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Answer:

CH

Explanation:

Polystyrene is composed only by C and H.

We can calculate the number of C moles contained in the original sample mass (0.00215 g), using the produced mass of CO₂:

As 1.65x10⁻⁴ moles of CO₂ were produced, in the polystyrene sample there were 1.65x10⁻⁴ moles of C.

Now we calculate how many moles of H₂O were produced:

The number of H moles produced is double the amount of H₂O moles, so in the polystyrene sample there were 1.64x10⁻⁴ moles of H.

The number of C and H moles are the same, this means the empirical formula is CH.

Answer: x + 10y - 10z is the answer

Explanation:

Answer:

Adding fluoride to the water supply reduces the incidence of tooth decay. Fluoride protects teeth from decay by demineralization and remineralization. Too much fluoride can lead to dental fluorosis or skeletal fluorosis, which can damage bones and joints.

Explanation:

N/A

Answer:

Refracted (refraction) – the bending of transmitted light as it travels across the boundary of one material into another material in which it's speed is different. Unlike diffraction, this change in direction of light occurs because light is changing its speed in the different substances in it traveling in.

Explanation:

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Answer:

Because their cells duplicate inside of you not normally!

Explanation:

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Kinetic energy is the amount of energy present in the object due to motion. It is required by the body for action and motion. The kinetic energy of the car is 34385J.

Kinetic energy is a type of energy that is directly proportional to the mass of the object and the square of the velocity. The formula for the kinetic energy can be given as,

[tex]\rm KE = \dfrac{1}{2}mv^{2}[/tex]

Here,

Mass of the car (m) = 130 kg

Velocity of the car (v) = 23 m/s

Substituting values in the equation:

[tex]\begin{aligned}\rm KE &= \dfrac{1}{2}\rm mv^{2}\\\\&= \dfrac{1}{2}\times 130\times (23)^{2}\\\\&= 34385\;\rm J\end{aligned}[/tex]

Therefore, 34385J is the kinetic energy of the car.

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Answer:

The answer is C!

Explanation:

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Answer D

Explanation: did the quiz ψ(｀∇´)ψ

The item that is significantly made up of one or more molecules is hydrogen. Thus, the correct option for this question is B.

A molecule may be defined as a group of one or more atoms that are held together by numerous chemical bonds. It is the smallest particle of a substance that has all sorts of physical and chemical properties of that substance.

Among the given options, gold and neon are the elements, while salt is a compound. Hydrogen is a gas of diatomic molecules bearing the formula H2. It is colorless, tasteless, odorless, non-toxic, and highly combustible. Hydrogen in its molecular form is more common.

A hydrogen molecule is one of the simplest possible molecules which significantly consists of two protons and two electrons. These protons and electrons are remarkably held together by electrostatic forces.

Therefore, the item that is significantly made up of one or more molecules is hydrogen. Thus, the correct option for this question is B.

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Answer:

The fourth one- bromo trifluoro methane

Explanation:

Answer:

D

Explanation:

I believe the answer is the 4th option, bromo-trifluoro-methane

Answer: 0.45 moles of water are needed to produce 0.075mol of glucose.

Explanation:

The balanced chemical reaction is:

[tex]6CO_2(g)+6H_2O(l)\rightarrow C_6H_{12}O_6(aq)+6O_2(g)[/tex]

According to stoichiometry :

1 mole of glucose require = 6 moles of [tex]H_2O[/tex]

Thus 0.075 moles of glucose require = [tex]\frac{6}{1}\times 0.075=0.45[/tex] moles of [tex]H_2O[/tex]

0.45 moles of water are needed to produce 0.075mol of glucose.

Answer: 9.46

Explanation: in LiOH solution concentration of OH- ions is 2.88·10^-5 M

And pOH = -log( 2.88·10^-5 M) = 4.54. Because PH + pOH = 14.00

Then pH = 14-4.54

Answer:

The stratosphere

Explanation:

Answer: Cut the card borad

Explanation:

Answer:

chemical reaction hope this helps ;)

Explanation:

Answer:

phase change always has two phases in contact during the change. melting => solid & liquid; evaporation (boiling) => liquid & vapor. If only one phase is present, then phase change is not occurring. Also, when two phases are in contact, no temperature changes occur. Only the pure phase demonstrates temperature change when measured. Example, when ice is added to water, at thermal equilibrium (temp = 0°C) the water temp will not continue to change. Only when all the ice has melted will the water temperature demonstrate a measured temperature change.

