Copper produces a green flame test. When is the green light emitted?​

this will have ur answer

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   .   pb  .

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Answer:

7

Explanation:

Atomic number of X = 3

Atomic mass of X = 6.94 amu

1st isotope atomic mass = 6 amu

2nd isotope atomic mass = 7 amu

Which is more abundant isotope = ?

Explanation:

we know there are two naturally occurring isotopes of given element X, X-6  and X-7.

First of all we will set the fraction for both isotopes

x for the isotopes having mass 6

1-x for isotopes having mass 7

The average atomic mass of X = 6.94 amu

we will use the following equation,

6x + 7 (1-x) = 6.94

6x + 7 - 7x = 6.94

6x- 7x = 6.94 - 7

-1x = -0.06

x= -0.06/-1

x= 0.06

0.06 × 100 = 6%

6% is abundance of X-6 because we solve the fraction x.

now we will calculate the abundance of X-7.

(1-x)

1-0.06 =0.94

0.94 × 100= 94%

94% for X-7.

ans is A liquid........

Answer:

A.Liquid has no definite shape but does have a definite volume.

Explanation:

Hope it helps

Answer:

energy can neither be created nor be destroyed but it can only change  from one form to another or transfer from one to another object this is the simplest way of understanding the law of conservation of energy. In simple line its the transfer of energy only.

so now the potential energy is the energy that is in stored form while kinetic energy is that energy which an object contain due to any particular motion.

like a ball is thrown in air so the energy through which it goes upward is kinetic energy and for downward movement of ball it need another energy which is potential energy(in the stored form) and by using this energy it goes downward.

Answer:

3

Explanation:

Primary waves are radiated along a single direction, but secondary waves are radiated along all directions. That is why the P waves can take place in almost all mediums such as solid, liquid and air, unlike the S waves that are transverse and only travel through solid mediums

Answer:

Newton's second law of motion is F = ma, or force is equal to mass times acceleration. Learn how to use the formula to calculate acceleration

Explanation:

Answer:

Newton's laws can be experimentally verified because Newton's second law of motion is F = ma, or force is equal to mass times acceleration. Learn how to use the formula to calculate the acceleration. And so, using the equations and formulas we can use them and verify the laws.

Explanation:

good luck yalls ;P

Answer:

provide rewards to use solar power

Explanation:

Using solar power we can avoid bad energy like Coal, oil, natural gas, uranium and water from a dam.

All these kinds of energy producing air pollution, water pollution, or greenhouse gases.

But solar power has some toxic materials, also, using a lot of water to keep and clean solar power. In addition, if we create a solar power near a river or lake may cause damage.

We must think in these factors before to do a solar power.

Answer:

The scientist have developed to classify organisms because the living things with similarities can put into groups, which can further make easy to understand the relationship between them.

Explanation:

The scientist have classified organisms in different groups which can make their study easier. In this manner the organisms with same character will be in same group and their relationship and behavior with themselves as well as with others can be studied easily. It will make things less confusing. In this way the inheritance and genetic behavior can also be studied easily. This classification are based on various other categories like structure, function and also relationship with others.

Answer:

'classification allows for better identification of new organisms.'

Explanation:

Answer:

I'm pretty sure that the answer is D.

Answer:

464.1 J absorbed.

Explanation:

Given data:

Specific heat of zinc =  0.39 J/g°C

Mass of zinc = 34 g

Temperature changes = 22°C to 57°C

Energy absorbed or released = ?

Solution:

Formula:

Q = m.c. ΔT

Q = amount of heat absorbed or released

m = mass of given substance

c = specific heat capacity of substance

ΔT = change in temperature

ΔT = 57°C -  22°C

ΔT = 35°C

Q = m.c. ΔT

Q = 34 g. 0.39 J/g°C. 35°C

Q = 464.1 J

Answer:

Positive effect -  allow the search and development of environmental friendly sources, to decrease the risk of polluents in the ozone (in the world).

