Why are noble gases called "safe" gases?

Changes in shape and state are the two characteristics  which indicate a physical change.

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:

Im confused. Do you need help with something?

Explanation:

Answer:sheshhh sayless XD

Explanation:

Answer:

i think its C

Explanation:

Answer:

✖︎ Mixture←  is the right answer answer, so don't choose that....…

THE corrects answer would be MIXTURE

!!!!!!Brainliest??

EXPLANATION

✰1.  I take the quiz

✰2. The word already describe it self, mixture is a substance made by mixing other substances together.

✰a mixture is a material made up of two or more different substances which are physically combined. A mixture is the physical combination of two or more substances in which the identities are retained and are mixed in the form of solutions, suspensions and colloids.

Answer:

The answer will be listed below.

Explanation:

An acid is a substance that produces (H+) as the only positive ion when mixed with water. A base is a substance that produces (OH–) as the only negative ion when mixed with water.

Answer:

An acid increases the concentration, A base is a substance that releases hydroxide

Explanation: A base donates electrons and accepts protons, and acid is a substance that donates protons.

Answer:

What is the total number of joules of heat energy needed to 16) How many joules of heat ... raise the temperature of 10 grams of water from 20°Сto ... 2) · The temperature of 100 grams of water changes from 16°C/7How many kilojoules of ... temperature of 500. grams of water from 10.0°C to 30.0°C? ... m250 -Q=209051. | c= ...

Explanation:

I hope I help :))

Answer:

Explanation:

The density of a substance can be found by using the formula

[tex]density = \frac{mass}{volume} \\ [/tex]

volume = final volume of water - initial volume of water

volume = 75 - 50 = 25 mL

We have

[tex]density = \frac{5}{25} = \frac{1}{5} \\ [/tex]

We have the final answer as

Hope this helps you

Answer:

Is when there is an increase in the temperature of the liquid

Explanation:

Increase in temperature of the liquid is an indication that chemical change occur because chemical change occur through process of chemical reaction and it involve when two or more substances combine together to form new substances which is as a result of change in chemical composition. The crystals dissolved in water to form another new solution and it became warm and this indicate a chemical change, new substances are formed as a result of increase in temperature.

Answer:

4.5moles

Explanation:

Given parameters:

Mass of Na₃P = ?

Unknown:

Number of moles  = ?

Solution;

The number of moles in a given substance can be derived from the expression below;

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

Molar mass of  Na₃P   = 3(23) + 31 = 100g/mol

   Number of moles  = [tex]\frac{450}{100}[/tex]   = 4.5moles

Answer:

It would be better if you posted the question, thank you.

Explanation:

Answer:

The beginning

Explanation:

In a nuclear reaction, the  rate of decay is fastest at the beginning of the process.

There are two types of nuclear reactions which are nuclear fusion and nuclear fission .They involve the combination and disintegration of the element's nucleus respectively.

In nuclear fission, the nucleus of the atom is bombarded with electrons of low energy which splits the nucleus in to two parts .Large amount of energy is released in the process.It is used in nuclear power reactors as it produces large amount of energy.

In nuclear fusion,on the other hand, is a reaction which occurs when two or more atoms combine to form a heavy nucleus.Large amount of energy is released in the process which is greater than that of the energy which is released in nuclear fission process.

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Answer:

See explanation

Explanation:

Atomic size increases down the group due to the addition of more shells.

As more shells are added and repulsion of inner electrons become more significant, atomic size increases down the group. However, across the period, atomic size decreases due to increase in effective nuclear charge without any increase in the number of shells. This causes increased attraction between the nucleus and the outermost shell thereby decreasing the size of the atom.

Ionization energy decreases down the group because the outermost electron is more shielded by inner electrons making it easier for this outermost electron to be lost. Across the period, ionization energy increases due to increase in effective nuclear charge which makes it more difficult to remove the outermost electron due to increased nuclear attraction.

Answer:

2. Isotope, one of two or more species of atoms of a chemical element with the same atomic number and position in the periodic table and nearly identical chemical behavior but with different atomic masses and physical properties. Every chemical element has one or more isotopes.

3. Since the vast majority of an atom's mass is found its protons and neutrons, subtracting the number of protons (i.e. the atomic number) from the atomic mass will give you the calculated number of neutrons in the atom. In our example, this is: 14 (atomic mass) – 6 (number of protons) = 8 (number of neutrons).

