b) The size of a star is a balance between
2 things. Explain this statement.

Answers

Answer 1

Answer:

Luminosity is the amount of light that a star radiates. The size of the star and its surface temperature determine its luminosity. Apparent magnitude of a star is its perceived brightness, factoring in size and distance, while absolute magnitude is its true brightness irrespective of its distance from earth

Explanation:


Related Questions

A reaction happens quickest during:
A. The beginning of the reaction
B. It is constant throughout the reaction
C. The end of the reaction
D. The middle of the reaction

Answers

The answer is A
Explanation;
At the start of the reaction, when we first put magnesium in the hydrochloric acid, there is 100% of the magnesium to react with. As a result there will be more successful collisions between the reactant particles. The more successful collisions, the faster the reaction will be.

The reaction is the formation of the product from the reactants. A reaction happens quickest during the beginning of the reaction. Thus, option A is correct.

What are the factors affecting the reaction rate?

The reaction rate is the pace at which the reaction takes place and the breakdown or the combination of the reactants to produce the products. The rate of reaction depends on the concentration of the reactants.

The concentration of the reactants is in direct proportion with the rate as at the beginning of a reaction there is a higher amount of substance present than at the end.

As the reaction proceeds, the reactants get consumed and their concentration decreases. As there is a decrease in concentration the rate of the reaction converting and producing the products also decreases.

Therefore, option. the rate of reaction is fast at the beginning.

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Energy in the amount of 420 J is added to a 35 g sample of water at a temperature of 10°C. What is the final temperature of the water?

Answers

The final temperature of the water, T2 = 38.57°C

Temperature can be defined as a measure of the degree of hotness or coldness of a physical object (body). Thus, it is measured with a thermometer and its units are degree Celsius (°C), Fahrenheit (°F) and Kelvin (°K).

A calorie refers to the amount of heat required to raise the temperature of a gram of water by one (1) degree Celsius (1°C).

Given the following data:

Quantity of energy = 420JMass = 35 gramsInitial temperature, T1 = 10°C

The specific heat capacity of water is 4.2 J/g°C.

To find the final temperature of the water (T2):

Mathematically, the quantity of energy (heat capacity) is given by the formula;

[tex]Q = mcdt[/tex]

Where;

Q represents the heat capacity or quantity of heat.M represents the mass of an object.C represents the specific heat capacity of water.dt represents the change in temperature.

Substituting the values into the formula, we have;

[tex]420 = 3.5 \; * \; 4.2 \; * \; dt[/tex]

[tex]420 = 14.7 \; * \; dt\\\\dt = \frac{420}{14.7}[/tex]

Change in temperature, dt = 28.57°C

Next, we would solve for the final temperature by using this formula;

[tex]dt = T2 - T1[/tex]

[tex]28.57 = T_{2} - 10\\\\T_{2} = 28.57 \; + \; 10\\\\T_{2} = 38.57[/tex]

Final temperature, T2 = 38.57°C

Therefore, the final temperature of the water, T2 is equal to 38.57°C

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how is electrovalent bond formed ? Describe with an example .​

Answers

Answer:

For example, the bond between the sodium and chlorine atoms in sodium chloride (NaCl) is formed by the transfer of an electron from sodium to chlorine, creating Na + and Cl – ions. ... The electrostatic attraction between these ions provides the bonding in NaCl.

precautive measures taken when using pooter​

Answers

I guess ensuring that you don't suck the insects or specimen collected by ensuring there is a net in the pooter

which best describes nuclear energy?
A the energy that matter has due to the vibrations of its particles
B the energy an object has due to its chemical bonds
C the energy generated by a flow of electrons
D the energy stored inside the center of an atom

Answers

Answer:

The correct answer is - D.  the energy stored inside the center of an atom.

Explanation:

Each atom has a small center in it called the nucleus and the energy that holds the nucleus or center of the atom together in the atom is known as nuclear energy.

It is the energy that is stored in the center of the atom and normally does not come out, however, in some radioactive atoms the sends some part of the energy as radiation.

Thus, the correct answer is - D.  the energy stored inside the center of an atom.

