Consider the Hertzsprung Russell diagram seen here. We can use this diagram to classify stars and determine their characteristics.
The color of a star is determined by its temperature: the hottest stars are blue and the coolest are red. The Sun has a surface
temperature of 5,500°C and it appears yellow. The diagram also indicates that temperature coincides with luminosity: the hotter the
star, the higher the luminosity. You can also tell the size of each star from the graph as the larger the radius, the higher the
temperature and luminosity. Regardless of a star's position in the diagram, the energy that results in high temperatures and the stars
luminosity is generated by what process?
W
A)
nuclear fusion
B)
nuclear fission
gravitational forces of swirling gases
D)
friction generated by gravitational force

Explanation:

4.5×6.022×10²³

27.099×10²³

According to Avogadro's number, there are 27.10×10²³ atoms in  4.5 moles of Al.

Avogadro's number is defined as a proportionality factor which relates number of constituent particles with the amount of substance which is present in the sample.

It has a SI unit of reciprocal mole whose numeric value is expressed in reciprocal mole which is a dimensionless number and is called as Avogadro's constant.It relates the volume of a substance with it's average volume occupied by one of it's particles .

According to the definitions, Avogadro's number depend on determined value of mass of one atom of those elements.It bridges the gap between macroscopic and microscopic world by relating amount of substance with number of particles.

Number of atoms can be calculated using Avogadro's number as follows: mass/molar mass×Avogadro's number.As 1 mole =6.023×10²³ atoms , thus,4.5 moles =4.5×6.023×10²³ = 27.10×10²³  atoms.

Thus, there are 27.10×10²³ atoms in  4.5 moles of Al.

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Answer:

The solid crystals disappeared

Explanation:

When a soluble solid solute is added to water, the solid solute disappears after a little while. The disappearance of this solute indicates that the solute has been dissolved in water.

In this case, blue copper sulphate crystals are added to water, the blue crystals disappear leaving only a blue solution. The disappearance of these blue copper sulphate crystals indicates that the substance has dissolved in water.

Answer:

Explanation:

I can’t explain but this is the answer LOL

Answer:

48 °C

Explanation:

q = 90J

m = 15 g

C = 0.126 J/gºC

q = mct

90 = (15)(0.126)t

t = 47.62 °C = 48 °C

Answer:

Explanation:

Formula

E = m * c * Δt

Δt is what you seek.

Givens

E = 90 joules

m = 15 grams

c   = 0.126

Solution

90 = 15 * 0.126 * Δt         Divide by 15

90/15 = 15/15 * 0.126 * Δt

6 = 0.126 * Δt                  Divide by 0.126

6/0.126 = Δt

47.619 = Δt

Δt = 48 oC

Answer:

Explanation:

A covalent compound is a compound formed by covalent bonds. A covalent bond is formed between two atoms where electrons are shared between the two atoms. This forms a molecule.

What determines whether two elements will form a covalent compound or not is the number of valence electrons present in each of the elements.

Fluorine will form a covalent compound with phosphorous because fluorine has 5 electrons in its outermost shell. It needs 3 more to become stable.

Phosphorous also has 5 valence electrons. It needs 3 more to become stable.

What happens is that 3 atoms of FLuorine combine with one atom of Phosphorus, sharing the valence electrons between themselves. This leads to the formation of the PF3 molecule.

Both the Phosphorous and the Fluorine are now stable.

Answer: Phosphorus

Explanation: since both are non-metals they would both create a covalent bond.

17 × ( 2 × 16 ) = 17 × 32 = 544 grams

___________________________

Answer:

it's A.

Explanation:

have uh good day ma :)))))))

Answer: i need help

Explanation:

Answer:

Alkynes are saturated hydrocarbons

Explanation:

Alkynes are groups of hydrocarbons that have the general formula of {Cn H2n - 2}. They have a triple carbon to carbon bond (C≡C) in their structure. Ethyne (HC≡CH) is the first member of the alkyne series.

Alkynes like alkenes are unsaturated hydrocarbons because of their triple and double carbon bonds respectively. Unsaturated hydrocarbons do not have a complete hydrogen atom in their structural composition. Hence, the statement that "Alkynes are saturated hydrocarbons" is FALSE.

Answer:

600 mL

Explanation:

molarity 1 * volume 1 = molarity 2 * volume 2. So this means 12 * 250 = 3000 and divide that by 5 to get 600 mL.

Answer:

A climate change

Explanation:

the surrounding area would be effected in all ways imaginable, such as change in air, soil, water, plants, animals. and if you eat those said animals those harmful things can transfur into you

Answer: What is the mass of disulfur pentoxide (S2O5)?

Explanation:144.14g/mol

it is held every 4-5 years

Answer:

The tectonic style and viability of modern plate tectonics in the early Earth is still debated. Field observations and theoretical arguments both in favor and against the uniformitarian view of plate tectonics back until the Archean continue to accumulate. Here, we present the first numerical modeling results that address for a hotter Earth the viability of subduction, one of the main requirements for plate tectonics. A hotter mantle has mainly two effects: 1) viscosity is lower, and 2) more melt is produced, which in a plate tectonic setting will lead to a thicker oceanic crust and harzburgite layer. Although compositional buoyancy resulting from these thick crust and harzburgite might be a serious limitation for subduction initiation, our modeling results show that eclogitization significantly relaxes this limitation for a developed, ongoing subduction process. Furthermore, the lower viscosity leads to more frequent slab breakoff, and sometimes to crustal separation from the mantle lithosphere. Unlike earlier propositions, not compositional buoyancy considerations, but this lithospheric weakness could be the principle limitation to the viability of plate tectonics in a hotter Earth. These results suggest a new explanation for the absence of ultrahigh-pressure metamorphism (UHPM) and blueschists in most of the Precambrian: early slabs were not too buoyant, but too weak to provide a mechanism for UHPM and exhumation.

