Which is the correct chemical symbol for this atom of helium?

Answer:

3. A chemical reaction has occured

A student mixes two liquids together and notices that a white solid has formed at the bottom of the container which means precipitate has formed.

What is precipitation reaction ?

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Answer:

3 - True

4 - True

5 - False

6 - False

Answer:

See explanation

Explanation:

The principle of conservation of energy states that energy can neither be created nor destroyed but can be converted from one form to another. Hence, chemical energy in a battery can be converted to electrical energy.

Usually, the conversion of energy from one form to another is not 100% efficient according to the second law of thermodynamics. Some energy is wasted in the process, sometimes as heat.

Hence, in an ideal situation where no heat energy is produced; all the chemical energy is converted to electrical energy (100% energy conversion). There will be no energy loss if no heat is produced.

Answer:

4.938×10^24 molecules

Explanation:

a mole is 6.023×10^23

(8.2)×(6.023×10^23)=4.938×10^24

Answer:

the pH solution is 4.9.

[[tex]H^{+}[/tex](aq)] = [tex]10^{-pH}[/tex]

Explanation:

Answer:

pretty sure that's an old jolly rancher

Given :

A sample of unknown gas has a temperature of 378 K.

[tex]T_i = 378 \ K , \ T_f = 546 \ K[/tex]

When the temperature is increased to 546 K, the volume also increases to 1047 ml.

[tex]V_f - V_i = 1047 \ ml[/tex]

Solution :

We know, temperature is directly proportional to volume.

[tex]\dfrac{T_i}{T_f}=\dfrac{V_i}{V_f}\\\\\dfrac{T_i}{T_f} = \dfrac{V_i}{1047 + V_i}\\\\\dfrac{V_i}{1047+V_i}=\dfrac{378}{546}\\\\546V_i = 378V_i + 378\times 1047\\\\168V_i = 3,95,766\\\\V_i = 2,355.75\ ml[/tex]

Therefore, the original volume is 2.355.75 ml.

Answer:

2nd one

Explanation:

Fact!

Answer:

More energy then closer electrons.

Explanation:

As electrons move away from the nucleus, their energy increases.

Answer: Any force that causes an object to move in a circle is called centripetal force.

Answer:

I think it is D

Explanation:

Answer:

the answer is B

Explanation:

Answer:

chemical energy

Explanation:

This energy process is called exothermic when the reactants are at a higher energy level as compared to the products while it is an endothermic process if the reactant require energy to form products.

The covalent bonds that bring atoms together in the form of molecules store potential energy. This is commonly referred to as chemical energy.

When two different elements bond together to form compounds , the covalent bonds initial present are broken and new bonds are formed .

The energy level of the new formed compound will be lower than the individual atom as the difference in energy level of both the elements is released as heat.

This energy process is called exothermic when the reactants are at a higher energy level as compared to the products while it is an endothermic process if the reactant require energy to form products.

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Answer:

In order to balance the chemical equation, you need to make sure the number of atoms of each element on the reactant side is equal to the number of atoms of each element on the product side. In order make both sides equal, you will need to multiply the number of atoms in each element until both sides are equal

Explanation:

Answer:

what he said so you can give him brainliest

Explanation:

your answer is D. physical change, because a new substance is not formed.

The boiling process  is considered to be a physical change as no new substance is formed.

Physical changes are defined as changes which affect only the form of a substance but not it's chemical composition. They are used to separate mixtures in to chemical components but cannot be used to separate compounds to simpler compounds.

Physical changes are always reversible using physical means and involve a change in the physical properties.Examples of physical changes include melting,boiling , change in texture, size,color,volume and density.Magnetism, crystallization, formation of alloys are all reversible and hence physical changes.

They involve only rearrangement of atoms and are often characterized to be changes which are reversible.

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Answer:

The answer would probably be C. The clock can be seen and heard.

Answer:

17.25 degrees

Explanation:

....but I cannot tell you if that is   °C    or    °F    <===== that is left out of the question.

Answer:

Solution B is saturated and solution A is unsaturated

Explanation:

Saturated solution contains the maximum concentration of a solute dissolved in the solvent (usually water) and if extra solute is added to saturated solution, that solute will not dissolve.

Unsaturated solution means that more of a substance can be dissolved (in this example salt).

Answer:

Start off and multiply the volume value by 1000,

so that would mean

5000 x 1000

= 5,000,000 mL

Answer: Your friend is incorrect.