Negative effect - environmental imbalances like: toxic gas leaks, river and soil contamination, etc.

Explanation:

   Ozone (O3) is one of the gases that make up the atmosphere and about 90% of its molecules are concentrated between 20 and 35 km altitude, called the Ozone Layer. Its importance is that it is the only gas that filters out type B ultraviolet radiation (UV-B), which is harmful to living beings.  

  Ozone has different functions in the atmosphere depending on its altitude. In the stratosphere, ozone is created when solar ultraviolet radiation interacts with the oxygen molecule, breaking it into two oxygen atoms (O). The released oxygen atom attaches itself to an oxygen molecule (O2), thus forming ozone (O3). In the stratospheric region, 90% of type B ultraviolet radiation is absorbed by ozone.  At ground level in the troposphere, ozone loses its protective function and becomes a polluting gas, responsible for increasing surface temperature, together with carbon monoxide (CO), carbon dioxide (CO2), methane (CH4) and nitrous oxide.

  Several chemicals are destroying ozone. By reacting with it, the nitric and nitrous oxides expelled from vehicles and the CO2 produced by burning fossil fuels such as coal and oil are destroying the protective layer of the planet, opening holes in it.

  To reduce gas emissions, chemical professionals have been studying in depth the substitution of fossil energy, which generates a lot of pollution, by the so-called renewable energy. Other example can be the electric car, which is environmentally friendly because it does not emit polluting gases, is already a reality, sold in many countries. So, this a positive effect of chemistry nowadays, which it can allow the search for environmental friendly sources, to decrease the risk of polluents.

     But associated with progress, we have a multitude of environmental imbalances. Toxic gas leaks, river and soil contamination and poisoning by ingestion of contaminated food are problems shown daily - these could be some negative effects of chemistry nowadays.

Answer:

The benefits of CFCs include their use as coolants.

CFCs can be used as foaming agents and fire extinguishers.

CFCs, when released into the atmosphere, destroy ozone in the stratosphere.

CFCs destroy ozone in the stratosphere, which is the chemical layer that shields living things from too much ultraviolet radiation from the sun.

Answer:

19.12 moles of NO will produced.

Explanation:

Given data:

Mass of ammonia = 325 g

Moles of NO produced = ?

Solution:

Chemical equation:

4NH₃ + 5O₂ → 4NO + 6H₂O

Number of moles of Ammonia:

Number of moles = mass/ molar mass

Number of moles = 325 g/ 17 g/mol

Number of moles = 19.12 mol

Now we will compare the moles of ammonia and NO.

                   NH₃              :                NO

                      4                :                 4

                     19.12           :              19.12

Thus 19.12 moles of NO will produced.

Answer:

2Ag₂O  →  4Ag + O₂

Explanation:

Chemical equation:

Ag₂O  →  Ag + O₂

Balanced chemical equation:

2Ag₂O  →  4Ag + O₂

The given reaction is the decomposition of silver oxide. The silver oxide is decomposed into its constituent element silver and oxygen.

Decomposition reaction:

It is the reaction in which one reactant is break down into two or more product.

AB → A + B

This reaction also followed the law of conservation of mass because there are equal number of atoms of all elements on both side of equation.

Law of conservation of mass:

According to the law of conservation mass, mass can neither be created nor destroyed in a chemical equation.

This law was given by french chemist  Antoine Lavoisier in 1789. According to this law mass of reactant and mass of product must be equal, because masses are not created or destroyed in a chemical reaction.

Answer:

A: 238 g

B: 224 g

Explanation:

Data given:

A.

number of moles of H₂O₂ = 7.00 mole

mass of H₂O₂ = ?

B.

number of moles of NaOH = 5.60 mole

mass of NaOH = ?

