Answer:
C
Explanation:
What causes blood pressure?
C
To pump blood around the body, the heart contracts and then relaxes through the cardiac cycle. The cycle begins with the contraction of the two atria, which push blood into the ventricles. Then, the ventricles contract, which forces the blood out of the heart.
When the heart pushes blood around the body during systole, the pressure placed on the vessels increases. This is called systolic pressure.
When the heart relaxes between beats and refills with blood, the blood pressure drops. This is called diastolic pressure.
Balance the combustion reaction between propane and oxygen.
C ₃ H ₈+ O ₂→ CO ₂ + H ₂ O
Answer:
The answer is C3H8 + 5O2 → 3CO2 + 4H2O .
Answer:
[tex]\huge \boxed{\mathrm{C_3 H_8 +5O_2 \Rightarrow 3CO_2 +4 H_2 O}}[/tex]
[tex]\rule[225]{225}{2}[/tex]
Explanation:
[tex]\sf C_3 H_8 +O_2 \Rightarrow CO_2 + H_2 O[/tex]
Balancing Carbon atoms on the right side,
[tex]\sf C_3 H_8 +O_2 \Rightarrow 3CO_2 + H_2 O[/tex]
Balancing Hydrogen atoms on the right side,
[tex]\sf C_3 H_8 +O_2 \Rightarrow 3CO_2 +4 H_2 O[/tex]
Balancing Oxygen atoms on the left side,
[tex]\sf C_3 H_8 +5O_2 \Rightarrow 3CO_2 +4 H_2 O[/tex]
[tex]\rule[225]{225}{2}[/tex]
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].
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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:
Ava’s best friend has an indoor cat. Ava notices that she sneezes every time that she visits her friend. Ava suspects that she is allergic to cats but is unsure. What is the best thing for Ava to do next?
C) Test her suspicion by going to see an allergist to diagnose the allergy.
It's right
1. Identify whether each of the elements is a metal, non-metal, or metalloid:
Ruthenium: Neon:
Germanium: Neptunium:
Iodine: Strontium:
Cesium: Europium:
Answer:
neon - non metal
Explanation:
Answer:
Ruthenium → metalloidNeon → non-metalGermanium → metalloidNeptunium → metalIodine → non-metalStrontium → metalCaesium → metalEuropium → metal
Balance the combustion reaction between octane and oxygen.
2C ₈ H ₁₈ + O ₂ → CO ₂ + H ₂ O
Answer:
The answer is 2C8H18 + 25O2 → 16CO2 + 18H2O .
(Correct me if I am wrong)
10 Points
Why was Dalton's theory of the atom incorrect?
A. Dalton theorized that atoms were too small to see but they are not.
B. Dalton' theory was correct.
C. Dalton theorized that had negative charges spread throughout them but they are
actually in electron shells.
D. Dalton theorized that atoms were indivisible but they are actually made of smaller
parts.
Reset Selection
Answer:
D
Explanation:
The indivisibility of an atom was proved wrong an atom can be further subdivided into protons, neutrons and electrons. However an atom is the smallest particle that takes part in chemical reactions......
hope i helped
pls mark brainliest,,,,,thanks
John Dalton was the chemist that gave the theory of atoms. His atomic model was incorrect as he said that the atoms cannot be further divided, but they are made of smaller particles. Thus, option D is correct.
What is Dalton's atomic model?Dalton's atomic model stated that all matter is composed of atoms that are made of elements with identical properties and mass. He further stated the formation of the compounds from the molecules.
In the theory, he stated that atoms cannot be divided further and are indivisible. This was proven wrong as the atoms are composed of sub-atomic particles namely, electrons, neutrons, and protons.
Therefore, the statement that atoms are indivisible in Dalton's atomic theory is incorrect.
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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
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.
Calculate Rations. A transformer has ten turns of wire on the input side and 50 turns of wire on the output side. if the input voltage is 120 V, what will the output voltage be?
Answer:
Output voltage = 600 V
Explanation:
Using the transformer equation which simply states that the ratio of the secondary to primary voltages in a transformer equals the ratio of the number of loops in their coils.
Number of input turns/Number of output turns = Voltage of input/voltage of output
10/50 = 120V/voltage of output
Voltage of output = 120 V/0.2
Voltage of output = 600 V
How much less carbon does
natural gas release than
coal?
