An element is

A) made of only one kind of atom.

B) made of compounds from the periodic table.

C) made of different atoms physically combined together.

D) made of different kinds of atoms chemically combined.

Answer:

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Explanation:

gtryijdohuygfvbhgfy

Answer:

1: C

2: A

3: B

4: I

5: G

6: H

Explanation:

Please don't crucify me if I'm wrong ;-;

Answer: i think it is 144.16

Explanation:

Answer shallow ocean

Explanation:

i think

Answer:

4.92L

Explanation:

Given parameters:

Initial pressure  = 891mmHg

Initial temperature  = 84°C  = 84 + 273  = 357k

Initial volume  = 5.61L

New temperature  = 40°C   = 273 + 40  = 313k

Unknown:

New volume  = ?

Solution:

Since we are dealing with constant pressure condition, we apply charles's law.

It states that the volume of a fixed mass of gas varies directly as its absolute temperature if the pressure is constant.

    Mathematically ;

         [tex]\frac{V1}{T1}[/tex]    = [tex]\frac{V2}{T2}[/tex]  

V1 is the initial volume                     V2 is the new volume

T1 is the initial temperature             T2 is the new temperature

   [tex]\frac{5.61}{357}[/tex]   = [tex]\frac{V2}{313}[/tex]  

           V2  = 4.92L

Answer:

6.944 liters of O₂ at STP will react with 8.7 grams of C₂H₄ to form CO₂ and H₂O.

Explanation:

The balanced reaction is:

C₂H₄ + 3 O₂ ⇒ 2 CO₂ + 2 H₂O

Being the molar mass of the elements:

Then the molar mass of compound C₂H₄ is:

C₂H₄= 2*12 g/mole + 4*1 g/mole= 28 g/mole

By stoichiometry of the reaction (that is, the relationship between the amount of reagents and products in a chemical reaction), 1 mole of C₂H₄ acts. Then, being the mass of a mole of a substance, which can be an element or a compound, 1 mole of C₂H₄ is 28 g, which is the amount of mass that reacts in this case.

Then be able to apply the following rule of three: if by stoichiometry 28 grams of C₂H₄ react with 3 moles of O₂, 8.7 grams of C₂H₄ with how many moles of O₂ do they react?

[tex]moles of O_{2} =\frac{8.7 grams ofC_{2} H_{4}*3 moles of O_{2} }{28grams ofC_{2} H_{4}}[/tex]

moles of O₂= 0.31  

The STP conditions refer to the standard temperature and pressure. Pressure values at 1 atmosphere and temperature at 0 ° C are used and are reference values for gases. And in these conditions 1 mole of any gas occupies an approximate volume of 22.4 liters.

Then we can apply the following rule of three: if by definition of STP 1 mole occupies 22.4 L, 0.31 moles how much volume will it occupy?

[tex]volume=\frac{0.31 moles*22.4 L}{1 mole}[/tex]

volume= 6.944 L

6.944 liters of O₂ at STP will react with 8.7 grams of C₂H₄ to form CO₂ and H₂O.

The volume of O₂ at STP that will react with the given C₂H₄ is 20.8 L

First, we will determine the number of moles of O₂ required.

From the given balanced chemical equation,

C₂H₄ + 3O₂ → 2CO₂ + 2H₂O

This means

1 mole of C₂H₄ is required to react completely with 3 moles of O₂

Now, we will determine the number of moles of C₂H₄ present

Mass of C₂H₄ = 8.7 g

Using the formula

[tex]Number\ of\ moles = \frac{Mass}{Molar\ mass}[/tex]

Molar mass of C₂H₄ = 28.05 g/mol

∴ Number of moles of C₂H₄ = [tex]\frac{8.7}{28.05}[/tex]

Number of moles of C₂H₄ = 0.31016 mole

Since

1 mole of C₂H₄ is required to react completely with 3 moles of O₂

Then,

0.31016 mole of C₂H₄ will react completely with 3 × 0.31016 mole of O₂

3 × 0.31016 = 0.9305 mole

∴ Number of moles of O₂ required is 0.9305 mole

Now, for the volume of O₂ at STP that will react

Since 1 mole of a gas occupies 22.4 L at STP

Then,

0.9305 mole of O₂ will occupy 0.9305 × 22.4 L at STP

0.9305 × 22.4 = 20.8432 L

≅ 20.8 L

Hence, the volume of O₂ at STP that will react with the given C₂H₄ is 20.8 L

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Answer:

Mass = 114.5 g

Explanation:

Given data:

Mass of zinc = 55 g

Mass of ZnCl₂ produced = ?

Solution:

Chemical equation:

Zn + 2HCl     →      ZnCl₂ + H₂

Number of moles of Zn:

Number of moles = mass/molar mass

Molar mass of Zn = 65.4 g/mol

Number of moles = 55 g/  65.4 g/mol

Number of moles = 0.84 mol

Now we will compare the moles of Zn and zinc chloride,

               Zn           :          ZnCl₂

                1             :           1

              0.84        :          0.84

Mass of ZnCl₂:

Mass = number of moles × molar mass

Molar mass of ZnCl₂= 136.3 g/mol

Mass =  0.84 mol × 136.3 g/mol

Mass = 114.5 g

Answer:

it runs the risk of triggering earthquakes. releases harmful gases

The molecular formula of a compound gives the actual number of atoms of various elements present in one molecule of the compound. The molecular mass is 92 g/mol. The correct option is C.

The empirical formula of a compound can be defined as the formula which gives the simplest whole number ratio of atoms of various elements present in one molecule of the compound.