The atomic number of silicon (Si) is 14. What's the electron configuration for silicon? Question 1 options:
A) [Ar] 3p5
B) [He] 1s2 2p6
C) [Ne] 3s2 3p2
D) [He] 2s2 3p2

Answers

Answer:

D.[Ne] 3S2 3P2

Explanation:

The electron configuration for silicon is  [Ne] 3s² 3p². Hence Option (C) is correct.

What is elctronic configuration ?

Electronic configuration, also called electronic structure or electron configuration, the arrangement of electrons in orbitals around an atomic nucleus.

The electron configuration of an element describes how electrons are distributed in its atomic orbitals.

Electron configurations of atoms follow a standard notation in which all electron-containing atomic subshells (with the number of electrons they hold written in superscript) are placed in a sequence.

Silicon belongs to group 14th and 3rd period.Therefore, The electron configuration for silicon is  [Ne] 3s² 3p². Hence Option (C) is correct.

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Pesticides and fertilizers are a major cause of
O air pollution
O acid rain
o the greenhouse effect
O groundwater pollution


Answers

Answer:

it means air pollution Environment. The chemicals and nutrients found in fertilizers, while beneficial for agricultural crops, can be lethal in high doses for fish, birds and other wildlife. Pesticides, designed to kill pests chemically, are also dangerous when leached into soil or groundwater supplies.

What type of Nuclear decay is shown by the reaction below

Answers

Answer:

bete is your answer.

have a great day.

I think c ....is write answers

what is the requirements to obtain citizenship?

please answer it correctly​

Answers

Answer:

Age. ...

Residency. ...

Residence and Physical Presence.

Good Moral Character.

Attachment to the Constitution.

Language.

U.S. Government and History Knowledge.

Oath of Allegiance.

These are some requirements for obtaining citizenship .

Age
Culture
Race
Background

Arrange the steps in order to describe how photons and carbon dioxide (CO2) contribute to the warming of Earth.

CO2 in the atmosphere absorbs infrared
photons.

CO2 in the atmosphere emits infrared photons back toward Earth.

Photons from the Sun strike Earth and become infrared photons.

Earth radiates infrared photons into the atmosphere

The Sun radiates sunlight (visible)
photons

Answers

The Sun radiates sunlight (visible)  photons

Photons from the Sun strike Earth and become infrared photons.

Earth radiates infrared photons into the atmosphere

CO2 in the atmosphere absorbs infrared  photons.

CO2 in the atmosphere emits infrared photons back toward Earth.

Certain gases are known to contribute towards global warming. Such gases are called greenhouse gases. The infrared rays from the sun are absorbed by these gases as they are re-emitted from the earth and re-emitted.

The sun radiates photons to the earth which is re-radiated into outerspace from the earth's surface. CO2 and other greenhouse gases absorbs these gases and re-emit them to the earth thereby causing a gradually rise in the temperature of the earth called global warming.

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H3C6H507 + H2O + H3O+ + H2C6H507
acid
base

Answers

Explanation:

an acid will give away a proton and become a conjugate base.

A base will accept a proton and become a conjugate acid.

What is known about a reaction with a negative enthalpy?
A. The reaction is endothermic,
B. The reaction is spontaneous,
C. The reaction is exothermic,
D. The reverse reaction is favored,

Answers

Considering the definition of enthalpy of reaction, the correct answer is option C. a reaction with a negative enthalpy indicates that the reaction is exothermic.

Definition of enthalpy of reaction

The enthalpy of a chemical reaction as the heat absorbed or released when chemicals are transformed into a chemical reaction and it occurs at constant pressure.

The enthalpy is an extensive property, that is, it depends on the amount of matter present.

Finally, it must be taken into account that:

A reaction is called exothermic if its enthalpy of reaction is negative (that is, if the system gives up heat).A reaction is called endothermic if its enthalpy of reaction is positive (that is, if the system absorbs heat).

Summary

In summary, a reaction with a negative enthalpy indicates that the reaction is exothermic.

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What is the chemical formula for carbon tetrafluoride?
The Periodic Table
1
mono-
2
di-
3
4
tetra-
5
penta-
hexa-
6
7
hepta-
8
Oct-
9
nano-
10
deca-

Answers

the chemical formula for carbon tetrafluoride is CF4 because carbon has a charge of -4 and fluorine has a charge of -1 so to balance the ions, you must balance the charges.

what are the defects of mendeleev's periodic table​

Answers

Answer:

1 Anomalous Pairs. The rest of the  pairs of elements don't follow the follow Mendeleev's Principles . they are :

2Grouping of chemically dissimilar elements.  

