Answer:
2 pairs (4 electrons)
Explanation:
In a molecule of oxygen there are 2 oxygen atoms. There are 6 electrons in the outer shells of oxygen atoms. When 2 oxygen atoms form a covalent bond they share their electrons. In a diagram this would be represented by the overlap of the two circles representing the outer shells of both oxygen atoms. If each oxygen atom 'puts forward' 2 electrons into the centre, then 4 will be shared overall for each atom, making both atoms have full outer shells of 8 electrons each. 4 electrons make 2 pairs, hence the answer.
difference between vegetative and reproductive part
Answer:
The vegetative parts includes the roots, stems,leaves and the reproductive parts include flowers. ... The vegetative parts can reproduce new plants by the process of vegetative propagation but the reproductive parts cannot produce new plants directly instead they produce precursor of new plants that are seeds or fruits.
A student prepares a aqueous solution of butanoic acid . Calculate the fraction of butanoic acid that is in the dissociated form in his solution. Express your answer as a percentage. You will probably find some useful data in the ALEKS Data resource.
Answer:
15.4%
Explanation:
If Ka = 0.54 mM = 1.51x10⁻⁵
Then;
C₄H₈O₂ --------> C₄H₇O₂⁻ + H⁺
I 0.54x10⁻³ 0 0
E 0.54x10⁻³(1-x) 0.54x10⁻³x 0.54x10⁻³x
Recall that x is the percentage degree of dissociation
From the ICE table;
Ka = [C₄H₇O₂⁻] [ H⁺]/[C₄H₈O₂]
1.51x10⁻⁵=(0.54x10⁻³x) (0.54x10⁻³x)/ 0.54x10⁻³(1-x)
1.51x10⁻⁵ = 0.54x10⁻³x^2/1-x
1.51x10⁻⁵(1-x) = 0.54x10⁻³x^2
1.51x10⁻⁵ - 1.51x10⁻⁵x = 0.54x10⁻³x^2
Hence;
0.54x10⁻³x^2 + 1.51x10⁻⁵x - 1.51x10⁻⁵=0
x^2 + 0.028x - 0.028 = 0
Solving the quadratic equation here;
x = 0.154 or −0.182
Ignoring the negative result, x = 0.154
Hence, fraction of butanoic acid that is in the dissociated form in this solution = 15.4%
g Consider (12.5 A) micro-grams of a radioactive isotope with a mass number of (78 B) and a half-life of (32.6 C) million years. If energy released in each decay is 32.6 keV, determine the total energy released in joules (J) in 1 (one) year. Give your answer with three significant figures.
Answer:
Energy released = 18.985 J
Explanation:
The exponential decay of radioactive substance is given by -
N(t) = N₀ [tex]e^{-kt}[/tex]
where
N₀ = initial quantity
k = decay constant
Half life, [tex]t_{1/2} = \frac{ln 2}{k}[/tex]
⇒[tex]k = \frac{ln 2}{t_{1/2} }[/tex]
Given,
N₀ = 12.5 + 3 = 15.5 × 10⁻⁶ gm
[tex]t_{1/2}[/tex] = 32.6 + 18 = 50.6 × 10⁶ years
So,
[tex]k = \frac{ln 2}{50.6 * 10^{6} }[/tex] = 1.361 × 10⁻⁸ year⁻¹
Now,
N(1) = 15.5 × 10⁻⁶ [tex]e^{-1.361*10^{-8} *1}[/tex]
= 15.49999978904
Now,
Substance decayed = N₀ - N(t)
= 15.5 × 10⁻⁶ - 15.49999978904 × 10⁻⁶
= 21.095 × 10⁻¹⁷ kg
⇒Δm = 21.095 × 10⁻¹⁷ kg
So,
Energy released = Δmc²
= 21.095 × 10⁻¹⁷ × 3 ×10⁸ × 3 × 10⁸
= 189.855 ×10⁻¹
= 18.985 J
⇒Energy released = 18.985 J
Question 6 (1 point)
"When two or more objects collide, there will be the same amount of momentum before the collision as after" is
a) Momentum Rule
b) Law of Collisions
c) Law of Conservation of Momentum
d) The Law of Before and After
where do the sun rays hit Earth's surface nearly at right angles
Answer:
The Sun Ray's hit earths surface at Earths Equator
The acid ionization equilibrium for the weak acid HF is represented by the equation above. To prepare a buffer with a pH=3.50, a student needs to mix 250.mL of 0.100MHF and 250.mL of 0.100MKF. If the student mistakenly mixes 250.mL of 0.0500MHF and 250.mL of 0.0500MKF, which of the following is the result of this error?