Explanation: Try rewording the questions when looking it up.  Hope this helps

Answer:

9. 2(2n^2)

10. Electron Shell

11.-

12.-

13.-

14.-

Explanation:

i hope it helped

Mass of Mg=3 g

The mole is the number of particles contained in a substance

1 mol = 6.02.10²³

mol Mg in 7.43 x 10²² atoms :

[tex]\tt \dfrac{7.43\times 10^{22}}{6.02\times 10^{23}}=0.1234[/tex]

mass Mg

[tex]\tt mass=mol\times MW\\\\mass=0.1234\times 24.3=2.99\approx 3[/tex]

Answer:

An oxidising agent oxidises something else. Oxidation is loss of electrons (OIL RIG). That means that an oxidising agent takes electrons from that other substance.

Explanation:

NaoH+HcI→ NaCl +H2O

Na0H=23+16+l= 40 9m

Nacl=23 +35.5 =58.5 gm

mass of NaOH required=117x40/ 58.5 =80 gm

Molar mass of NaOH = 23+16+1 =40g/mol

Molar mass of NaCl = 23+35.5 =58.5g/mol

To produce 58.5g NaCl 40g NaOH is required

So, to produce 117g NaCl {(40/58.5)×117}g = 80g NaOH is required.

Hope, this helps.

Explanation:

The increase in mass is because the iron fillings have combined with a sulfide to produce iron sulfide and so the mass will increase.

In such a reaction like this, the mass of the reactants must be conserved. By so doing, the mass of reactants and products must be the same.

When two substances combine together, their masses added up to that of the individual masses. This helps to conserve the mass.

2.1 x 10⁵⁶ atoms

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

1 mol = 6.02.10²³

number of atoms :

[tex]\tt 3.49\times 10^{32}\times 6.02\times 10^{23}=2.1\times 10^{56}[/tex]

Answer: D 25 degrees

Explanation: The reason because is 25x4=100 and slightly tilted =1/4 of the earth which is 25

Answer:

See explanation

Explanation:

A gene mutation can be defined as a permanent change in the DNA sequence that composes a gene, resulting in the observation that the sequence differs from what is obtainable in most individuals that make up the  population. Mutations range from a change in a single DNA building block (change in the sequence of base pairs) to changes in a large segment of a chromosome that includes multiple genes.

Mutation in the color of the wings of the housefly can be passed on to the next generation. If this trait enhances survival of the butterflies, the orange winged butterflies will eventual become extinct and become entirely replaced by the white winged butterflies. This implies that gene pool has been completely modified.

If same kind of mutation of pigmentation of wings is observed in the butterfly then they will result in a white butterfly.

If a gene of the DNA get damaged or changes in such a way that it also results in the changing of genetic message carried by that gene and this process is known by the name of mutation.

In the given question by breeding orange butterfly with a white butterfly in the latest generation of animals, notices a mutation in the genes that calls for pigment in the wings. If the mutation of pigmentation of wings is passed to the next generations with the  same changes in the gene of DNA, then after some generation we would get white butterfly.

Hence, if the same changes observed in the mutation of pigmentation of wings then we get a white butterfly.

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Answer:

It is where the water lies underground

Answer:

In physics and chemistry, ionization energy or ionisation energy, is the minimum amount of energy required to remove the most loosely bound electron of an isolated neutral gaseous atom or molecule.

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Explanation:

Answer:

increase is the answer for both ig?

Answer:

let the number be x

so (x+6)/3 =5

x+6=15

x=9

Answer:

plants

Explanation:

Answer:

Covalent Bonds

General Formulas and Concepts:

Explanation:

We have 3 types of bonds: Polar Covalent, Nonpolar Covalent, and Ionic bonds.

Nonpolar Covalent bonds share the electrons equally between the compound.

Polar Covalent bonds do NOT share the electrons equally, but STILL SHARE the electrons; the electron tends to stay with the element with the stronger electron affinity and thus creates dipoles.

Ionic bonds DO NOT share electrons. The electrons are transferred to the respective elements.

Answer:

Explanation:

given,

velocity = 5m\s

mass = 50kg

kinetic energy = ?

therefore, we know that,

kinetic energy = 1\2 * mass * velocity^2

                        = 1\2 * 50* 5 ^ 2

                        = 1\2 * 50* 25

                         = 1\2 * 1250

                         = 625

therefore, kinetic energy is 625

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