3Position of Isotopes.  

4Electronic arrangement.  

5Separation of chemically similar elements.  

6The position of hydrogen.

Assertion (A): An orbital cannot have more than two electrons, moreover, if an orbital has two electrons they must have opposite spins.
Reason (R): No two electrons in an atom can have the same set of all the four quantum
numbers.
a) Both A and R are true and R is the correct explanation of A.
b) Both A and R are true but R is not the correct explanation of A.
c) A is true but R is false.
d) Both A and R are false.
pls answer

Answers

Answer:

the correct answer is option ( A )

Both A and R are true and R is the correct explanation of A.

Explanation:

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PLS GUYS ITS FOR 10TH GRADE CHEM

Answers

Answer:

1. 2.63x10^6

2. 39.2

Both answers have been rounded

If an atom has three shell and number of valence electrons are two. Is this element metal
or non-metal and why? Name the element and it’s valency.

Answers

Answer:

Metal

Element: Calcium

Valency: 2

Explanation:

To find the element, let's use the periodic table. (Look below)

We already went past 3 shells, just need the 2 electrons after it.

Just skip to the 4th row and count 2 to the right

We end up at Calcium.

Calcium is a metal and we're also on the alkaline earth metals column.

Calcium will need to lose 2 electrons to reach stability, so the valency is 2.

what is plasma in chemistry​

Answers

Explanation:

Plasma is an ionized gas, a distinct fourth state of matter. “Ionized” means that at least one electron is not bound to an atom or molecule, converting the atoms or molecules into positively charged ions.but plasma is present in human body too in a liquid form.

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have a nice day

What is the order, plz answer

Answers

Answer:

C A B

Explanation:

come on, you also know this from normal water waves.

which ones are stronger (= have more energy) ? the small ones or the big ones ?

and the same applies to all waves. the bigger the waves (higher amplitude), the more energy.

define SI unit system​

Answers

Answer:

The SI base units are the standard units of measurement defined by the International System of Units (SI) for the seven base quantities of what is now known as the International System of Quantities: they are notably a basic set from which all other SI units can be derived.

WHICH STATEMENT BEST REPRESENTS A HYPOTHESIS

Answers

Answer:

D

Explanation:

Hypotheses are educated guesses, and the best answer is the one with an if, as it indicates that it's a guess.

Answer:

letter b should be the answer

En una carrera de atletismo un deportista se muestra agotado sin fuerzas para continuar y decide abandonar la carrera ¿Que alimentos tomo antes de la carrera ?

Answers

Answer:

Los alimentos para evitar la fatiga durante una carrera son alimentos bajos en grasas y altos en carbohidratos, así como alimentos bajos en fibra como pan, mantequilla de maní, plátano, jugo de frutas sin pulpa, y beber hasta aproximadamente 600 ml de líquido aproximadamente 3 horas. antes de la carrera

La comida para comer unos días antes de la carrera incluye carnes magras, arroz, pasta y verduras con contenido de almidón.

Los alimentos que se deben evitar incluyen carne roja, alimentos con alto contenido de grasas saturadas, alimentos fritos, pasteles y salchichas.

Explanation:

A pupil has drawn the electronic structure of fluorine and the diagram is shown below. However,
mistakes have been made. State three mistakes that have been made.

Answers

The first shell can only hold 2 electrons, but the pupil placed in 8 electrons.

The second shell can hold up to 8 electrons, but the pupil only placed in 2 electrons.

Flourine only has 9 total electrons, yet there are 10 electrons in the diagram.

Answer:

Explanation:

In the Fluorine atom there are 2 electrons in the innermost shell and 7 i the outer shell.

Did you know that before pencil erasers were added on in 1858. people got rid of pencil markings
with white breadcrumbs? Which would erase pencil markings better, an eraser or white bread
crumbs?

Make a hyphotesis plz

Answers

Answer:

I guess eraser is better than bread crumbs

Erasers would be better than white bread or crumbs to erase the pencil marks because they would not leave any food marks on the paper and using bread crumbs.