The buffer will have a lower capacity because of the smaller number of moles of HF and F− available to react if an acid or base is added.
The buffer will have a lower capacity because of the smaller number of moles of H F and F with a negative 1 charge available to react if an acid or base is added.
The buffer will have a lower capacity because the smaller amount of HF and F− will lower the pH of the buffer, and buffers of lower pH have a lower buffer capacity.
The buffer will have a lower capacity because the smaller amount of H F and F with a negative 1 charge will lower the p H of the buffer, and buffers of lower p H have a lower buffer capacity.
The buffer will have a higher capacity because a larger proportion of HF and F− will ionize at lower concentrations, resulting in the neutralization of any added acid or base.
The buffer will have a higher capacity because a larger proportion of H F and F with a negative 1 charge will ionize at lower concentrations, resulting in the neutralization of any added acid or base.
The buffer will have the same capacity because the large volume of the buffer solution dilutes any added acid or base
Answer:
4
Explanation:
From the options provided the result of the error is ( A ) ; The buffer will have a lower capacity because of the smaller number of moles of HF and F⁻ available to react if an acid or base is added.
Considering the acid ionization equilibrium for the weak acid HF.
A buffer solution is a solution that its PH value remains unchanged when a small amount of acid or base to added to the solution, therefore when the moles of acid or base present in the buffer solution is high enough the buffer solution will have a high buffer capacity. from the mistake of the student the number of moles present is lesser which means that the buffer solution will have a lower capacity
Hence the buffer will have a lower capacity because of the smaller number of moles of HF and F⁻ available to react is an acid or base is added.
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What is the maximum number of electrons that can be identified with each of following sets of quantum numbers? If there are none, enter 0.
Answer:
So, only one electron is there with n = 0, l = 0 and its quantum set is n = 0, l = 0, ml = 0, ms = -1/2. Hope, this is helping. The maximum number of electrons that can fit inside a 'n' shell is 2n^2. So it would be 1.
Explanation:
Quantum numbers are defined as the set of four numbers with the help of which we can get complete information about the electrons in an atom. Here the term 'n' represents the principal quantum number.
What is principal quantum number?The quantum number which represents the main energy level or shell in which electrons are present. It also determines the average distance of orbital or electron from the nucleus. It can have the whole number values like 1,2,3,4, ....
1. When n = 2, the maximum number of electrons present is 8. That is one 's' sub level and three 'p' sub levels. The spin of four electrons will be +1/2 and other four will be -1/2.
2. When l = 3, the possible orientations = 2l + 1 = 2(3) + 1 = 7. So the maximum number of electrons is 14.
3. The value of ml = -1 indicates only one orbital. So the maximum electrons is 2.
4. Here ml = -1, 0, 1 which shows three orbitals. So in ml = -1, there are only two electrons.
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One gallon of gasoline (C8H18) weights about 6.3 pounds. Burning gasoline with excess of oxygen forms water and carbon dioxide. When 3.1 gallons of gasoline burn, how many pounds of CO2 emit into the air?
FW: C = 12; H = 1; O = 16.
Answer:
60 pounds of CO₂ are emited into the air
Explanation:
The combustion of gasoline occurs as follows:
C₈H₁₈(l) + 25/2O₂(g) ⇄ 8CO₂(g) + 9H₂O
Where 1 mole of gasoline produce 8 moles of CO₂
To solve this question we must find the moles of gasoline in 3.1 gallons. 8 times these moles are the moles of CO₂ produced. With the moles of CO₂ we can find its pounds as follows:
Pounds gasoline:
3.1 gallons * (6.3 pounds / gallon) = 19.53 pounds
Grams gasoline:
19.53 pounds * (453.592g / pound) = 8859g
Moles gasoline -Molar mass C8H18: 114.23g/mol-
8859g * (1mol / 114.23g) = 77.55 moles gasoline
Moles CO₂:
77.55 moles gasoline * (8 mol CO₂ / mol Gasoline) = 620.4 moles CO₂
Mass CO₂ - Molar mass: 44.01g/mol-
620.4 moles CO₂ * (44.01g / mol) = 27304g CO₂
Pounds CO₂:
27304g CO₂ * (1lb / 453.592g) =
60 pounds of CO₂ are emited into the airHow many protons, neutrons, and electrons does potassium-38 have?
