Which of the following best describes a mixture? A. A substance that results when another substance is separated into its component parts B. A substance composed of two or more elements chemically combined C. A substance that results when two or more substances combine physically but not chemically D. A particle consisting of two or more atoms chemically combined​

Answer:

2.5 moles

Explanation:

Number of moles = MassMolar mass

= 80⋅g32.06⋅g⋅mol−1 = ??mol

Note that sulfur likely exists in its elemental state as S8. I am perfectly justified in treating sulfur as S. The number of sulfur atoms is the same in each case.

Answer:

all sloped parts

Explanation:

Sloped part of the curve  - all      as this would show a change in T   ( or delta T)

  the flat parts would involve no change in Temp

Answer:

Below

Explanation:

Units of specific heat are   J / (g- °C)

    so to get these units :

             1259 J / (25 g *6.1 °C) = 8.26  J / (g °C)

the equation of the parabola is given as [tex]y = 1/4 (x-6)^2 +1[/tex]. D

Given the focus(6,2) and the directrix, y = 0

Use the formula

[tex]\sqrt{(x-6)^{2} + (y-2)^{2} } }[/tex] = (y - 0)

Find the square of both sides, square root is removed from the side with it and square added on the other side

[tex](x-6)^2 + (y-2)^2 = (y- 0)^{2}[/tex]

Expand the expression and bring all terms to one side

[tex]x^{2} - 6x - 6x + 36 +y^{2} -2y- 2y +4[/tex] = [tex]y^{2} - 0[/tex]

Collect like terms

[tex]x^{2} - 12x -4y + 40 = 0[/tex]

Make 'y' the subject of the formula

[tex]4y = x^{2} - 12x + 40[/tex]

Divide through by 4 and substrate 4 from 40 to give a perfect quadratic equation

[tex]y = 1/4( x^{2} - 12x + 36) + 4[/tex]

1/4 is dividing the quadratic equation [tex]x^2 - 12x +36[/tex]

Then divide factor by 4 to give 1, this is so because of the nature of the options given

[tex]y = 1/4( x^{2} -6x -6x +36) + 1[/tex]

Simplify the expanded quadratic equation

[tex]y = x (x -6) - 6 (x- 6)[/tex], we have [tex](x - 6) ^2[/tex]

Then insert in place into previous equation

[tex]y = 1/4 (x-6)^2 + 1[/tex]

Thus, the equation of the parabola is given as [tex]y = 1/4 (x-6)^2 +1[/tex]

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0.7 mol of H⁺ ions are present in 2.8 l of 0.25 m hydrobromic acid solution.

Hydrobromic acid is a strong acid, we can assume that all acid molecules dissociate completely to yield H+ ions and dissociated anion.

                             Hbr (s) →  H⁺ (aq)  +  Br⁻ (aq)

moles H⁺ = ([tex]2800ml[/tex]) ( [tex]\frac{1L}{1000ML}[/tex])  ([tex]\frac{0.25 mol Hbr}{L}[/tex]) ( [tex]\frac{1 mol H}{1 mol Hbr}[/tex])

               = 0.7 mol

Therefore, 0.7 mol of H⁺ ions is present.

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Answer:

protons and neutrons have different charges but they have approximately the same mass

Answer:

93.5 moles N₂

Explanation:

To find the moles, you need to use the Ideal Gas Law. The equation looks like this:

PV = nRT

In this equation,

-----> P = pressure (atm)

-----> V = volume (L)

-----> n = number of moles

-----> R = constant (0.0821 atm*L/mol*K)

-----> T = temperature (K)

You can plug the given values into the equation and simplify to find moles. The final answer should have 3 sig figs to match the lowest number of sig figs among the given values.

P = 95.0 atm                  R = 0.0821 atm*L/mol*K

V = 224 L                       T = 2773 K

n = ?

PV = nRT

(95.0 atm)(224 L) = n(0.0821 atm*L/mol*K)(2773 K)

21280 = n(227.6633)

93.5 = n

Answer:

93.5 moles N₂

Explanation:

You can plug the given values into the equation and simplify to find moles. The final answer should have 3 sig figs to match the lowest number of sig figs among the given values.

P = 95.0 atm                  R = 0.0821 atm*L/mol*K

V = 224 L                       T = 2773 K

n = ?

PV = nRT

(95.0 atm)(224 L) = n(0.0821 atm*L/mol*K)(2773 K)

21280 = n(227.6633)

93.5 = n

Explanation:

Respiration is the process of oxidation of food materials like glucose, Amino acids, fatty acids to water and carbon dioxide. Respiration does not require any external heat to carry on the process. Combustion is only done by applying external heat to the sugar molecule to burn.

Answer:

alkaline

Explanation:

Lithium reacts intensely with water, forming lithium hydroxide and highly flammable hydrogen. The colorless solution is highly alkalic.

According to the chemical reaction between lithium and water, lithium hydroxide is formed which is a basic substance.

Chemical reactions are defined as changes which occur when a substance combines with another substance to form a new substance.Alternatively, when a substance breaks down or decomposes to give new substances it is also considered to be a chemical reaction.