Explanation:

Answer:

The climate has been caused by many natural factors including changes in the sun emissions from volcanoes variations in Earth's orbit and levels of carbon dioxide. Global climate change has typically occured very slowly over thousands or millions of years .The three causes of the Earth's climate are

these are the causes of the Earth's climate.

Climate is a average weather in a given area for a long period of time is called a climate

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Answer: The name of the super continent that existed millions of years ago.

Explanation:

Our continents as they exist today were once joined together into a super continent known as Pangea. Over the millennia, the land masses broke off and drifted away creating the location of the continents we know today.

(つ ^‿^ )つ Hey there!

Answer → Is the second answer, The name of the super continent that existed millions of years ago.  

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Answer:

32.8%

Explanation:

All of the Pb⁺² species precipitated as lead(II) cromate, PbCrO₄ (we know this as excess K₂CrO₄ was used).

First we convert 0.130 g of PbCrO₄ into moles, using its molar mass:

There's 1 Pb⁺² mol per PbCrO₄ mol, so in total 4.02x10⁻⁴ moles of Pb⁺² were in the ethanoate sample.

We convert those 4.02x10⁻⁴ moles of Pb into grams:

Finally we calculate the percentage composition of Pb:

Explanation:

molar mass of tetranitrogen dicarbide S4N4= 4×32+4×14

128+56

184 g/mol

no.of moles =given mass/ molar mass

3400= given mass / 184

3400×184 =given mass.

625600 g

Answer:

As you cool a matter to absolute zero, their kinetic energy reduces significantly and the molecules slows down and begins to aggregate together. ... As heat is added, the molecules gain more kinetic energy. This shown in their increase motion. When heat is withdrawn, the particles slows down hope this helped

The gas that has the least collisions between its particle is helium at 20° C. The correct option is A.

Collision is a term used when two particles or object collides or clash and there is an exchange or transformation of energy between them. When a collision happens, the force is exerted on each other.

Helium is the second most abundant element present in the atmosphere. It is the lightest gas and its particle collides when there is an increase in the temperature.

Thus, the correct option is A. Helium at 20° C., regarding the collision of particles between its particles.

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The physical property that is characteristic of all of the elements in the group located in the rightmost column of the periodic table is the gaseous state at room temperature.

Physical properties may be defined as those properties of matter that do not involves any chemical manifestation or appearance within the element. These properties are measurable and state the alteration between momentary states. Some examples of physical properties are as follows:

The groups located in the rightmost column of the periodic table are known as the halogens and the noble gases. These elements are typically gaseous in phase at room temperature. Apart from this, halogens also have high electronegativities because these elements have seven electrons in their valence electrons.

Therefore, the gaseous state at room temperature is the physical property that is characteristic of all of the elements in the group located in the rightmost column of the periodic table.

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Answer:

Lake pontchartrain

Explanation:

Answer:

0.3529moles

Explanation:

no of moles =mass ÷molar mass

molar mass =17+17

=34

12÷34

=0.3529moles

According to the mole concept, the number of moles of molecules in a 12.0-gram sample of Cl₂ is equal to 0.169  moles.

Mole is defined as the unit of amount of substance . It is the quantity measure of amount of substance of how many elementary particles are present in a given substance.

It is defined as exactly 6.022×10²³ elementary entities. The elementary entity can be a molecule, atom ion depending on the type of substance. Amount of elementary entities in a mole is called as Avogadro's number.

It is widely used in chemistry as a suitable way for expressing amounts of reactants and products.For the practical purposes, mass of one mole of compound in grams is approximately equal to mass of one molecule of compound measured in Daltons. Molar mass has units of gram per mole . In case of molecules, where molar mass  in grams present in one mole  of atoms is its atomic mass.Number of moles is mass/molar mass= 12/70.90=0.169 moles.

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Answer:

The main universal indicator is in the form of a solution and are thymol blue , methyl red , bromothymol blue and phenolphthalein this mixture is important because each component loses or gains protons depending upon the acidity of the solution being tested .

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Answer:

28g

Solution. Hence, 2 moles of nitrogen atoms weigh 28g.