Answer:
19 protons, 20 neutrons and 18 electrons.
Explanation:
See if you can complete the following table using only what is on this page. Hint: Two of the entries are for the same element.
Element
Symbol
Nuclear
Symbol
Atomic Mass
Protons Neutrons Electrons
Number Number
83 Cu
29
Ga
67
31
29
36
Answer:
See attached picture.
Explanation:
Hello there!
In this case, according to the given information, it is possible to complete the table by knowing that the atomic number is the same to the number of protons equals those of electrons and that the neutrons are calculated by subtracting the atomic mass and the protons; thus, we are able to obtain the result as shown on the attached picture.
Best regards!
Determine the molar mass of a compound that has a density of 1.25 g/L at
STP. *
*
Answer:
So, weight per litre (1.25g/l) times 22.4 l/mole equals the mole weight (28 g/mole).
Please could you help me with this question
(No links or spam)
Will give brainliest if correct
Answer:
first one pure
second one mixture..
Explain the difference between wavelength and frequency
Answer:
Wavelength (typically measured in nanometers) is the distance between two points in a wave.Frequency (typically measured in Hertz) is the number of waves in a specific time . Frequency and wavelength have both direct and inverse relationships. The crucial difference between frequency and wavelength is that frequency shows the total number of wave oscillations in a given time. As against wavelength specifies the distance between two specific points of a wave.
Explanation:
Frequency is how often something changes per second be it amplitude of a voltage on a wire or be it the bobbing back and forth of a bobblehead. Frequency is how often something moves up and down in a second. If a bobble head moves forward and backward in one second then it has a bobbling frequency of 1 Hertz (Hz). The unit of frequency is Hertz (Hz) or # of cycles or oscillations per second. A wavelength is measured in distance like meters (m). For photons or light or radiowaves the equation is wavelength=speed of light/frequency.
Answer:
Wavelength (typically measured in nanometers) is the distance between two points in a wave, while frequency is how often something changes per second be it amplitude of a voltage on a wire or be it the bobbing back and forth of a bobblehead.
explain what is ment by solvent front
Answer:
In paper chromatography, the wet moving edge of the solvent that progresses along the surface where the separation of the mixture is occurring.
Explanation:
I hope this helps and pls mark me brainliest :)
What is the molarity (molar concentration, unit = M) of K+ found in 200 mL 0.2 M K2HPO4 solution?
Answer:
0.4 M
Explanation:
The process that takes place in an aqueous K₂HPO₄ solution is:
K₂HPO₄ → 2K⁺ + HPO₄⁻²First we calculate how many K₂HPO₄ moles are there in 200 mL of a 0.2 M solution:
200 mL * 0.2 M = 40 mmol K₂HPO₄Then we convert K₂HPO₄ moles into K⁺ moles, using the stoichiometric coefficients of the reaction above:
40 mmol K₂HPO₄ * [tex]\frac{2mmolK^+}{1mmolK_2HPO_4}[/tex] = 80 mmol K⁺Finally we divide the number of K⁺ moles by the volume, to calculate the molarity:
80 mmol K⁺ / 200 mL = 0.4 MIf aqueous solutions of Ba(OH)2 and HNO3 are mixed, what products are formed? Select one: a. BaN2(s) + H2O(l) b. Ba(NO3)2(aq) + H2O(l) c. Ba(s) + H2(g) + NO2(g) d. Ba2O(s) + NO2(g) + H2O(l) e. Ba3N2(s) + H2O(l)
Answer: Ba(NO3)2(aq) + H2O(l)
Explanation:
how many atoms is in 1 molacule of uranium?
Answer:
One mole of U238 ( 6.022 X 10^23 atoms) is 238 grams; one mole of U235 is 235 grams. The difference in molecular weight between a mole of U235 and U238 is 3 grams, the secret to enriching uranium.