There are several characteristics of chemical reactions like change in color, change in state , change in odor and change in composition . During chemical reaction there is also formation of precipitate an insoluble mass of substance or even evolution of gases.

There are three types of chemical reactions:

1) inorganic reactions

2)organic reactions

3) biochemical reactions

During chemical reactions atoms are rearranged and changes are accompanied by an energy change as new substances are formed.

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No. Atoms do not get destroyed during reactions.

According to the law of conservation of matter, matters can not be created nor destroyed in any way. Be it during reactions or otherwise.

However, matters can be converted from one form to another during reactions.

Atoms are a form of matter, and thus, cannot be destroyed during reactions.

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Answer:

Calcite

Explanation:

When in contact with hydrochloric acid, calcite releases carbon dioxide gas.

Answer:

a.  P=188mmHg

Explanation:

A gas undergoing a change of volume and pressure at constant temperature (and not changing the number of molecules), follows Boyle's Law:  [tex]P_1V_1=P_2V_2[/tex]

The units of these quantities can be any measure of pressure and volume, so long as long as the units are the same between beginning and ending conditions.

Substitute and solve:

[tex]P_1V_1=P_2V_2[/tex]

[tex](685[mmHg])(131[mL])=P_2(478[mL])[/tex]

[tex]\dfrac{(685[mmHg])(131[mL\!\!\!\!\!\!\!\!\!{--}])}{478[mL\!\!\!\!\!\!\!\!\!{--}]}=\dfrac{P_2(478[mL]\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!{----})}{478[mL] \!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!{----}}[/tex]

[tex]187.730125523[mmHg]=P_2[/tex]

Accounting for significant figures, [tex]P_2=188[mmHg][/tex]

Answer:

The diagram represents the general equation for photosynthesis.

What does the X represent?

Explanation:

Carbon dioxide

Scientific theories are always testable. A theory may be changed as a result of new observations.

A scientific theory is a set of laws, facts and hypotheses that have a complete vision of an aspect of reality.

It is a proposed explanation for a set of observable phenomena.

It allows in this way to organize and understand the observations and to be able to predict or provoke other future observations.

Theories can be modified or improved as more information is collected.

That is, theories can continue to be tested indefinitely, and eventually rejected, if the tests lead to it.  

Therefore, a scientific theory is testable by using a research method.

As mentioned, any theory can be tested or rejected as more information is collected.

This information to prove or reject theories are interpretations of observable facts, which generates new statements or allows to accept those already included in the theory.

Then, a theory may be changed as a result of new observations.

Finally, scientific theories are always testable. A theory may be changed as a result of new observations.

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Answer:

testable & new observations

Explanation:

Answer: [tex]\text{CH}_{4}+2\text{O}_{2} \longrightarrow \text{CO}_{2}+2\text{H}_{2}\text{O}[/tex]

Explanation:

The unbalanced equation is

[tex]\text{CH}_{4}+\text{O}_{2} \longrightarrow \text{CO}_{2}+\text{H}_{2}\text{O}[/tex]

Balancing this equation, we get:

[tex]\boxed{\text{CH}_{4}+2\text{O}_{2} \longrightarrow \text{CO}_{2}+2\text{H}_{2}\text{O}}[/tex]

Moles of benzene

moles of CCl_4

Now

[tex]\\ \rm\Rrightarrow \chi_{C_6H_6}[/tex]

[tex]\\ \rm\Rrightarrow \dfrac{\chi_{C_6H_6}}{\chi_{sol^n}}[/tex]

[tex]\\ \rm\Rrightarrow \dfrac{0.8}{0.8+0.2}[/tex]

[tex]\\ \rm\Rrightarrow \dfrac{0.8}{1}[/tex]

[tex]\\ \rm\Rrightarrow 0.8[/tex]

Answer:

Chemical formulas tell you how many atoms of each element are in a compound, and empirical formulas tell you the simplest or most reduced ratio of elements in a compound. If a compound's chemical formula cannot be reduced anymore, then the empirical formula is the same as the chemical formula.

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Answer:

0.000019952mol/dm3

Explanation:

pH=-log(H+)

4.7= -log(H+)

log(H+)=-4.7

(H+)=10*-4.7=0.000019952

Answer:

chemical energy is the energy of a chemical substance that is stored in the bonds of chemical compounds and is released when they undergo a chemical reaction and transform into another substance

Answer:

Because of gravity and as a result, created planets and stars.