The molecular formula of a compound is a whole number multiple of its empirical formula.

Molecular formula = n × Empirical formula

The value of 'n' can be obtained from the relation:

n = Molecular mass / Empirical formula mass

Here the value of n = 2. Then,

Molecular mass = n × Empirical formula mass

Empirical formula mass of NO₂ = 45.8 g

2 × 45.8 = 91.6 ≈ 92 g/mol

Thus the correct option is C.

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Answer:

[tex]Distance = 40km[/tex]

Explanation:

Given

[tex]Speed = 80km/hr[/tex]

[tex]Time = 0.5hr[/tex]

Required

Determine the distance covered

Distance is calculated as:

[tex]Distance = Speed * Time[/tex]

Substitute values for Speed and Time

[tex]Distance = 80km/hr * 0.5hr[/tex]

[tex]Distance = 80km * 0.5[/tex]

[tex]Distance = 40km[/tex]

Hence, you travelled 40km

Answer:

It is a Physical change, have a great day :)

Explanation:

A chemical change is a permanent change. A Physical change affects only physical properties i.e. shape, size, etc. ... Some examples of physical change are freezing of water, melting of wax, boiling of water, etc. A few examples of chemical change are digestion of food, burning of coal, rusting, etc.

Answer:

B

Explanation:

Answer:

A covalent bond is a chemical bond that involves the sharing of electron pairs between atoms. These electron pairs are known as shared pairs or bonding pairs, and the stable balance of attractive and repulsive forces between atoms, when they share electrons, is known as covalent bonding.

Explanation:

I hope this helps

Answer:

A) Abosrbed

Explanation:

The change is endothermic, meaning the material absorbs energy when it changes its phase from a solid to a liqiud.

Answer:

2 hydrogen and 1 oxygen

Explanation:

H2O

Hydrogen has the coefficient so you multiply 1 by 2 and it equals 2

Oxygen does not have any sub or coe so its automatically 1

Answer:

I just looked up the types of matter energy has.

Explanation:

I believe the answer is D.

Sally's list of matter that have energy is not complete as all the types of matter have energy as all matter have mass , and mass and energy are related, so she should have added gases and solids to her list.

Matter in chemistry, is defined as any kind of substance that has mass and occupies space that means it has volume .Matter is composed up of atoms which may or not be of the  same type.

Atoms are further made up of sub atomic particles which are the protons ,neutrons and the electrons .The matter can exist in various states such as solids, liquids and gases depending on the conditions of temperature and pressure.

The states of matter are inter convertible into each other by changing the parameters of temperature and pressure.

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Answer:

a. HF

Explanation:

Answer:

See explanation

Explanation:

The reaction between alcohol and acidified potassium dichromate  is a redox reaction. This reaction can be used to detect a drunken driver.

Alcohols can be oxidized to aldehydes, ketones and carboxylic acids depending on the structure of the alcohol. Primary alcohols yield adehydes and carboxylic acids while secondary alcohols are oxidized to ketones.

The colour of the acidified potassium dichromate turns from orange to green when exposed to alcohols from the breath of a drunken driver.

Answer:

2 moles

Explanation:

1.9982182553889358 real number but round up to 2

Answer:

Apollo 11 made a capsule landing

Explanation:

Answer: i don’t know what type of landing you mean

Explanation:

They did a lunar landing then reentry and then capsule landing.

Answer:

50 g

Explanation:

Please brainiest

Answer:

0.1mole

Explanation:

Given parameters:

Pressure = 0.0884atm

Temperature  = 6°C  = 6 + 273  = 279K

Volume occupied  = 26.5L

Unknown:

Number of moles  = ?

Solution:

To solve this problem, we are going to use the ideal gas equation:

           PV  = nRT

P is the pressure

V is the volume

n is the number of moles

R is the gas constant  = 0.082atmLmol⁻¹k⁻¹

T is the temperature.

  Insert the parameters and solve for n;

     0.084 x 26.5  = n x 0.082 x 279

              n  = 0.1mole

Answer:

the molecules are moving more quickly

Explanation:

The  relationship between temperature and pressure is explained using the kinetic theory of matter.

As the temperature of the gas is increased, the molecules have a greater kinetic energy. This increased energy of the gas molecules make the collision between the molecules and with the walls of the container more rapid.

The correct option is;

the molecules are moving more quickly

Answer:

470.4N

Explanation:

Given parameters:

Mass of Stephanie  = 48kg

Unknown:

Force she exerts while falling to the ground  = ?

Solution:

The force she exerts is her weight;

  Weight  = mass x acceleration due to gravity

  Now insert the parameters ands solve ;

  Weight  = 48 x 9.8 = 470.4N

Answer:

shivering is a natural bodily response, the body is trying to heat itself up by moving around.

There are 1.93 x 10²⁴ particles

Given

3.2 moles of Neon gas

Required

Number of particles

Solution

The mole is the number of particles(molecules, atoms, ions) contained in a substance  

1 mol = 6.02.10²³ particles

Can be formulated

N=n x No

N = number of particles

n = mol

No = Avogadro's = 6.02.10²³

So the number of particles for 3.2 moles :

N = 3.2 x 6.02.10²³

N = 1.93 x 10²⁴

or

we can describe it using Avogadro's number conversion factor

[tex]\tt 3.2~moles\times \dfrac{6.02\times 10^{23}}{1~mole}=1.93\times 10^{24}[/tex]

Answer:

NaCl and Br2

Explanation:

Edge 2020

Answer:

The Answer is C: Na and Br3

Explanation: