Answer:
I found on internet may be it helps
Explanation:
Here, we provide a general review of recent studies into the genetic basis of human brain evolution. The insights gleaned from these studies can be broadly divided into three categories: (i) positive selection on protein-coding regions of the genome that lead to changes in the sequences of existing proteins; (ii) duplication and deletion of genes; and (iii) evolutionary changes in non-coding regions of the genome, especially those in cis-regulatory sequences that lead to altered gene expression .
Which shows the correct order of steps in the formation of coal?
Layers of dead plants pile up - plant matter is buried by rocks and dirt - dead plants fall in swamp - plant matter is
compressed and is exposed to heat - coal forms
Plant matter is compressed and is exposed to heat - dead plants fall in swamp - layers of dead plants pile up - plant
matter is buried by rocks and dirt - coal forms
Plant matter is buried by rocks and dirt - dead plants fall in swamp - layers of dead plants pile up - plant matter is
compressed and is exposed to heat - coal forms
Dead plants fall in swamp - layers of dead plants pile up - plant matter is buried by rocks and dirt - plant matter is
compressed and is exposed to heat - coal forms
Answer:
it is Dead plants fall in swamp, Layers of dead plants pile up, Plant matter is buried by rocks and dirt, Plant matter is compressed and is exposed to heat, and Coal forms.
if iam right please make this into brainlest
What is the shape of the H2S molecule?
bent
pyramidal
linear
trigonal planar
Answer:
The answer is bent
Answer:
The molecule is bent
Explanation:
Which term should replace the question mark?
Answer:
Can you explain a little bit more?
Explanation:
Based on the Lewis/electron dot representation
of the two atoms, predict the ratio of metal
cationic (+) atom to nonmetal anionic (-) atom in the compound
Answer:
A. 1:3
Explanation:
If we look at the ions shown in the image attached to the question, we will notice that we have aluminum (Al^3+), a trivalent ion combining with the iodide ion (I^-).
Aluminum can easily give out its three outermost electrons to three atoms of iodine. If aluminum gives out its three electrons, it achieves the stable octet structure. Iodine atoms have seven electrons in their outermost shell. They only need one more electrons to complete their octet. This one electron can be gotten by the combination of three iodine atoms with one atom of aluminum. One electron each is transferred from the aluminum atom to each iodine atom to form AlI3 with a ratio of 1:3.
Lewis dot structure is a diagrammatic representation of valence electrons in an atom of a molecule.
The ratio of the cations to anions in the given compound is 1:3.
In the given figure, Aluminum has 3 electrons, which can be donated to iodine. Aluminum has atomic number 13, this means that if the element donates three electrons then it will attain a stable electronic configuration.
In the Iodine atom, each iodine needs only one electron to complete its octet. Thus, three atoms of iodine will be required to gain electrons from aluminum.
Thus, the ratio cation to the anion is 1:3.
To know more about lewis dot structure, refer to the following link:
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Molybdenum metal requires a photon with a minimum frequency of 1.09x1015s-1before it can emit an electron via the photoelectric effect.
a) What is the minimum energy needed to eject an electron?
b)What wavelength of radiation (in nm) will provide a photon of this energy?
c)How many electrons can be freed by a burst of radiation whose total energy is 1.00 μJ, assuming one photon causes one electron to be freed? (μ= micro = 10-6)
d) If molybdenum is irradiated with light of 122nm, what is the maximum kinetic energy of the emitted electrons?