(Likely by a nearby supernova shockwave also)

Although I'm not an expert, I seem to recall reading that solar systems often begin with clouds of unorganized matter measuring 20 parsecs (65 light years) across. Most of them are hydrogen molecules. The pressure required to hold the molecules together increases with temperature, but because the typical temperature is around 12 k, the pressure is negligible. It originates from the gravity of the cloud itself. Material from novas, colliding neutron stars, and high-speed material jets emerging from stars and black holes all contribute to the continuous enrichment of such clouds. That adds those heavy elements—like gold—that can only be produced by the rapid neutron capture (rNC) process as opposed to the simple nuclear fusion process (slow neutron capture). These clouds spontaneously emerge from floating pieces of material, hold together for millions of years, and eventually disperse. A component of the cloud condenses along the route for a variety of causes, including localized concentrations of greater density or shock waves from supernovae. Unbalances in the cloud lead it to split up when condensation takes place. Then those fragments shatter once again, leaving you with barely enough for a solar system. It would have been within 3.5 light years of the initial cloud for our galaxy. The contraction up to this point has been isothermal, which means that heat is being radiated so quickly that temperature stays mostly unchanged. The creation of a Bonnor-Ebert sphere comes next. Although such zones frequently appear in photographs in a faint manner, this is only a hypothetical area in which there is a certain amount of mass. The First Hydrostatic Core is located here (FHSC or First Core). The First Core can be imagined as a pre-proto Sun with an interior temperature of roughly 300 k and a radius of 1 AU (the same as the Earth's orbit) (26.85 C or 80.33 F). Although it first begins off chilly, it ultimately warms up to 300 k and then grows even hotter over the course of years. The friction of falling materials and adiabatic contraction provide the heat (the kind that makes things hotter). Hydrogen molecules start to break down into atomic hydrogen, which is more dense and falls to the center, at temperatures between 1500 k and 2000 k, on average. Eventually, the atomic hydrogen coalesces into a protostar-sized Second Core. Because the entire system is rotating swiftly and because momentum is being lost in some areas owing to gas shooting off, an accretion disk has already formed. Although in our instance it would have also been a protoplanetary disk, the disk is a protostellar disk. The protostar is regarded as a star until it becomes hot and brilliant enough to begin ejecting the gas and dust. (Prior to it, infalling gas and dust are still adding mass to the protostar.)

In the nebular hypothesis, the collapse of the nebula is believed to have been triggered by a disturbance or shock wave, such as a nearby supernova explosion or the gravitational influence of a passing star or gas cloud.

This disturbance caused the nebula, which was a large and diffuse cloud of gas and dust in space, to start collapsing under the force of its own gravity. As the nebula contracted, its particles came closer together, and the conservation of angular momentum caused it to spin faster.

The collapse and spin eventually led to the formation of a rotating protostellar disk at the center, which eventually evolved into a young star, while the surrounding material formed planets and other celestial bodies through accretion and gravitational attraction.

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Answer:

it was more acidic

Explanation:

changing the pH of the solution and making it more acidic results in the color of the solution changing it from blue to yellow

solution is Bromothymol blue

in a ph below 6 it turns yellow because

a ph below 6 is acidic

a ph above 7.6 its blue because

a ph above 7.6 is basic

Bromothymol blue is made in a basic solution, so it starts out as blue, thus the name 'blue'. It changes to yellow in acidic conditions

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wikipedia

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Answer:

their valence electrons are free roaming

This happens because the beaker is open.

The Law of Mass Conservation says that in a close system all the mass and energy should be the same.

If the system is open, as in the case, we can have loss of mass, due to formation of gas, that will leave the beaker to the environment, and we can also have loss of energy, because the system will exchange the energy, as heat, with the environment, causing a loss on the total energy.

Answer:

Its C its C its C

Explanation:

i dislike expert verifeid beacause he wont say C

Answer:

The Oxygen

Explanation:

When fire is covered, it goes out due to the lack of oxygen to maintain itself.

The limiting reactant in the experiment of the burning candle is oxygen.

A limiting reactant is a reactant which determines the amount of product that ca be formed in a given reaction.

The limiting reactant is always used up in a reaction, after which the reaction stops.

In the experiment of the burning candle, covering the candle with the glass prevents more oxygen from taking part in the reaction.

Therefore, the limiting reactant is oxygen.

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Answer: a. The particles in the gas are moving faster than the particles in the liquid

Answer:

It has protons, neutrons and electrons

Option C is the correct answer

Hence , LHS = RHS

A balanced equation obey the law of conservation of mass. According to this law mass can neither be created nor be destroyed. Among the given options, the balanced equation is 2H₂ + O₂ → 2H₂O. The correct option is C.

A chemical equation in which the number of atoms of reactants and products are equal on both sides of the equation is defined as the balanced chemical equation. The numbers which are used to balance the equation are called the coefficients.

The coefficients are generally placed in front of the formulas. The substances on the left hand side are called the reactants and the substances on the right hand side are called the products.

Here the balanced equation is:

2H₂ + O₂ → 2H₂O

The number of 'H' and 'O' atoms are equal on both sides.

Thus the correct option is C.

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2.23 moles of propane react when 294 g of CO₂ is formed .

Moles is a unit which is equal to the molar mass of an element.

A reaction is given

C₃H₈ +50₂ → 3CO₂ + 4H₂O

Grams of CO₂ formed = 294 gm

In moles = 294 /44 = 6.68 moles.

Let x be the moles of C₃H₈ is x

Mole ratio of CO₂ to C₃H₈ = 3 : 1

so

6.68 /x = 3/1

x = 6.68 /3 = 2.23 moles

Therefore 2.23 moles of propane react when 294 g of CO₂ is formed .

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Answer:

ionic bond

Explanation:

Answer:

Ionic bonding

Explanation:

Salt    Na+Cl-       is an example