Explanation: If we have an object or something that isn’t moving, (let’s say a notebook on a desk). If there is change, and the notebook moves, there is acceleration. Force = Mass times acceleration, f = m*a. There has to be a force, first of all. If you touched the notebook and moved it, some of your energy is transferred and now the notebook has kinetic energy. If our system is you and the notebook, the total energy doesn’t change. the energy is transferred, but doesn’t change. Your friend is not correct. Please give brainliest hope this helped!

The option that is the structural units that make up ionic solids is option   D. Ions

Ionic solids are made up of ions, which are atoms or groups of atoms that have a positive or negative charge due to the gain or loss of electrons. In ionic solids, the positive ions (cations) are typically formed by metal atoms, while the negative ions (anions) are typically formed by nonmetal atoms. The ions in ionic solids are held together by electrostatic forces of attraction, called ionic bonds.

Therefore, These bonds are formed when the electrons from the outermost energy level of the metal atom are transferred to the outermost energy level of the nonmetal atom, creating a stable compound.

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According to stoichiometry as 162.955 g of phosphorous pentanitride has 92.919 g of phosphorous , thus 245 g of phosphorous pentanitride   will have 139.7 grams of phosphorous.

Stoichiometry is the determination of proportions of elements or compounds in a chemical reaction. The related relations are based on law of conservation of mass and law of combining weights and volumes.

Stoichiometry is used in quantitative analysis for measuring concentrations of substances present in the sample.It is important as it helps the chemical reactions to obey law of conservation of mass.

As  162.955 g of phosphorous pentanitride=92.919 g of phosphorous

∴ 245 g of phosphorous pentanitride   =245×92.919/162.955=139.702 g.

Thus, 139.702 g  of phosphorus can be recovered from 245.0 g triphosphorus pentanitride.

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Answer:

As you noticed, the percent-error formula needs you to use a value in the ... The actual absolute zero is 275C below my coldest recorded value. ... The only way your calculations makes sense is you're trying to calculate how ... Next, I'll interpret "I found that AZ is at -258°C" as "I calculated AZ to be 260 degrees below 2°C".

Explanation:

The experimental error will be 8.95%

The formula  used for calculating the percentage error is expressed as:

[tex]\% error=\frac{|exp. \ value - actual \ value|}{actual \ value} \times 100[/tex]

Given the following parameters

Actual value = −273.15 degrees Celcius

Let the experimental value be 300 degrees Celcius (since we are not given)

[tex]\% error=\frac{|300 - 273.15|}{300} \times 100\\\% error=\frac{|26.85|}{300} \times 100\\\% error=8.95\%[/tex]

Hence the experimental error will be 8.95%

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Answer:

The new volume of the gas is 42.28 mL.

Explanation:

Gay Lussac's law indicates that when there is a constant volume, as the temperature increases, the pressure of the gas increases. And when the temperature is decreased, the pressure of the gas decreases. This law can be expressed mathematically as follows:

[tex]\frac{P}{T}=k[/tex]

where k = Constant

Boyle's law says that "The volume occupied by a given gaseous mass at constant temperature is inversely proportional to pressure." This law is expressed mathematically as:

P * V = k

Finally, Charles's Law indicates that as the temperature increases, the volume of the gas increases and as the temperature decreases, the volume of the gas decreases. In summary, Charles's law is a law that says that when the amount of gas and pressure are kept constant, the quotient that exists between the volume and the temperature will always have the same value:

[tex]\frac{V}{T}=k[/tex]

Combined law equation is the combination of three gas laws called Boyle's, Charlie's and Gay-Lusac's law:

[tex]\frac{P*V}{T}=k[/tex]

Studying an initial state 1 and a final state 2, it is satisfied:

[tex]\frac{P1*V1}{T1}=\frac{P2*V2}{T2}[/tex]

In this case:

Replacing:

[tex]\frac{740 mmHg*36 mL}{306 K}=\frac{1750 mmHg*V2}{850 K}[/tex]

Solving:

[tex]V2=\frac{850 K}{1750 mmHg} *\frac{740 mmHg*36 mL}{306 K}[/tex]

V2= 42.28 mL

The new volume of the gas is 42.28 mL.

Answer:

answer is

c. Polar

hope this helps

Answer: i think it’s two recessive alleles

Explanation:

Answer:Two recessive alleles is correct

Explanation:

I TOOK THE TEST (k-12 student) TwT