Answer:
c
Explanation:
valence is the number of electrons in the outer most she'll.. therefore all elements in the same group have the same valences for example group one elements have a valence of one
I hope this helps
Use Le Châtelier’s principle to predict what will happen to the following equilibrium if the volume is decreased.
2NH3(g) ↔ N2(g) + 3H2(g)
Answer:
The reverse reaction is favoured
Explanation:
According to the principle; when a constraint such as a change in concentration, pressure, temperature etc is imposed on a reaction system in equilibrium, the equilibrium position will shift in such a direction as to annul the constraint.
In this case, the constraint is a change in volume. If the volume is decreased, the reverse reaction (leading to less total volume) is favoured.
The forward reaction leads to four volumes while the reverse reaction leads to only two volumes. Decrease in volume favours the direction in which the total volume is lower.
Why do the fourth and fifth periods contain 18 elements rather than 8 as observed in the second and third periods?
The fourth and fifth periods contain 18 elements rather than 8 as observed in the second and third period because of the accommodation of 10 additional electrons in the 3d orbital.
The number of orbitals that can be accommodated by s subshell is one, p subshell is three, d subshell is five and f subshell is seven.
In the second and the third period, the 2s subshell is filled with two electrons, 2p subshell with six electrons .So, the second period contains eight elements. The sequence in third period is similar to that of second period with additional filling of 3s and 3p subshell.
In the fourth period, electrons are first filled in the 4s subshell, only after that they can be filled in the 3d subshell. So, fourth period contains 18 elements , which is due to the additional 10 electrons in 3d subshell. This is similar in the case of fifth period also.
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Are group 1 or group 2 elements more reactive?
The elements belonging to group 1 are more reactive than elements belonging to group 2.
The elements that belongs to s block elements are hydrogen (H), lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), and francium (Fr). The nature of alkali metals is soft and shiny in appearance. They have low melting point and are highly reactive in nature and usually tarnish when exposed to air. Sodium (Na) is the most reactive element since it's valence electrons are not tightly held together in the atom. The three elements that are highly reactive are Lithium (Li), Sodium (Na), and potassium (K). The elements toward the bottom left corner of the periodic table are the metals that are the most active in the sense of being the most reactive.
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What type of elements for ionic bonds with one another ?
Answer:
metals and nonmetal ions
Explanation:
Ionic bonds form when a nonmetal and a metal exchange electrons, while covalent bonds form when electrons are shared between two nonmetals. An ionic bond is a type of chemical bond formed through an electrostatic attraction between two oppositely charged ions.
J.J Thomson's experiments provided what evidence about atoms?
a) atoms are the smallest particles of matter
b) atoms contain negatively charged particles
c) atoms have a negative charge
d) atoms have a positive charge
32P has a half life of 14 days calculate the time taken for a given amount of 32P to decay to one - eight of its original activity
The time taken for a given amount of 32P to decay to one-eight of its original activity is 42 days.
A substance's half-life is the amount of time it takes for half of it to decompose. Given that each half-life period diminishes the activity by a factor of 2, if a given amount of a material with a half-life of 14 days decays to one-eighth of its initial activity, it must have gone through three half-life periods. Therefore, it would take 14 x 3 = 42 days for a given amount of 32P to decay to one-eighth of its initial activity.
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is the specific heat capacity of gaseous ethanl greater than. less thean or equal to the speciifc heat captity of liquid ethanol
The specific heat capacity of the gaseous ethanol is less than the specific heat capacity liquid ethanol.
The specific heat capacity is given as :
Q = mc ΔT
where ,
Q = heat
m = mass
c = specific heat capacity
ΔT = temperature change
The heating curve represented the temperature , T in the y axis and the heat added at the x - axis. the slope is given as :
T / Q = 1 / C
T is the temperature and the c is the specific heat capacity.
Thus, the heat capacity of the gaseous ethanol is low as compared to the liquid ethanol.
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A compound with EF CH2 was found to have a Molar mass of 84g. What is the MF of the compound?
Answer:
C6H12
Explanation:
MM = 84g
CH2 = 12+2 =14g
Hence, 84/14 = 6g/mol
CH2 x 6 = C6H12
In a reaction between vinegar and antacid tablets, the antacid is the limiting reagent. At constant pressure and temperature, three tablets produce 600 cm³ of gas.