What is an eraser?

An eraser is an object of stationary which is used to remove pencil marks from the paper. It is used during writing, when we write something wrong, we could erase or remove the writing from the paper. It is very useful for small children because they usually make mistakes while studying.

Erasers are made from the milk of rubber plants. The milk is collected from the plants, and then it is mixed with chemicals and set down, and then cut into pieces.

Thus, Erasers would be preferable to utilizing bread crumbs or white bread because they would not leave any food stains on the paper after erasing the pencil markings.

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The process of diffusion can be described as: Movement of water from the area of high concentration of solute to the area of low concentration of solute. Movement of solute from the area of low concentration of solute to the area of high concentration of solute. Movement of water from the area of low concentration of solute to the area of high concentration of solute. Movement of solute from the area of high concentration of solute to the area of low concentration of solute.

Answers

Answer:

Movement of water from the area of high concentration of solute to the area of low concentration of solute.

Explanation:

Diffusion can be defined as the movement of gas molecules from a region of high concentration to a region of lower concentration until an equilibrium is attained or reached. This mixing of gas molecules in the liquid or gaseous state is due to their kinetic energy of random motion i.e without requiring bulk motion.

This ultimately implies that, diffusion is a phenomenon through which gas molecules in either a gaseous or liquid state spread out in response to a concentration gradient, which is simply the difference in concentration of the gases across a space.

During diffusion, molecules move from areas of high concentration to areas of low concentration. Also, diffusion does not require energy to move molecules.

Hence, the process of diffusion can be described as movement of water from the area of high concentration of solute to the area of low concentration of solute.

A solute can be defined as a substance that is typically dissolved in a liquid solvent such as water, coffee, tea, etc., to produce a solution.

Câu 6: Cho 4,2 gam este đơn chức no E tác dụng hết với dung dịch KOH ta thu được 4,76

gam muối natri. Vậy công thức cấu tạo của E có thể là:

Answers

Please translate this in English or Korean and I’ll be happily help :)

Sorry I just don’t understand this language nor know It or I would translate myself

What's a third reaction? (Chemistry)

Answers

Explanation:

a chemical reaction in which the rate of reaction is proportional to the concentration of each of three reacting molecules

Matty told Harriet that, later that same day, he was going to try to convince her to change her attitude toward the nutritional merits of doughnuts. Based on research findings regarding persuasion, how effective is Matty's strategy?

Answers

Answer:

The correct answer is - not very effective; forewarning tends to reduce the effectiveness of an attitude change

Explanation:

The strategy of forewarning or warning before attempting any change in the psychology of an individual is found to be less effective. The subject sees a  forewarning seen as a warning that a person is going to attempt to make changes in the attitude of a person about a particular thing or situation.

As a result, the person is ready to defenses up with regard to that idea of persuasion which Builds up defenses for the situation. Therefore, the effect of persuasion is reduced on the person.

Thus, Matty's strategy is not very effective; forewarning tends to reduce the effectiveness of an attitude change

A student wants to separate a mixture of salt and water in a laboratory (a) Describe how the student can obtain both salt and water from the salt solution​

Answers

Answer:

okay so basically what you are being tested is if you know the difference between simple and fractional distillation and okay you can evaporate the mixture but you won't obtain water so you will use simple distillation to obtain both salt and water

One the first chemistry test. 12 students got As, 18 students got Bs, and 20 students got Cs.

a. What is the percentage of students received Bs.

b. What is the percentage of students who received Cs?
Express your answer to the ones place.

Answers

Answer:

A. 36 percent recieved Bs

B. 40 percent of students received Cs

Explanation:

Amount of students: 12+18+20=50

Students with Bs: (18÷50) x 100 = 36%

Students with C's: (20÷50) x100 = 40%

On the first chemistry test 12 students got A, 18 students got B, and 20 student got C. Thus the percentage of students received B is 0.36 and percentage of students received c is 0.40

What is the percentage of students received B and C?

In mathematics, a number or ratio expressed as a fraction of 100. It is often denoted using the percent sign %. A percentage is a dimension less unit and it has no unit.

In above question 12 student got A, 18 student got B, and 20 student got C.

