What’s clues indicate that a chemical reaction has occurred?

Answer:chlorofluorocarbons (CFCs) could deplete Earth's atmospheric ozone layer, which blocks the sun's damaging ultraviolet rays. When the scientists reported their findings in 1974, CFCs were widely used as refrigerant gases and as propellants in aerosol sprays

Explanation:

Answer:

vigorous

Explanation:

As you go down group one of the periodic table, the reactions become and more vigorous.

The material that has been widely used in casting has been copper. Thus, option C is correct.

Casting has been the process of molding the liquid into a specific shape with the mold. The casting involves the heating of elements and converting them into liquid. The liquid has been poured into the mold and cooling results in the casted material.

The casted material has been selected based on the boiling temperature, cooling temperature, resistivity, cost-effectiveness, and damping ability.

The material that has been consisted of these characteristics has been copper. Thus, copper has been commonly used for casting. Thus, option C is correct.

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NaCl - Chlorine has an outer shell with 7 electrons it wants to gain from the Sodium to become stable, whereas the Sodium wants to lose an electron to become stable.

Answer:

I'm pretty sure its just the mass of the sample divided by the molar mass

for example if I had like 7g of carbon and wanted to find the moles, I would divide the mass I have (7g) by the molar mass (the atomic mass value on your periodic table, in this case for carbon it would be 14g)

moles = [tex]\frac{mass}{molarmass} = \frac{7}{14} = 0.5\ moles[/tex]

Hope this helped

Answer:

Silicon (Si)

Explanation:

Add the protons and neutrons mass to get the nucleus mass. Then you get number 14 and 28. looking at the periodic table we can see this matches silicon's atom mass and electron number

Answer:

Fossil fuels like coal, oil and natural gas supply 80 percent of the world’s energy to warm homes, charge devices and power transportation. They are also the primary human source of greenhouse gas emissions. Stanford scientists broadly agree that curtailing our use of fossil fuels would have significant benefits like improving health and reducing the number and severity of natural disasters, but it’s not yet clear what can replace them.

Explanation:

Answer:

1,4 mol

Explanation:

2 mol of Al reacts with 3 mol of FeO so for 2.1 mol of FeO you need 2 x 2.1 / 3 = 1.4mol

Answer:

Slimy Feel

Explanation:

Acid usually doesn't have a Slimy Feel to it.

Answer:

To write a chemical equation, the reactants should be written on the left, and the products should be written on the right and the coefficients should be written next to the symbols of entities to indicate the number of moles of a substance produced used in the chemical reaction.

Answer:

Yes

Explanation

I learned it in science class

Answer: LOUDER

Explanation:

. A larger amplitude means a louder sound, and a smaller amplitude means a softer sound.

Answer: C

Explanation: This is because of a nice thing called guessing

In case of a shortage in petroleum and natural gas, a company should find a way to make nylon without using natural resources.

Nylon is a very important material used in numerous applications. As a result of this, the demand for nylon as a raw material has genuinely been on the high side ever since.

However, nylon production depends on petroleum and natural gas. It is possible that there could be a shortage of these resources since they are obtained from the environment. In such cases, a company should  find a way to make nylon without using natural resources.

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Answer:

identify a different natural resource that nylon could be made from

Explanation:

I just did this question

Answer:

hello

Explanation:

Explanation:

Mass of bomb calorimeter, m = 1.5 kg = 1500 g

Temperature change of calorimeter, ΔT = - 0.985 K

Specific heat of calorimeter, c = 2.52 J/g K

To Find:

The heat of reaction for this system

Calculation:

The heat of reaction can be calculated by the given formula:

Q = mcΔT

⇒ Q = 1500 × 2.52 × (- 0.985)

⇒ Q = - 3723.3 J       (-ve sign shows heat is given by calorimeter)

- So the heat of reaction is -3723.3 J or -3.7233 kJ

Taking into account the definition of calorimetry, the heat of reaction for the system is  -3,723.3 J or -3.7233 kJ.

In first place, calorimetry is the measurement and calculation of the amounts of heat exchanged by a body or a system.

In this way, between heat and temperature there is a direct proportional relationship.

The constant of proportionality depends on the substance that constitutes the body and its mass, and is the product of the specific heat by the mass of the body.

So, the equation that allows to calculate heat exchanges is:

Q = c× m× ΔT

where Q is the heat exchanged by a body of mass m, made up of a specific heat substance c and where ΔT is the temperature variation.

In this case, you know:

Replacing in the expression to calculate heat exchanges:

Q= 2.52[tex]\frac{J}{gK}[/tex]× 1500 g× (-0.985 K)

Solving:

Q= -3,723.3 J= -3.7233 kJ

Negative sign shows heat is given by calorimeter.