Answer:
natural gas releases 50 to 60 percent less carbon dioxide than coal
Explanation:
Natural gas is a fossil fuel, though the global warming emissions from its combustion are much lower than those from coal or oil. Natural gas emits 50 to 60 percent less carbon dioxide (CO2) when combusted in a new, efficient natural gas power plant compared with emissions from a typical new coal plant [1].
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.
How does a salt bridge improve a battery
The role of the salt bridge is to assure the neutrality of both compartments.
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:
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]
What is the energy of light with a wavelength of 652 nm? (The speed of light in a vacuum is 3.00 x 108 m/s, and Planck's constant is 6.626 x 10-34 J·s.)
O A 3.05 x 10-²⁸ j
O B. 3.28 x 10¹⁸ j
O C. 3.05 x 10-¹⁹ j
D. 3.28 x 10²⁷ j
A and C have negative exponents pleas help me
Answer:
C. 3.05 x 10⁻¹⁹ J
Explanation:
Given;
wavelength of the light, λ = 652 nm = 652 x 10⁻⁹ m
speed of light, c = 3.00 x 10⁸ m/s
Planck's constant, h = 6.626 x 10⁻³⁴J·s
Energy of electromagnetic wave is calculated as;
E = hf
where;
f is frequency of the light wave
f = c / λ
[tex]E = hf = h\frac{c}{\lambda} \\\\E = \frac{hc}{\lambda} \\\\E = \frac{6.626*10^{-34}*3*10^8}{652*10^{-9}} \\\\E = 3.05*10^{-19} \ J[/tex]
Therefore, the energy of the light is 3.05 x 10⁻¹⁹ J
The correct option is "C"
C. 3.05 x 10⁻¹⁹ J
Answer:
Option C. 3.05 x 10¯¹⁹ J
Explanation:
Step 1:
Data obtained from the question.
wavelength (λ) 652 nm = 652x10^–9m
Velocity of light (v) = 3.00x10^8 m/s
Planck's constant (h) = 6.626x10^-34J·s
Step 2:
Determination of the frequency of the light.
The frequency can be obtained as follow
v = λf
3x10^8 = 652x10^–9 x f
Divide both side by 652x10^–9
f = 3x10^8 / 652x10^–9
f = 4.6x10^14s¯¹
Step 3:
Determination of the energy of the light wave.
This can be obtained as follow:
Planck's constant (h) = 6.626x10^-34J·s
Frequency (f) = 4.6x10^14s¯¹
Energy (E) =..?
E = hf
E = 6.626x10^-34 x 4.6x10^14s¯¹
E = 3.05 x 10¯¹⁹ J
Explain how you could use Avogadro's Law given the grams of a known compound and volume.
According to Avogadro's law, volume is directly proportional to number of moles which is in relation with the grams of a compound.
What is Avogadro's law?
Avogadro's law is a gas law which states that the total number of atoms or molecules has a direct proportion to the volume occupied by a gas at a constant temperature and pressure.
It is closely related to ideal gas equation as it links temperature, pressure, volume and the amount of substance.It is given as, V∝n,
The straight line graph of volume versus moles is a straight line passing through the origin which implies that zero moles of gas occupy zero volume.The law was proposed by Amedeo Avogadro in year 1811.
The law can be derived from the assumption of kinetic theory of gases considering their ideal behaviour.
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The government described in the passage most reflects the features of which type of democracy? No
The correct answer is B. Direct democracy
Explanation:
In a direct democracy, the citizens have a direct influence on government including laws, this means political decisions are made based on the opinion of citizens. This form of government differs from indirect democracy because in indirect democracy citizens only vote to choose representatives but do not participate directly in each political decision. The example presented is an example of direct democracy because even if some are not considered citizens, those who have the quality of "citizens" directly participate in the political decisions.
1. What is the wavelength of a photon of light with a frequency of 6.10 x 10^15 Hz?
Answer:
0.000000000000005 mm
Explanation:
Calcium nitrate, Ca(NO3)2 , is a(n) ___________________.
element
compound
heterogeneous mixture
homogeneous mixture
What do we call each step that makes up a reaction mechanism?
A. reaction step
B. individual step
C. Elementary Step
D. reactant step
Answer:
c elementary
Explanation:
they are formed and then created later
What is the energy of an electromagnetic wave with a frequency of 8 x 10^12
Hz?