What volume will six tablets produce?
The volume of gas produced by six tablets would be twice the volume produced by three tablets, or 600 cm³ x 2 = 1200 cm³.
Definition of a gas's volumeUntil they are enclosed in a container, gases lack a definite shape or volume. Gases can expand and contract as they are forced into various container sizes and shapes because of the way their molecules spread out and move randomly.
The volume of the container in which a gas is contained can be used to define the volume of the gas itself.
The volume of a gas reduces as the molecules are crammed closer together when it is compressed. A gas's volume rises when it expands.
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Answer:
1200 cm³.
Explanation:
What are the types of chemical bonds? Describe each.
What are two physical properties of lead?
Answer:
low melting point, high density, and acid resistance
Explanation:
If a bond forms between calcium and chlorine, the bond is covalent.
True or False
Answer:
False
Explanation:
there should be sharing of electrons between two of the atoms to be a covalent bonding. but there is no linkage of electron between them
ill mark u brainlest if u answer me wit no links!
Which of these best describes the brainstorming stage of the engineering design process?
identifying a need to be addressed
gathering feedback about prototypes
collecting information from a variety of background sources
using group input to discuss and prepare preliminary designs
Answer: I believe it would be using group input to discuss and prepare preliminary designs
Explanation:
How do you calculate number of molecules?
Determine the substance's molecular weight in units of one mole, then divide the molar mass value by the molecular mass, and multiply the result by the Avogadro constant to get the required number of molecules.
It is possible to determine the number of molecules by using the relationship between the number of moles and Avogadro's number, which is provided by;
1 mole = Avogadro's constant (NA)
The number of molecules will equal the product of the number of moles and Avogadro's number, which is determined after the number of moles has been determined
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7. Explain the role of the digestive system in animals, as well as how the system works! PLEASE I WILL GIVE BRAINLIEST
How does burning forest impact the atmosphere
Answer: The smoke can deplete the ozone layer
like tobacco smoke, the aerosol given off by an e-cigarette can contain dangerous chemicals.
The title "e-cigarettes," sometimes known as "electronic nicotine delivery systems" (ENDS) and infrequently "electronic non-nicotine delivery systems," refers to a wide range of distinct products (ENNDS).
By heating the liquid, these systems can produce aerosols that the user inhales. These so-called e-liquids typically contain additives, flavours, and chemicals that can be harmful to people's health, alongside nicotine (but no tobacco), which could or may not been present.
The deadly mixture of 7,000 hazardous substances in cigarette smoke is generally lower prevalent in e-cigarette aerosol than it is. 3 Aerosol produced e-cigarettes is not risk-free, though.
It may include toxic or carcinogenic drugs include tobacco, contaminants like lead, volatile compounds, and melanoma agents.
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magine a population of rabbits in the woods.
What would happen if the rabbit population continued to decrease?
CHOOSE ALL THAT APPLY
Lesson 5.06
Question 17 options:
Animals that prey on rabbits would begin to prey on other organisms.
none of the choices
Animals that prey on rabbits would starve.
Animals that prey on rabbits would leave the area in search of more rabbits.
Answer:
A.) They would have to prey on other organisms
Explanation:
The answers are.....
Animals that prey on rabbits would begin to prey on other organisms.
And...
Animals that prey on rabbits would starve.
And...
Animals that prey on rabbits would leave the area in search of more rabbits.
My son attends K12 and had this question on his unit 5 test. These were his answer choices and they were correct.
helpp!!
1.) How many protons?
2.) How many neutrons?
3.) How many electrons?
Answer:
1) 33
2)47
3)33
Explanation:
The atomic number 33 is the same for both protrons and electrons.
In what part of this system are the two energy outputs found?
The part of the system that has two outputs of energy is the bulb.
What is the energy transformation?We would have to recall that on the basis of the first law of thermodynamics, it can be said that energy can not be created nor destroyed but that energy would have to be converted from one form to the other.
In this case, we can see that as the boy is cycling, there is the conversion of the mechanical energy of the boy to the heat and the light energy of the bulb as shown. These are the outputs referred to above.
