bond and covalent bond?
Which is stronger?
QUËSTIONS :- what are the difference between ionic bond and covalent bond?
IONIC BONDS :- THEY R BONDS WHICH R FORMED DUE TO THE COMPLETE TRANSFER OF ELECTRONS BETWEEN TWO ATOMS
COVALENT BONDS :- THEY R THE BONDS WHICH R FORMED DUE TO INCOMPLETE TRANSFER OF ELECTRONS BETWEEN TWO ATOMS
IONIC BONDS R MORE STRONGER.
Explanation:
Ionic bond is much stronger than covalent bond because it involves complete transfer of electrons because of which there is formation of cation and anion and there exist huge electrostatic forces of attraction. They also have high melting and boiling point which proves that the ionic bond is very strong.
Differences between ionic bond and covalent bond :
Ionic Bonds. Covalent Bonds
Polarity :High. Low
Shape : No definite shape. Definite shape
Melting Point :High Low
Boiling Point: High Low
If oxygen has 6 valence electrons how many it would like to gain to have full valence shell? And what charge will it give to oxygen ion?
Answer:
Gain 2, and become negatively charged
Explanation:
A full valence shell, thus stablilized, has 8 electrons, and so it would need two more, and when atoms gain electrons, they become negatively charged because there are now more electrons than protons (and so, when they lose electrons, they become positively charged). Hope this helps! :)