Answer:
a) 7.22 × 10⁻¹⁹ J; b) 275 nm; c) 1.38× 10¹² electrons; d) 9.1 × 10⁻¹⁹ J
Explanation:
a) Minimum energy to eject photon
E = hf = 6.626× 10⁻³⁴ J·s × 1.09 × 10¹⁵ s⁻¹ = 7.22 × 10⁻¹⁹ J
b) Wavelength required
fλ = c
[tex]\lambda = \dfrac{c}{f } = \dfrac{2.998 \times 10^{8}\text{ m/s}}{1.09 \times 10^{15}\text{/s}} = 2.75 \times 10^{-7} \text{ m} = \textbf{275 nm}[/tex]
c) Electrons required
[tex]\text{No. of electrons} = 1.00 \times 10^{-6}\text{ J} \times \dfrac{\text{1 electron}}{7.22 \times 10^{-19}\text{ J}} = 1.38 \times 10^{12}\text{ electrons}[/tex]
d) Kinetic energy of electrons
a) Energy of photon
[tex]E = hf = \dfrac{\text{hc}}{\lambda} = \dfrac{6.626 \times 10^{-34} \text{ J$\cdot$ s}\times 2.998 \times 10^{8} \text{ m/s}}{122 \times 10^{-9}\text{ m}}= 1.63 \times 10^{-18} \text{ J}[/tex]
b) Maximum kinetic energy
The equation for the photoelectric effect is
hf = φ + KE, where
φ = the work function of the metal — the minimum energy needed to eject an electron
KE = hf - φ = 1.63× 10⁻¹⁸ J - 7.22× 10⁻¹⁹ J = 9.1 × 10⁻¹⁹ J
a. The energy of molybdenum to eject electron has been [tex]\rm \bold{7.22\;\times\;10^{-19}}\;J[/tex].
b. The wavelength of the radiation has been 275 nm.
c. The number of electrons present in [tex]\rm 1\;\mu J[/tex] energy has been [tex]\rm \bold{1.38\;\times\;10^1^2}[/tex].
d. The kinetic energy of the emitted electrons as been [tex]\rm \bold{9.1\;\times\;10^-^1^9\;J}[/tex].
The metal emits the energy when it returns from the excited state to ground state.
a. The energy (E) to eject electron has been given by:
[tex]E=h\nu[/tex]
Where, the value of constant, [tex]h=6.626\;\times\;10^{-34}\;\rm J.s[/tex]
The value of frequency has been given, [tex]\nu=\rm 1.09\;\times\;10^{15}\;s^{-1}[/tex]
Substituting the values for energy:
[tex]E=6.626\;\times\;10^{-34}\;\times\;1.09\;\times\;10^{15} \rm J\\\textit E=7.22\;\times\;10^{-19}\;J[/tex]
The energy of molybdenum to eject electron has been [tex]\rm \bold{7.22\;\times\;10^{-19}}\;J[/tex].
b. The wavelength ([tex]\lambda[/tex]) of the radiation has been given by:
[tex]\lambda=\dfrac{c}{\nu}[/tex]
Where, the speed of light, [tex]c=3\;\times\;\rm m/s[/tex]
The frequency has been given as, [tex]\nu=1.09\;\times\;10^{15}\;\rm s^-^1[/tex].
Substituting the values for wavelength:
[tex]\lambda=\dfrac{3\;\times\;10^8}{1.09\;\times\;10^{15}}\;\rm m\\ \lambda=2.75\;\times\;10^-^7\;m\\\lambda=275\;nm[/tex]
The wavelength of the radiation has been 275 nm.
c. The electrons ([tex]e^-[/tex]) burst out can be given as:
[tex]e^-=\dfrac{E}{E'}[/tex]
Where, the energy of radiations, [tex]E=1\;\times\;10^{-6}\;\rm J[/tex]
The energy of each electron has been calculated as, [tex]E'=7.22\;\times\;10^{-19}\;\rm J[/tex]
Substituting the values for number of electrons:
[tex]e^-=\dfrac{1\;\times\;10^-^6}{7.22\;\times\;10^-^1^9} \\e^-=1.38\;\times\;10^1^2[/tex]
The number of electrons present in [tex]\rm 1\;\mu J[/tex] energy has been [tex]\rm \bold{1.38\;\times\;10^1^2}[/tex].