Solution:

Part A:

Formula will be used

               no. of moles = mass in grams / molar mass

As we have to calculate mass of substance

So, rearrange the above equation

             mass in grams =  no. of moles x molar mass . . . . . . (1)

Molar Mass of H₂O₂ = 2(1) + 2(16)

Molar Mass of H₂O₂ = 2 + 32

Molar Mass of H₂O₂ = 34 g/mol

Put values in equation 1

                 mass in grams = 7.00 mol x 34 g/mol

                 mass in grams =  238 g

mass of H₂O₂ = 238 g

_______________________

Part B:

Formula will be used

               no. of moles = mass in grams / molar mass

As we have to calculate mass of substance

So, rearrange the above equation

             mass in grams =  no. of moles x molar mass . . . . . . (1)

Molar Mass of NaOH = 23 + 16 + 1

Molar Mass of NaOH  = 40 g/mol

Put values in equation 1

                 mass in grams = 5.60 mol x 40 g/mol

                 mass in grams =  224 g

mass of NaOH = 224 g

Answer:

O3+, O3, O3-

Explanation:

O3- has the highest bond angle because it has the highest electro negative value. Increase in electronegativity leads to increase in bond angles so as to minimize interelectronic repulsion between the electrons. Decrease in electronegativity leads to decrease in bond angle because the repulsion is minimized.

In general, the more electronegative an ion is, the larger the bond angle. The more electropositive an ion is, the smaller the bond angle. Hence cations are smaller than anions.

The bond angles of O3+, O3, and O3- can be ordered as O3- < O3 < O3+ from smallest to largest based on electron geometry and electron-electron repulsion.

When ordering the bond angles of O3+, O3, and O3- from smallest to largest, we must consider the electron geometry of each molecule/ion. In general, bond angles tend to decrease as the number of non-bonding electron pairs increases, due to the increased electron-electron repulsion.

In the case of O3+, it has fewer non-bonding electron pairs than neutral O3, leading to greater bond angles. O3, or ozone, has a bent molecular geometry, with a bond angle of roughly 117 degrees. O3-, or the ozone ion, has more non-bonding electrons, which will reduce the bond angle.

So, the bond angles would most likely be ordered as follows: O3- < O3 < O3+.

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Answer:

Halogens have 7 valence electrons.

Explanation:

They are the most active non-metals including fluorine, chlorine, bromine, iodine, and astatine

Answer:

Based on whether an element is a metal or non-metal, or their charge if given.

Explanation:

Cations are positively charged ions. Elements that are metals become positively charged.

Anions are negatively charged ions. Elements that are non-metals become negatively charged.

To identify the cation and anion in an ionic compound, name the cation first and the anion second without including the word 'ion'. If the cation can have multiple charges, include either the oxidation number according to the Stock system or use -ous/-ic suffixes in the classical system. The formula must reflect a balance of total positive and negative charges to ensure electrical neutrality.

To identify the cation and anion in an ionic compound, you follow specific nomenclature rules. The name of the ionic compound is written with the cation name first, followed by the anion name, without using the word ion for either. For example, to name Ba(NO₃)₂, you would call it barium nitrate, naming the metal barium as the cation followed by the anion nitrate.

When a cation has more than one possible charge, the compound is named either using the Stock system, which includes the cation's oxidation number, or by using the classical system, which includes the Latin-based name of the cation with the suffix -ous or -ic. For instance, FeCl₃ is named iron(III) chloride in the Stock system or ferric chloride in the classical system because iron can have multiple oxidation states.

To determine the correct number of ions for the formula, the overall charge of the compound must be neutral. This means the total positive charge of the cations must balance the total negative charge of the anions. Thus, writing the chemical formula involves deducing the correct ratio of ions so that their charges cancel each other out.

Answer:

gas

Explanation:

The gas molecules are far apart and as such, when heated they gain more kinetic energy thereby colliding with one another and with the wall of the container thereby exerting pressure and also they can be compressed by reducing the distance between between the molecules.

Matter is anything that is made up of atoms. Matter can be solid, liquid or gas.  Out of solid, liquid and gas, gas is the matter that expand on heating and compressed on cooling.

Matter is a substance that has some mass and can occupy some volume. The matter is mainly used in science. Anything around us that can be physically seen and touched are matter.

