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4 years ago

If the sentence is true, write true. If the sentence is false , replace the underlined word to make the sentence true.

Chemistry

1 answer:

ivann1987 [24]4 years ago

3 0

1. False

Elements bond to form compounds.

Consider that compounds are essentially clumped up atoms. Knowing this, we know that atoms don’t separate, but rather combine in order to make compounds.

2. True

3. False

Atoms cam lose or gain electrons to form ionic bonds.

When at atom doesn’t have enough electrons to become stable, it will either give or take electrons from another atom in order to become stable. However, because of the fact that the atoms become oppositely charge, they attract each other, thus forming an ionic bond

-T.B.

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A plasma-screen TV contains thousands of tiny cells filled with a mixture of Xe, Ne, and He gases that emits light of specific w

alisha [4.7K]

Answer:

(a) 1.77*10^15 Xe atoms

(b) 2.10*10^16 Ne atoms

Explanation:

Total V = 0.900 mm * 0.300mm * 10.0mm

Total V = 2.7mm cubed

Converting cubed to litres:

2.7mm cubed = 2.7 * 10^-6 Liters

Converting pressure from torr to atm,

(500 torr) * (1 atm ÷ 760 torr) = 0.6578947368 atm

Room temperature is assumed to be 21 degrees celcius, or 294.15 Kelvin

Applying Ideal Gas Equation:

PV = nRT

Therefore, n = PV ÷ RT,

n = [(2.7*10^-6 Liters)(.6578947368 atm)] ÷ [(0.08206)(294.15)]

n = 7.359017079 * 10^-8

Therefore, the total moles present in plasma is 7.359017079 * 10^-8.

(a) To find Xe atoms,

Multiply the total moles present by 4 percent. Therefore,

(7.359017079 * 10^-8)(.04) = 2.943606832*10^-9,

this value gives you Xe moles.

Then multiply by Avogadro's constant:

[(2.943606832*10^-9)(6.022*10^23)] = 1.77*10^15 Xe atoms

(b) and (c) are the same.

Using the total moles number we found in the beginning and minus the number of moles for Xe.

We have:

7.359017079 * 10^-8 - 2.943606832*10^-9 = 7.064656396*10^-8

And Since Ne and He are in a 1:1 ratio, divide this number by two.

We have:

7.064656396*10^-8 ÷ 2 = 3.532328198*10-8 moles

By multiplying this number by Avogadro's number we get atoms:

[(3.532328198*10-8 moles)(6.022*10^23)] = 2.10*10^16

Therefore, the answer for both (b) and (c) is 2.10*10^16.

4 0

3 years ago

What type of wave is sound? a.longitudinal b.surface c.light d.transverse

Harrizon [31]

Sound waves are
a.longitudinal.

4 0

3 years ago

Drag each item to indicate whether it is related to Aristotle's or Ptolemy's model of the solar system, or to both. Some items m

Romashka-Z-Leto [24]

Answer:

Aristotle's Model :

geocentric

planets fixed on nested spheres

Ptolemy's model:

geocentric

planets fixed on epicycles

accurately predicted the positions of the planets

Explanation:

Let's begin by the fact both models are geocentric and make a brief explanation of them:

Aristotle's Model :

Aristotle built his model based on observations and philosophical assumptions, not on measurements or calculations, then he mistakenly thought the Earth was the center of the universe.

So, according to this model, the universe was spherical and finite, with the Earth immobile at its center, composed of the four fundamental elements (made up of spherical layers): ground, water, air and fire; and the Sun along with the fixed planets in their respective concentric spheres (also called nested spheres) revolving around the Earth.

Ptolemy's model:

Ptolemy's model of the universe was also geocentric, placing the Earth motionless in the center of the known universe and was the accepted model for a long time during the Middle Ages.

In this sense, ccording to Ptolemy's model of the universe our planet remains stationary while the other planets, the Moon and the Sun describe complicated orbits around it (called epicycles).

However, this model predicted with an acceptable accuracy for that time the motion of the known planets, until Copernicus appeared with the revolutionary Heliocentric model.

5 0

3 years ago

10. How do liquid water,ice, and water vapor differ from one another?

musickatia [10]

A) They are different states of matter.

6 0

3 years ago

Read 2 more answers

Sugar is stirred into water tp form a solution what names to we give to the sugar and water

Nina [5.8K]

Your answer would be, Sugar is the solute, and water is the solvent. a solution is the mixture of two, or more substances.

Hope that helps!!!

7 0

4 years ago