d. The maximum kinetic energy (K.E.) of the radiation has been given as:
[tex]K.E.=\dfrac{hc}{\lambda} -E^'[/tex]
Where, the value of constant, [tex]h=6.626\;\times\;10^{-34}\;\rm J.s[/tex]
The speed of light, [tex]c=3\;\times\;\rm m/s[/tex]
The wavelength of the radiation, [tex]\lambda=122\;\times\;10^-^9\;\rm m[/tex]
Energy of each electron, [tex]E'=7.22\;\times\;10^{-19}\;\rm J[/tex]
Substituting the values, for kinetic energy:
[tex]K.E.=\dfrac{6.626\;\times\;10^{-34}\;\times\;3.0\;\times\;10^8}{122\;\times\;10^-^9}\;-\;7.22\;\times\;10^-^1^9\;\rm J \\\textit {K.E.}=9.1\;\times\;10^{-19}\;J[/tex]
The kinetic energy of the emitted electrons as been [tex]\rm \bold{9.1\;\times\;10^-^1^9\;J}[/tex].
For more information about photoelectric effect, refer to the link:
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Cracking of octane please help! Show the chemical formula and the diagrams
Answer:
Fuels made from oil mixtures containing large hydrocarbon molecules are not efficient as they do not flow easily and are difficult to ignite. Crude oil often contains too many large hydrocarbon molecules and not enough small hydrocarbon molecules to meet demand. This is where cracking comes in
Explanation:
Use the balanced equation below to answer the question that follows
6 CO2 + 6H2O - CH206 +60,
How many moles of water are needed to produce 4 moles of CH420?-
a.4
b. 6
c. 10
d. 24
Ammonia (NH3) Is base.
How best do you describe Ammonia when dissolved in water
B. Ammonia forms a neutral solution.
C. Ammonia forms a buffered solution.
d. Ammonia acts as base because has OH- and makes water accepts hydrogen.
Answer:
Ammonia accepts a proton from water
Explanation:
Let us quickly remind ourselves of the Brownstead-Lowry definition of an acid. According to Brownstd-Lowry, an acid is any substance that donates hydrogen ions while a base is any substance that accepts hydrogen ions. The hydrogen ion is also known as a proton.
If we look at the behaviour of ammonia in water;
NH3(g) + H2O(l) ----> NH4^+(aq) + OH^-(aq)
We can easily see that ammonia accepts a proton from water (this makes it a Brownstd-Lowry base) and the hydroxide ion is formed in the process. Water functions as the proton donor here.
What is the percent by mass in a solution with 10.0 grams of solute and 25.0 grams of solvent?
Answer:
Percent by mass of solute is (10/35) x 100 = 28.57%
Percent by mass of solvent is (25/35) x 100 = 71.43%
Explanation:
10.0 grams of solute
25.0 grams of solvent
Total Mass = 35 grams
percent by mass = (Mass A / Total Mass) x 100
Percent by mass of solute is (10/35) x 100 = 28.57%
Percent by mass of solvent is (25/35) x 100 = 71.43%
How many moles of zinch oxide can be produced from 275 of zinc?
Answer:
[tex]\large \boxed{\text{4.21 mol}}[/tex]
Explanation:
We must do the conversions :
mass of Zn ⟶ moles of Zn ⟶ moles of ZnO
We will need a chemical equation with masses and molar masses, so, let's gather all the information in one place.
Mᵣ: 65.38
Zn + … ⟶ ZnO + …
m/g: 275
(a) Moles of Zn
[tex]\text{Moles of Zn} = \text{275 g Zn}\times \dfrac{\text{1 mol Zn}}{\text{65.38 g Zn}} = \text{4.206 mol Zn}[/tex]
(b) Moles of ZnO
The molar ratio is 1 mol ZnO:1 mol Zn
[tex]\text{Moles of ZnO} =\text{4.206 mol Zn} \times \dfrac{\text{1 mol ZnO}}{\text{1 mol Zn}} = \text{4.21 mol ZnO}\\\\\text{The reaction produces $\large \boxed{\textbf{4.21 mol}}$ of ZnO}[/tex]
At what temperature does the solid start meltin
-20°C
0°C
20"
80°C
Answer:
0 C.
Explanation:
What happens to the motion of the atoms in a spoon after is placed in hot soup?