Explanation:

Answer:

5.9 × 10² kJ

Explanation:

When carbon disulfide, CS₂, forms from its elements, heat is absorbed. The corresponding value for the standard enthalpy of formation of carbon disulfide is 117.36 kJ/mol. The thermochemical equation that represents this process is:

C(graphite) + 2 S(s, rhombic) ⇒ CS₂(g)   ΔH°f = 117.36 kJ/mol

117.36 kJ of heat are absorbed when 1 mole of CS₂ is formed. The amount of heat absorbed when 5.0 moles of CS₂ are formed is:

5.0 mol × 117.36 kJ/mol = 5.9 × 10² kJ

Answer:

15.5 moles

Explanation:

Applying,

PV = nRT.................. Equation 1

Where P = pressure, V = Volume, n = number of mole, R = molar gas constant, T = Temperature.

Make n the subject of the equation

n = PV/RT............... Equation 2

From the question,

Given: P = 0.899 atm, V = 425 L, T = 24 °C = (273+24) K = 297 K.

Constant: R = 0.083 L.atm/K.mol

Substitute these values into equation 2

n = (0.899×425)/(297×0.083)

n = 15.5 moles

Answer: A

Explanation:

The correct structure of the name of the compound given is  CH₃CH₂C=CC (CH₃)₃.

Dimethyl hexyne is an organic compound. Its chemical formula is C8H14. The compound hexyne is used to make a complex compound, agrochemical, and pharmaceutical compounds.

Thus, the correct option is A, CH₃CH₂C=CC (CH₃)₃.

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Answer:

a chemical reaction occured

Explanation:

bubbling and fizzing after adding a substance, most offten means a chemical reaction is happening

Answer:

Square

Explanation:

A square is a quadrilateral with r sides the same length

Answer:

4

Explanation:

If I remember correctly, the atomic # will always be the same as the # of electrons

Answer:

1.13 L

Explanation:

First, we have to write the chemical equation for the reaction between ammonia gas (NH₃) and oxygen gas (O₂) to give nitrogen gas (N₂) and water (H₂O), as follows:

NH₃(g) + O₂(g) → N₂(g) + H₂O(g)

Then, we have to balance the equation (we write first the coefficient 2 for NH₃ to balance N atoms, then a coefficient of 3 for H₂O to balance H atoms, and finally 1/3 to balance the O atoms):

2 NH₃(g) + 3/2 O₂(g) → N₂(g) + 3 H₂O(g)

In the balanced equation, we can see that 1 mol of N₂ is produced from 2 moles of NH₃. We convert the moles of NH₃ to grams by using its molecular weight (MW):

MW(NH₃) = 14 g/mol N x 1 + (1 g/mol H x 3) = 17 g/mol

grams of NH₃ = 17 g/mol x 2 = 34 g

Thus, we have the stoichiometric ratio:

1 mol of N₂/2 mol NH₃ = 1 mol of N₂/34 g NH₃

To calculate how many moles of N₂ are produced from 4.0 of NH₃, we multiply the mass by the conversion factor:

4.0 g NH₃ x 1 mol of N₂/34 g NH₃ = 0.1176 moles N₂

Finally, we calculate the liters of N₂ gas by using the ideal gas equation:

PV = nRT ⇒ V = nRT/P

We introduce the data in the equation:

T = 32.00°C + 273 = 305 K

P = 2.6 atm

R = 0.082 L.atm/K.mol (is the gas constant)

n= 0.1176 moles

⇒ V = nRT/P = (0.1176 mol x 0.082 L.atm/K.mol x 305 K)/(2.6 atm)

                     = 1.13 L

Answer:

Deci trebuie sa te aplici cu 2 din3 pe suprafata pamanyului chinez

Explanation:

Deci 1287+2086+2762+7:5

Answer:

los metales alcalinotérreos: berilio (Be), magnesio (Mg), calcio (Ca), estroncio (Sr), bario (Ba) y radio (Ra).

o simplemente llamado grupo 2A

Explanation:

Answer:

0.113 liters

Explanation:

5.41 M / 47.71 moles = 0.113 liters

Answer:

C)12.09 Ampere

Explanation:

V= IR

Where I= current of the system

R= resistance= 0.67 ohm

V= potential difference=8.1 volts

Substitute the values

8.1= I× 0.67

I= 8.1/0.67

=12.09 Ampere

Answer:

The period number on the Periodic table tells you the total number of orbits that the atom will have. In other words, the period number indicates the number of energy levels (or energy orbit) of an atom. For example, 1st period indicates that these elements possess 1 energy shell (or energy orbit).

Explanation:

Answer:

The 2nd one is the one

Explanation:

and it isn't writen out all the way

Answer: 4.48 or 4.47

Answer: f = 760 Hz

Explanation:  speed = frequency · wavelength  v = fλ.

frequency f = v/ λ = 380 m/s / 0.50 m = 760 Hz