Explanation:
Another name for a single-celled organism is
A. uni-cellular
B. one cellular
C. multi-cellular
D. eukaryotic
Answer:
A. Uni-cellular
Which of the following descriptions is correct?
А. a mixture consists of two or more pure substances which can only be separated by chemical methods
B. a colloid is a 'cloudy' mixture containing particles which will not easily settle out when the colloid is left standing
C. a solution consists of a solvent dissolved in a solute
D. a suspension contains particles which will not settle out if the suspension is left standing
Why do you think it would be important for scientists to test local water?
Answer:
It would be important because they will know if the water is infected by some type of disease or harmful bacteria
Explanation:
A ball of ice, rock, dust, and gas that orbits the Sun is called a(n) comet. asteroid. meteor. meteorite.
Answer: comet
Explanation: :)
What is the cation in KF?
Answer:
K, or Potassium
Explanation:
5. The following are energy releasing phase changes EXCEPT
A. Condensation B. Freezing C. Deposition D. Sublimation
Answer: All are energy releasing phase changes EXCEPT sublimation.
Explanation:
When molecules with high energy start to lose their energy and begin to settle down then heat energy is released in this process. Hence, this change is exothermic in nature.
When molecules with low energy absorb heat and start moving randomly from one place to another then molecules move to high energy level. Hence, this change is endothermic in nature.
Condensation - The conversion of gas phase into liquid phase is called condensation. Energy is released in this process.
Freezing - The conversion of liquid phase into solid phase is called freezing. Energy is released in this process.
Deposition - The conversion of gas phase into solid phase is called deposition. Energy is released in this process.
Sublimation - The conversion of a solid phase into gas phase without undergoing liquid phase is called sublimation. Energy is absorbed in this process.
Thus, we can conclude that out of the given options all are energy releasing phase changes EXCEPT sublimation.
The aforementioned options are energy releasing phase changes except: D. Sublimation.
What is a phase change?A phase change can be defined as the change in the state (phase) of matter of a given chemical compound or substance such as:
Gas to solidSolid to liquidLiquid to gasLiquid to solidIn Science, a change in the state (phase) of matter that results in the release of energy is known as an exothermic reaction such as:
CondensationFreezingDepositionIn conclusion, sublimation is not an energy releasing phase change because it is an endothermic reaction.
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why can't we humans live without oxygen? Can't we rely on something else? Why? Why oxygen out of all?
Answer:
because we need it to breathe
Explanation:
we breathe in oxygen and release carbon dioxide
Answer:
Ok i have a really weird theory.
Oxygen actually kills us we just don't know it yet. We need it too live but something in it also poisons us and causes us to die in around 100 years from birth. that's why we all die
real answer
we need it to breathe, when we breath we inhale in oxygen and release carbon dioxide which allows trees to grow and they produce more oxygen. We cant rely on anything else because oxygen is important and without it we die. Oxygen is one of the purist airs.
What kind of intermolecular forces act between a nitrogen trichloride molecule and a hydrogen sulfide molecule
Answer:
Dipole induced dipole force of attraction.
Explanation:
This is because dipole induced dipole attraction is a weak force of attraction or london force that occur when a polar molecule causes a form induction in a dipole in an atom or in a nonpolar molecule by altering the arrangement non polar electrons.
A 5.0L balloon in a freezer is at a temperature of - 50 degrees * C has a pressure of 800 mm Hg. What will be the new pressure if the balloon is taken out and placed in a warm room (Temperature 37°C) and the volume expands to 7.0 L?
Answer:
794 mmHg
Explanation:
We are going to be using the Combined Gas Law for this problem as well. Just to refresh out memory - the Combined Gas Law expresses the relationship between pressure, volume, and temperature (in KELVIN) of a fixed amount of gas. The equation itself? Right here: [tex]\frac{P_{1}V_{1}}{T_{1}} = \frac{P_{2}V_{2}}{T_{2}}[/tex]
Now, looking at the problem, let's assign the values to its corresponding variable:
P1 = 800mmHg; V1 = 5.0L; T1 = -50°C + 273 = 223K
V2 = 7.0L; T2 = 37°C + 273 = 310K; P2 = ?
We are looking to find the new pressure, a.k.a. P2. So, let's plug and chug the values into the equation.