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The rate of effusion of a particular gas was measured and found to be 21.0 mL/min. Under the same conditions, the rate of effusion of pure methane (CH4) gas is 47.0 mL/min. What is the molar mass of the unknown gas
the particular gas effusion was 21.0. and the methane effusion rate is 47.0 The molar mass of the unknown gas is approximately 28.6 g/mol
The process through which a gas manages to escape through with a small hole or highly permeable barrier is known as effusion. A gas's rate of effusion is inversely proportional to its molar mass squared. The following equation describes this relationship: rate1 / rate2 = (sqrt(molar mass2) / sqrt(molar mass1)). where rate1 and rate2 are the rates of effusion of the two gases and molar mass1 and molar mass2 are the molar masses of the two gases.Given the rate of effusion of the unknown gas is 21.0 mL/min, and the rate of effusion of pure methane (CH4) is 47.0 mL/min, we can use the above equation to find the molar mass of the unknown gas:
(21.0 mL/min) / (47.0 mL/min) = sqrt(molar mass unknown) / sqrt(16.04 g/mol)
Squaring both sides of the equation, we get:
(21.0 mL/min)^2 / (47.0 mL/min)^2 = (molar mass unknown) / (16.04 g/mol)
Solving for molar mass unknown we get:
molar mass unknown = (16.04 g/mol) * (21.0 mL/min)^2 / (47.0 mL/min)^2
The molar mass of the unknown gas is approximately 28.6 g/mol
Please note that the above calculation is based on the assumption that the temperature and pressure are the same for both gases and that the gases are ideal
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Isabella tiene una pileta que tiene una superficie de 678,32 dam2 mientras que Tadeo tiene una de 865,42 dm2. ¿Cuál pileta tiene mayor superficie?
Isabella has a pool that has an area of 678.32 dam² while Taddeo has one of 865.42 m². Which pool has the largest surface area?
Solution :
We know, 1 dam² = 100 m².
So, area of Isabella pool in m² is :
A = 678.32 × 100 m² = 67832 m² .
Therefore, area of Isabella is greater that volume of Taddeo .
Calculate the final pressure in the cylinder of a car engine if the original volume was 450
mL at a pressure of 0.80 aim, and the final volume is 120 mL. Assume no change in the
number of molecules or ternperature.
According to the Boyle's law, the final pressure of gas in cylinder is 3 atmospheres.
What is Boyle's law?Boyle's law is defined as an experimental gas law which describes how the pressure of the gas decreases as the volume increases. It's statement can be stated as, the absolute pressure which is exerted by a given mass of an ideal gas is inversely proportional to its volume provided temperature and amount of gas remains unchanged.
Mathematically, it can be stated as,
P∝1/V or PV=K. The equation states that the product of pressure and volume is constant for a given mass or amount of gas and the equation holds true as long as temperature is maintained constant or does not change.
According to the equation the unknown pressure and volume of any one gas can be determined if two gases are to taken in consideration.That is,
P₁V₁=P₂V₂
∴P₂=0.8×450/120=3 L.
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If an automobile air bag has a volume of 11.8 L, what mass of (in g) is required to fully inflate the air bag upon impact
22.3 g of NaN₃ are required to fully inflate an airbag of 11.5 L at STP.
What is decomposition reaction?Chemical decomposition, also known as chemical breakdown, is the process of breaking down a single chemical entity into two or more components. Chemical breakdown is commonly thought of and characterized as the inverse of chemical synthesis. When one reactant breaks down into two or more products, this is referred to as a decomposition reaction. This is expressed by the following generic equation: AB A + B. The breakdown of hydrogen peroxide to water and oxygen is an example of a decomposition process, as is the breakdown of water to hydrogen and oxygen.
Here,
In airbags, sodium azide decomposes to form sodium and nitrogen gas, which inflates the bag. The decomposition reaction is:
2 NaN₃ ⇒ 2 Na + 3 N₂
We can calculate the mass of NaN₃ needed to produce 11.5 L of N₂ at STP, using the following relations.
At STP, 1 mole of N₂ occupies 22.4 L.
The molar ratio of N₂ to NaN₃ is 3:2.
The molar mass of NaN₃ is 65.01 g/mol.