Answer:
they move faster
Explanation:
Answer:
They move faster.
The type of energy transferred by a wave in a medium is kinetic energy.
Answer:
The statement is true.
Explanation:
The different means by which the energy is transferred is commonly termed to be 'wave'.
Wave refers to the disturbance transmission from a specific point to another. Different sources are involved in this transmission. The vibration of particles helps in the flow of energy from one medium to another. Vibration leads to the formation of kinetic energy flowing from one medium to another.
plz help i need the answer ASAP If 6.20 cm3 of a 6.75 M (M = mol/dm3) solution are diluted to 85.6 cm3 with water, what is the concentration of the final solution?
A. 6.75 (6.20/85.6)
B. 6.75 (8.56/6.20)
C. 6.75 (6200/85.6)
D. 6.75 (85.6/6200)
a) A
b) B
c) C
d) D
Answer:
Option A. 6.75 (6.20/85.6)
Explanation:
The following data were obtained from the question:
Initial volume (V1) = 6.2cm³
Initial concentration (C1) = 6.75M
Final volume (V2) = 85.6cm³
Final concentration (C2) =.?
The final concentration can be obtained by using the dilution formula as show below:
C1V1 = C2V2
6.75 x 6.2 = C2 x 85.6
Divide both side by 85.6
C2 = (6.75 x 6.2) /85.6
C2 = 6.75 (6.2 / 85.6).
CH3CH2CHCH2 + HCl in iupac
Answer:
But-1-ene and Hydrochloric acid
Explanation:
CH3CH2CHCH2
H H H
H - C- C - C = C
H H H
C - Carbon
H - Hydrogen
But-1-ene
H - Cl
H - Hydrogen = 1+ = Hard Acid
Cl - Chlorine = 1- = Hard Base
Hydrochloric acid
Carbon-14 is a common isotope of the element. How many electrons
does it contain?
O 14
O 12
O 8
O 6
) carbon + oxygen = _____________
E) calcium carbonate = ______________ + _________________
F) carbon + hydrogen = ____________
G) carbon + hydrogen + oxygen = ______________
H) water = ___________ + ___________
I) Iron + sulphur = _______________
J) magnesium + oxygen = ________________
M) magnesium oxide + water = ___________________
O) carbon monoxide + oxygen = ______________
Answer:
d)carbon(iv)oxide/carbon(ii)oxide
e)Calcium,carbon,oxygen
f)carnonhydride
g)Carbonhydrate
h)hydrogen+oxygen
I)Iron sulphide
j)Magnesiumoxide
m)magnesium hydroxide+hydrogen gas
d)carbon dioxide
hey so for science class im making a brochure for a vacation to mars.
can someone give me a good name and theme for a hotel that would be on mars?
Answer:
The name of the hotel can be the Red dust hotel. And the theme could red and rocky
Explanation:
In 450 BCE, Greek philosopher Democritus first thought of the existence
of tiny particles that compose everything around us. He named them
'atomos', meaning
A. Invisible
B. Particle
C. Indivisible
D. None of these
Reset Selection
Answer:
A. Invisible
Explanation:
Answer: Indivisible
Explanation: There was a brilliant philosopher named Democritus, and he proposed the Greek word atomos, which means uncuttable.
Synonyms for uncuttable are as follows:
Joined, inseparable, Indivisible, unbreakable, irreducible, impenetrable, unalterable, indissoluble, unified, permanent, immutable and unchangeable.