Set up: [tex]\frac{(800 mmHg)(5.0L)}{223K} = \frac{(7.0L)(P_{2})}{310K}[/tex]
==> [tex]\frac{(800 mmHg)(5.0L)}{223K} * 310K = (7.0L)(P_{2})}[/tex]
==> [tex]P_{2} = \frac{(800 mmHg)(5.0L)}{223K} * \frac{310K}{7.0} }[/tex]
==> [tex]P_{2} =[/tex] 794.36 = 794 mmHg
Phosphorus reacts with oxygen to produce different kinds
of oxides. One of these oxides is formed when 1.347 g of
phosphorus reacts with 1.744 g of oxygen. What is the
simplest formula of this oxide?
Answer:
check below
Explanation:
You can find the empirical formula of phosphorus oxide
P O
____ ____
1.347g 1.744
1.347/ 31 1.744/ 16
0.043 0.109
0.043/ 0.043 0.109/ 0.043
1 : 2.5
2 : 5
P2O5
3) During the day at 27°C a cylinder with a sliding top contains 20.0 liters
of air. At night it only holds 19 liters. What is the temperature at night?
Answer:
[tex]T_2=12\°C[/tex]
Explanation:
Hello there!
In this case, according to the Charles' law equation which help us to understand the directly proportional relationship between volume and temperature:
[tex]\frac{T_2}{V_2}=\frac{T_1}{V_1}[/tex]
Thus, by solving for the final temperature, T2, and making sure we use the temperatures in Kelvin, we can calculate the final temperature as shown below:
[tex]T_2=\frac{T_1V_2}{V_1} \\\\T_2=\frac{(27+273)K*19L}{20.0L}\\\\T_2=285-273\\\\T_2=12\°C[/tex]
Best regards!
Best regards!
During the day at 27°C a cylinder with a sliding top contains 20.0 liters
of air. At night it only holds 19 liters and at that time temperature will be 12 °C.
What is Charles' law?Charles's law, a statement that the volume occupied by a fixed amount of gas is directly proportional to its absolute temperature, if the pressure remains constant.
According to Charles's law:
[tex]\frac{T_2}{V_2} = \frac{T_1}{V_1}[/tex]
Thus, by solving for the final temperature, [tex]T_2[/tex], and making sure we use the temperatures in Kelvin, we can calculate the final temperature as shown below:
[tex]T_2}= \frac{T_1 X\;V_2}{V_1}[/tex]
[tex]T_2}= \frac{(27 + 273)\; X\;19 liters}{20.0 liters}[/tex]
[tex]T_2= 12[/tex] °C
12 °C is the temperature at night.
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S- 2500m
112
VODO
4. Two waves are traveling in the same medium with a speed of 340 m/s. What is the difference in
frequency of the waves if the one has a wavelength of 5.0 m and the other has a wavelength of
0.2 m?
Answer:
1632 Hz
Explanation:
We'll begin by calculating the frequency of each wave. This can be obtained as follow:
1st wave:
Velocity (v) = 340 m/s.
Wavelength 1 (λ₁) = 5 m
Frequency 1 (f₁) =?
v = λ₁f₁
340 = 5 × f₁
Divide both side by 5
f₁ = 340 / 5
f₁ = 68 Hz
2nd wave:
Velocity (v) = 340 m/s.
Wavelength 2 (λ₂) = 0.2 m
Frequency 2 (f₂) =?
v = λ₂f₂
340 = 0.2 × f₂
Divide both side by 0.2
f₂ = 340 / 0.2
f₂ = 1700 Hz
Finally, we shall determine the difference in the frequency of both waves.
This can be obtained as follow:
Frequency 1 (f₁) = 68 Hz
Frequency 2 (f₂) = 1700 Hz
Difference =?
Difference = f₂ – f₁
Difference = 1700 – 68
Difference = 1632 Hz
1.
Why are kilometers not a good unit of measurement in space?
T.
2.
What distance measurement unit is used for objects within our solar system?
astronomical
units
3.
How many kilometers are in one astronomical unit?
4.
What distance measurement unit is used for objects outside of our solar
system?
_light
year!
5.
How many kilometers are in one light-year? I
How far away is the nearest star to Earth other than our Sun?
6.
7.
How far away is the center of the Milky Way Galaxy from Earth?
8.
What is the diameter of the Milky Way Galaxy?