A. 4.2 x 10-22 J
B. 2.4 x 1021 J
C. 1.59 x 10-12
D. 5.3 x 10-21 J
Answer:
Energy, [tex]E=5.3\times 10^{-21}\ J[/tex]
Explanation:
It is required to find the energy of an electromagnetic wave with a frequency of [tex]8\times 10^{12}\ Hz[/tex]. The energy of a wave in terms of its frequency is given by :
[tex]E=h\nu[/tex]
[tex]\nu[/tex] = frequency of em wave
[tex]E=6.63\times 10^{-34}\times 8\times 10^{12}\\\\E=5.3\times 10^{-21}\ J[/tex]
So, the energy of an electromagnetic wave is [tex]5.3\times 10^{-21}\ J[/tex]
Answer:
D. [tex]5.3 * 10^-21 J[/tex]
What is it called when Earth’s magnetic poles change places?
a.
a strike-slip fault
c.
sea-floor spreading
b.
magnetic reversal
d.
continental drift
Answer:
Its b. Magnetic reversal
Explanation:
Answer:
B
Explanation:
i just did it
Why arent the jaguars and sloths growing and thriving?
Answer:
Need more details to answer correctly.
Do you mean in general why are populations decreasing?
Well for jaguars this is due to poaching and deforestation.
For Sloths this is due to deforestation.
In an ecosystem, the jaguars and sloths are not growing and thriving due to deforestation and poaching.
What is an ecosystem?
Ecosystem is defined as a system which consists of all living organisms and the physical components with which the living beings interact. The abiotic and biotic components are linked to each other through nutrient cycles and flow of energy.
Energy enters the system through the process of photosynthesis .Animals play an important role in transfer of energy as they feed on each other.As a result of this transfer of matter and energy takes place through the system .Living organisms also influence the quantity of biomass present.By decomposition of dead plants and animals by microbes nutrients are released back in to the soil.
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When potassium chromate (K2CrO4) is added to a solution containing 0.500 g silver nitrate (AgNO3), solid silver chromate (Ag2CrO4) is formed. a) Determine the theoretical yield.
Answer:
Theoretical Yield = 0.4882 grams
Explanation:
Potassium Chromate = K2CrO4 Molar mass: 194.1896 g/mol
Silver Nitrate = AgNO3 Molar mass: 169.87 g/mol
Silver(I) Chromate = Ag2CrO4 Molar mass: 331.73 g/mol
Potassium Nitrate = KNO3 Molar mass: 101.1032 g/mol
K2CrO4 + 2AgNO3 = Ag2CrO4 + 2KNO3
Potassium Chromate + Silver Nitrate = Silver(I) Chromate + Potassium Nitrate
Ratio 1:2 = 1:2
0.5g AgNO3
AgNO3 Molar mass: 169.87 g/mol
2AgNO3 = 339.74grams
0.5/339.74 = 0.0014717
Ag2CrO4 Molar mass: 331.73 g/mol
0.4882 grams
Theoretical Yield = 0.4882 grams
Match each situation below to a letter on the illustration.
Ball
starts
here
Letter
Situation
Potential energy is the highest
Losing kinetic energy, gaining potential energy
Kinetic energy is highest
Losing potential energy, gaining kinetic energy
Answer:a
Explanation:
In the position A, the potential energy is maximum and the kinetic energy is minimum. At the point B, kinetic energy is highest. At the point C, the losing kinetic energy, gaining potential energy and at D, losing potential energy, gaining kinetic energy.
What is kinetic energy ?Kinetic energy of moving body is the energy generated by virtue of its position. Potential energy is generated by virtue of its position at a height from the surface. When a body starts moving from rest, its potential energy starts convert to kinetic energy.
As the height increases, potential energy increases. When an object moves down, its acceleration due to gravity increases and more energy to fall down make its kinetic energy higher.
Thus, the situations can be matched as follows;
A, the potential energy is maximum and the kinetic energy is minimum. B, kinetic energy is highest.
C, the losing kinetic energy, gaining potential energy and
D, losing potential energy, gaining kinetic energy.
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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 .
what element must combine with the metal for oxidation to take place?
Name three group l bases and three group ll bases
Answer:
Group 1: LiOH, NaOH, KOH
Group 2: Ca(OH)2, Sr(OH)2, Ba(OH)2
Explanation:
what happens to the zebra molecules once they are eaten by the cheetah?
Answer:
All living organisms need food for their body metabolism. Food helps in the provision of basic nutrients for the body’s survival and growth.
When the Cheetah eats the Zebra, enzymes acts on the Zebra molecules and converts it into smaller molecules.
The smaller molecules broken down are then readily absorbed and used by the cells of the Cheetah.