In summary, the heat of reaction for the system is  -3,723.3 J or -3.7233 kJ.

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The bond angle obtained based on the geometry of the molecule alone is known as the predicted bond angle.

When a compound is formed, the less electronegative atom in the compound is called the central atom in the molecule. The angle formed by the nuclei of two surrounding atoms with the nucleus of the central atom in a structure is called a bond angle.

The bond angle is usually based on the geometry of the molecule. The expected geometry can be deviated for certain reasons such as the presence of lone pairs on the central atom in the molecule. The bond angle obtained based on the geometry of the molecule alone is known as the predicted bond angle.

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The number of times the percentage of attacks on the dark-colored mouse is greater than the percentage of attacks on light-colored mouse is four (4) times.

Given the following data:

To determine the number of times the percentage of attacks on the dark-colored mouse is greater than the percentage of attacks on light-colored mouse.

Therefore, we would simply divide the percentage for the dark-colored mouse by the percentage for the light-colored mouse as follows:

[tex]Number \;of\;times = \frac{D}{L}[/tex]

Substituting the given parameters into the formula, we have;

[tex]Number \;of\;times = \frac{80}{20}[/tex]

Number of times = 4 times.

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[tex]\huge \bf༆ Answer ༄[/tex]

The Correct choice is ~ A

Isotopes are the elements with same Atomic Number but different masses ~

This question is providing the masses of carbon dioxide and oxygen gases at 10.0 atm as 66 g and 16 g respectively, and is asking for the partial pressure of the former which turns out to be 7.50 atm after doing the math.

Thus, we can start solving this problem with the Dalton's law approach, in order to make a relationship for the total pressure, partial pressure and mole fraction, which means we must first determine the mole fraction of carbon dioxide gas in the mixture as shown below:

[tex]x_{CO_2}=\frac{n_{CO_2}}{n_{CO_2}+n_{O_2}}[/tex]

Next, we calculate the moles of both gases by dividing the grams over the molar masses:

[tex]n_{CO_2}=\frac{66g}{44.01g/mol} =1.50mol\\\\n_{O_2}=\frac{16g}{32g/mol} =0.5mol[/tex]

Then, the mole fraction of carbon dioxide as the required one by plugging in the previously calculated moles:

[tex]x_{CO_2}=\frac{1.5}{1.5+0.5}=0.75[/tex]

Finally, we use the definition of the Dalton's law to calculate the partial pressure of carbon dioxide gas in the binary mixture:

[tex]P_{CO_2}=x_{CO_2}P\\\\P_{CO_2}=0.75*10.0atm\\\\P_{CO_2}=7.50 atm[/tex]

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Hydrogen  bonding interaction occurs between  the oxygen atom of water and  the hydrogen atom of allyl alcohol that is covalently bonded to the oxygen atom.

We must recall that allyl alcohol is a molecular substance. Molecular substances do not dissociate into ions in water. As such particles of allyl alcohol remain intact when dissolved in water.

Hydrogen bonding occurs when hydrogen is bonded to an electronegative atom such as oxygen. In allyl alcohol, hydrogen  bonding interaction occurs between  the hydrogen atom of water and the oxygen atom of allyl alcohol.

Also,  hydrogen  bonding interaction occurs between  the oxygen atom of water and  the hydrogen atom of allyl alcohol that is covalently bonded to the oxygen atom.

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Answer:

saturated solution because it can only dissolve upto fixed temperature

Answer:

Saturated

Explanation:

Explanation from online:

"When the solution equilibrium point is reached and no more solute will dissolve, the solution is said to be saturated. A saturated solution is a solution that contains the maximum amount of solute that is capable of being dissolved."

Stay Safe, and I hope this helps!!!!

Answer:

The answer is C.  Because particles can never stop moving

Explanation:

"All matter has thermal energy, even matter that feels cold. That's because the particles of all matter are in constant motion and have kinetic energy."

Answer:

B

Explanation:

because the electrons are moving fast

Answer:

Genes mainly, however the environment as well

Explanation:

Answer:

A I believe is your best choice.

Explanation:

Given that the volume and mass of a substance are not defining properties, it is entirely possible for two samples with different volumes and mass to be the same substance.

Therefore, since the volume and mass of a substance are not defining properties of a substance, we can confirm that it is entirely possible for two samples with different volumes and mass to be the same substance.

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Answer:

2.409*10^24

Explanation:

If I am not mistaken you are supposed to do 4*6.022*10^23. This will allow for it to be converted.

I hope this helped