Why other answers are wrong:
I simply believe the other user may have had a minor typo which caused such confusion. Who knew one letter could effect an answer that much XD
The Sunhawk, a car built by students at SUNY New Paltz, prompted Forbes Magazine to ask “Is The $250,000 Sunhawk theSolar Car of the Future?” These cars show the most advanced solar technology and vehicle construction.There are trade-offs involved in the use of solar powered cars. What one advantage of owning a solar car?
Answer:
The potential of energy availability at all locations where there is Sunlight
Explanation:
One advantage in owning a solar car is the potential of energy availability
The solar car source of energy is from the Sun which is readily available during the daytime where there is a clear sky. The energy from sunlight is converted to to electrical energy by the photovoltaic cells on solar panels installed on the roof area of solar powered cars
The energy from the Sunlight is a form of renewable energy and therefore allows for better stability as well as the possibility of reuse of the energy
There are no emissions from the use of solar cars including noise, making the solar car very environmentally friendly.
A bobsled has a momentum of 4000 0 kg* m/s to the south. Friction on the track reduces its momentum to 500 kg* m/s to the south. What impulse is applied to the bobsled by the friction?
A. 6500 kg* m/s north
OB. 1500 kg* m/s south O
C. 6500 kg* m/s south
O 1500 kg* m/s north
Answer: 1500 kg•m/s north
Explanation:
A PE X
How do the HOX genes in the paddlefish match the HOX genes in human
Answer:
Hox are transcription factors that are evolutionarily conserved across bilaterians and, therefore, they share sequence homology between paddlefish and humans .
Explanation:
The Hox genes represent a family of homeodomain transcription factors that play roles in the development of the axial and appendicular skeleton, being therefore critical during embryonic development. In this case, the human Hox genes are homologous to homeobox genes found in the paddlefish. These genes have a DNA-binding domain of 60 amino acids which is evolutionarily conserved in bilaterian species including paddlefish and human species.
Plz help me with this question
State a condition required for a substitution reaction to occur
Explanation:
substitution reaction (also known as single displacement reaction or single substitution reaction) in a chemical reaction during which one functional group in chemical compound is replaced by an other functional group. a good example of a substitution reaction is halogenation .
A saturated solution of sulfur dioxide is prepared by dissolving SO2(g) in 100. g of water at 10.°C and standard pressure.
Determine the mass of SO2 in this solution.
A.) 15g to 18g
B.) 40g to 43g
C.) 53g to 56g
D.) 6g to 8g
Answer:
The correct option is;
A.) 15 g to 18 g
Explanation:
The solubility of sulfur dioxide at room temperature = 94 g/L of water forming sulfurous acid as follows;
SO₂ + H₂O ⇄ HSO₃⁻ + H⁺
Which is a partial reversibly association with water molecules
Whereby 1 liter of water weighs 1 kg
9.4 gram of SO₂ will dissolve in 100 g of water at room temperature of 23 to 24°C
The solubility increases as the temperature reduces therefore as shown from the sulfur dioxide solubility chart we have;
At 10°C the solubility of SO₂ (g) is midway between 150 g to 200 g per kg of water
Therefore;
The solubility of SO₂ (g) is between 15 g to 18 g per 100 of water.
The mass of SO2 in the given solution should be an option a 15g to 18g.
Calculation of the mass:Since the solubility of sulfur dioxide at room temperature = 94 g/L of water forming sulfurous acid likewise:
SO₂ + H₂O ⇄ HSO₃⁻ + H⁺
This represents the partial reversibly association along with water molecules
Here 1 liter of water weighs 1 kg
So we can say that
9.4 gram of SO₂ will dissolve in 100 g of water at room temperature of 23 to 24°C
Due to this, there is an increase in solubility this result in decrease in the temperature
Also, At 10°C the solubility of SO₂ (g) is midway between 150 g to 200 g per kg of water
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The type of radioactive decay in which the mass number and atomic number remain unchanged is (2 points) Select one: a. beta radiation. b. alpha radiation. c. positron radiation. d. gamma radiation.
Answer:
d.
Explanation:
a. beta radiation - electrons that have negative charge, and when they leave a nucleus , the charge or atomic number of the nucleus will change.
b. Alpha radiation - nuclei of He, atomic number and mass number will be changed.
c. positron radiation - positrons are similar to electrons but have positive charge, so , the charge or atomic number of the nucleus will change.
d. gamma radiation is electromagnetic waves, does not have charge and mass.
Answer:
the answer is d. gamma radiation
Explanation:
Which type of reaction is described by the following equation Na2O (s) + 2CO2 (g) + H2) (g) Produces 2 NaHCO3 (s)
Answer:
If the reaction is going from left to right it would be synthesis, if going right to left it would be decomposition.
Explanation:
Na2O (s) + 2CO2 (g) + H2O (g) = 2 NaHCO3 (s)
Left Side
Na = 2
O = 6
C = 2
H = 2
Right Side
Na = 2
O = 6
C = 2
H = 2
Ok so is balanced already, though initial equation in question had an error in regards to the left hand side the ) should have been an O.
Hmm
Na2O (s) + 2CO2 (g) + H2O (g) = 2 NaHCO3 (s)
If it was going from right to left would be decomposition
But going from left to right it would be synthesis
pleaseeeeee yelp!!! 100 points
Question 10 Multiple Choice Worth 3 points)
(05.03 MC)
A glass of juice at 20°C was kept in the open. After 30 minutes, the temperature of the juice remained the same. Which statement is correct?
The temperature of the surrounding air was greater than 20 °C.
The temperature of the surrounding air was less than 20 °C.
The temperature of the juice was equal to the temperature of the surrounding air.
The temperature of the juice was less than the final temperature of the surrounding air.
Answer:
The answer would be B the temperature of the juice was the temperature of the surrounding air...trust me lolllllllllllllllll
I’ve gotten the answer as x=.478 but when plugging back in, .46/.478 ≠ .22. Help please
Answer:
15. 2.66 moles .
16. 2.09L.
Explanation:
Molarity of a solution is simply defined as the mole of solute per unit litre of the solvent. Mathematically, it is represented as:
Molarity = mole /Volume.
With the above formula, let us answer the questions given above
15. Data obtained from the question include the following:
Volume of solution = 1.4L
Molarity = 1.9M
Mole of solute =.?
Molarity = mole /Volume
1.9 = mole / 1.4
Cross multiply
Mole = 1.9 x 1.4
Mole = 2.66 moles
Therefore, the mole of the solute present in the solution is 2.66 moles.
16. Data obtained from the question include the following:
Mole of solute = 0.46 mole
Molarity = 0.22M
Volume of solvent (water) =.?
Molarity = mole /Volume
0.22 = 0.46/Volume
Cross multiply
0.22 x Volume = 0.46
Divide both side 0.22
Volume = 0.46/0.22
Volume = 2.09L
Therefore, 2.09L of water is required.
For the reaction NH4Cl (s)→NH3 (g) + HCl (g) at 25°C, ΔH = 176 kJ/moland ΔS = 0.285 kJ/(mol - K).
What is the ΔG, and will this reaction be spontaneous in the forward direction?
169 kJ/mol; no
-91 kJ/mol; yes
91 kJ/mol; no
91 kJ/mol; yes
please answer quick
Answer:
91kj/mol;no
Explanation:
Took this before I gotchu.
What is the ΔG, and will this reaction be spontaneous in the forward direction? 91 kJ/mol; no
What does ΔG mean in chemistry?
Gibbs is a free number of power converters
In the active and frequent use of the Gibbs free energy change equation, ΔG is calculated from the fixed values that scientists can measure: the enthalpy and entropy changes of the reaction, and the temperature at which the reaction occurs.
What is Delta G measured in?
joules
measured in joules in SI) is the maximum amount of non-expansion work that can be extracted from a closed system (one that can exchange heat and work with its surroundings, but no matter) at fixed temperature and pressure. This maximum can be attained only in a completely reversible process.
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