=11.8*1/22.4*2/3*65.01/1
=118/112*21.67
=22.82 g
22.3 g of NaN₃ are required to fully inflate an airbag of 11.5 L at STP.
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why was the bohr model replaced
Answer:
The Bohr model of the atom was replaced by the quantum mechanical model because it was unable to explain the behavior of electrons in atoms. The quantum mechanical model was able to explain the behavior of electrons in atoms more accurately.
Explanation:
Which isotope, when bombarded with nitrogen-15, yields the artificial isotope dubnium-260 plus 4 neutrons
The isotope that when bombarded with nitrogen-15 yields the artificial isotope dubnium-260 plus 4 neutrons is californium-249.
Californium-249 is a heavy element and when bombarded with nitrogen-15, which is a light element, undergoes a nuclear reaction known as a "cold" fusion reaction. This reaction results in the formation of the artificial isotope dubnium-260, which has a higher atomic number than the starting element and the release of 4 neutrons.This process is known as a Nuclear Transmutation, which is a process in which one element is converted into another element by bombarding it with a beam of particles such as protons, neutrons, or other ions.
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How many grams do 5.6 × 1026 atoms of helium weigh?
One mole of Helium contains 6.02 × 10²³ atoms. Mass of one mole is 4 g. Then, He containing 5.6 × 10²⁶ atoms weighs 3720.9 g.
What is Avogadro number?Any substance containing 6.02 × 10²³ atoms is called one mole of that substance. This number is called Avogadro number. Thus, one mole of every element contains Avogadro number of atoms.
Helium is second element in periodic table. Atomic mass of helium that is mass of one mole = 4 g
4 g contains 6.02 × 10²³ atoms. Then weight of He containing 5.6 × 10²⁶ atoms is calculated as follows:
no. of moles = 5.6 × 10²⁶/ 6.02 × 10²³ = 930.2
mass of 930.2 moles = 930.2 × 4 =3720.9 g
Therefore, the mass of He containing 5.6 × 10²⁶ atoms is 3720.9 g.
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consider three identical flasks with different gases. in which flask will the molecules have the greatest average velocity
The flask A, flask B, flask C, all have equal average kinetic energy at 0°C.
What is the average kinetic energy?The average kinetic energy of the particles in a gas is inversely related to its temperature. These particles must move more quickly as the gas warms because their mass is constant.
KE avg = 3/2RT
As a result, it is possible to state that average kinetic energy depends on temperature. As a result, as the temperature rises, the gas molecules become more energetic and move at a faster rate.
The average kinetic energy also stays the same because, in accordance with the question, the temperature is constant across all flasks.
Therefore, the average kinetic energy of flasks A, B, and C at 0°C is the same.
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Complete question is " Consider three identical flasks with different gases:
Flask A: CO at 760 torr and 273 K
Flask B: N₂ at 250 torr and 273 K
Flask C: H₂ at 100 torr and 273 K
In which flask will the molecules have the greatest average kinetic energy per mole?
What is the molarity of a solution in which 0.23 moles of NaCl are dissolved in enough water to make 395.6 mL of solution
The molarity of NaCl in enough water is 0.582[tex]\frac{mol}{mL}[/tex]
The moles of NaCl is given which is 0.23 and NaCl is dissolved in enough water which makes the solution of 395.6 mL.
The total number of moles of solute present in a given solution per litre is known as its molarity. In contrast to mass, which varies as the system's physical circumstances vary, the volume of a solution changes as a function of changes in the system's physical qualities, such as pressure and temperature. This has an impact on the molality of the solution. The symbol M, sometimes known as a molar, denotes molarity. A solution is considered to be one molar when one gram of the solute dissolves in one litre of the solution.
So, the molarity= [tex]\frac{totalnumber of moles}{total volume }[/tex]
molarity=[tex]\frac{0.23}{0.395}[/tex]
molarity=0.582[tex]\frac{mol}{mL}[/tex]
Hence, the molarity is 0.582.
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A man-made device that is used to replace or enhance a body part is called
what?
A. A nanotube
B. A scaffold
C. A prosthesis
D. A pacemaker
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A man-made device that is used to replace or enhance a body part is called :
A. A nanotube
B. A scaffold
C. A prosthesis
D. A pacemaker
➜Option C. A prothesis is correct!
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