So total number of student = 12 + 18 + 20 = 50.

Then the percentage of students received B is as follows:-

Percentage of students who got B = (student who got B/Total number of student) X 100.

=(18/50) X 100

= 36%

Now percentage of students who got C = (No of students who got C/Total students)X100

=(20/50) X 100

=40%.

Therefore,On the first chemistry test 12 students got A, 18 students got B, and 20 student got C. Thus the percentage of students received B is 0.36 and percentage of students received c is 0.40 percentage of students who got B is 36% and percentage of students who got C is 40%

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cho 11,2 lit hn hp gm metan v etilen tc dng vi dung dch brom. sau phn ng xy ra ton thy c cht kh thot ra v 40 gam brom tham gia phn ng .a) vit phng trnh phn ng xy ra b) tnh thnh phn phn trm th tch mi cht trong hn hpc) t chy ton b th tch kh thot ra sau cho cht kh thu c tc dng vi 100ml dung dch Ca(OH)2 1,25 M. tnh khi lng cht thu c sau phn ng . bit metan ko tc dng vi brom , cc cht kh o iu kin tiu chun what is meant by national project All of the following are true about a cyclical pattern EXCEPT it is ______. a. often combined with long-term trend patterns and called trend-cycle patterns b. often due to multi-year business cycles c. usually easier to forecast than a seasonal pattern due to less variability d. an alternating sequence of data points above and below the trend line Most of the ........... in Britain is used for human habitation. what is filtration? Compare and contrast intensive and extensive physical properties, and give 3 examples of each. Which one of the following always has a debit balance A. Capital accountB. Purchases account C. Sales accountD. Purchases return account The top part of Mars, Inc.'s 2018 balance sheet is listed as follows (in millions of dollars). Current assets: Current liabilities: Cash and marketable securities $ 10 Accrued wages and taxes $ 20 Accounts receivable 40 Accounts payable 30 Inventory 160 Notes payable 40 Total $ 210 Total $ 90 What are Mars, Inc.'s current ratio, quick ratio, and cash ratio for 2018? Munich pact was not signed by If per unit variable cost of a product is Rs.8 and fixed cost is Rs 5000 and it is sold for Rs 15 per unit, profit in 1000 units is.......a.. rs 7000b. rs 2000c. rs 25000d. rs 0 What is the melting pot theory?O A. The belief that each different culture should live in a different partof the United StatesB. The idea that each race should adopt a single culture to separateit from all other racesC. The belief that it is possible for people of many different culturesto live with one another peacefullyD. The idea that the different peoples who have come to the UnitedStates have blended to create a new culture A study conducted by the University of Illinois in the 1950s found that pilots with insufficient instrument flying ability lose control of their airplane in an average of only ________ once they lose outside visual references Lee el consejo que le dio Martn a su prima._[blank]_ la ropa del mes pasado, promocinala por medio de ofertas.Qu opcin completa la oracin correctamente?Si quiere venderSi quieres venderS, quieres queSi quiere que 12) Find the angles between 0o and 360o where sec = 3.8637 . Round to the nearest 10th of a degree:Please show all work Determine whether the following people and events were part of the First Crusade or the Fourth Crusade. Pope Urban II calledfor people to recoverJerusalem fromthe Muslims.Crusaders sackedConstantinople.The Holy Roman Emperorwanted to regain controlof the Byzantine Empire.Crusaders massacredJews in the Rhineland.Crusaders recapturedJerusalem but killed Jews,Muslims, and Christiansin the process.Pope Innocent III hoped toreturn to Jerusalem to freethe city from the Muslims.Fast, please.I will give brainliest, 5 stars, and thanks if it is correct. A cricketer throws a ball sideways with an initial velocity of 30 m/s. She releases the ball from a height of 1.3m. Calculate how far the ball travels before hitting the ground. We are given a weighted coin (with one side heads, one side tails), and we want to estimate the unknown probability pp that it will land heads. We flip the coin 1000 times and it happens to land heads 406 times. Give answers in decimal form, rounded to four decimal places (or more). We estimate the chance this coin will land on heads to which word has the most negative connotation? What can be done to help maintain cardiovascular health? plz plzzz helpp meelook photoplz help asapi will give brainliestplzzz