The intermolecular forces of attraction between the particles is highest in solid and lowest in gas. So, gas can be easily expand by increasing temperature. As the temperature increases the randomness between the particles also increases and hence particles move apart and expand. On decreasing pressure or temperature the randomness of particles decreases and hence particles comes closer and get compressed.

Thus out of solid, liquid and gas, gas is the matter that expand on heating and compressed on cooling

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Answer:

7628 y

Explanation:

Carbon-14 is radioactive and it follows the first-order kinetics for a radioactive decay. The first-order kinetics may be described by the following integrated rate law:

[tex]ln(\frac{[A]_t}{[A]_o})=-kt[/tex]

Here:

[tex][A]_t[/tex] is the mass, moles, molarity or percentage of the material left at some time of interest t;

[tex][A]_o[/tex] is the mass, moles, molarity or percentage of the material initially, we know that initially we expect to have 100 % of carbon-14 before it starts to decay;

[tex]k = \frac{ln(2)}{T_{\frac{1}{2}}}[/tex] is the rate constant;

[tex]t[/tex] is time.

The equation becomes:

[tex]ln(\frac{[A]_t}{[A]_o})=-\frac{ln(2)}{T_{\frac{1}{2}}}t[/tex]

Given:

[tex]\frac{[A]_t}{[A]_o} = \frac{40.0 %}{100.0 %}[/tex]

[tex]T_{\frac{1}{2}} = 5770 y[/tex]

Solve for time:

[tex]t = -\frac{ln(\frac{[A]_t}{[A]_o})\cdot T_{\frac{1}{2}}}{ln(2)}[/tex]

In this case:

[tex]t = -\frac{ln(\frac{40.0\%}{100.0\%})\cdot 5770 y}{ln(2)}[/tex]

[tex]t = 7628 y[/tex]

Answer:

a. Be and Mg

Explanation:

Be (beryllium) and Mg (magnesium) are both found in the alkaline earth metals family (group 2) on the periodic table. Elements in the same family or group have similar properties,

Ca and Br are in groups 2 and 17

Cl and Ar are in groups 17 and 18

Na and P are in groups 1 and 15

D

Molecular motion increases as temperature increases and therefore increasing the molecular motion increases collision frequency.

Explanation:

When a substance is heated, its molecules gain increased kinetic energy even as the substance increases in temperatures. With higher kinetic energy, this means the molecules are moving more rapidly and hence collision between the molecules will be more frequent and of higher energy. It is these high energy collisions that cause the molecules to move further away from each other with increased temperatures (why substances expand).  

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Answer: Your answer would be D

Explanation: This is because whenever the collision increases the molecular motion increases with it.

Answer:

I think the answer is 13H

Explanation:

The best known example of a naturally-occurring radioisotope is uranium. All but 0.7 per cent of naturally-occurring uranium is uranium-238; the rest is the less stable, or more radioactive, uranium-235, which has three fewer neutrons in its nucleus.

Answer: Adolf Hitler was a German politician and he made the Nazi Party. He rose to power when he was the chancellor. He was also a dictator and he caused World War 2 when he invaded Poland September 1, 1939.

Answer: Adolf Hitler created the Nazi Party. He was a dictator and he rose to power when he was the chancellor in 1933 and then Fuhrer in 1934. He was the cause of World War 2 when he had invaded Poland.

*Fuhrer is a German term which means "The Leader".

8) 21.504 liters of gas

9) 122.5 g

10) 6.022*10^23

Explanation:

8)

1 mole= 22.4 liters

to calculate the volume of gas of 0.960 moles of CH4

22.4*0.960/1

= 21.504 liters of gas  

9)

2.0 mole*18.02 g/ 1 mole

=122.5 g

10)

2.0 l * 1 mole/22.4 l

6.022*10^23

Oxygen is the most active non-metallic element in Group 16 of the periodic table, also known as the oxygen family. This is primarily due to its small atomic size relative to other elements in the group.

The most active non-metallic element in Group 16 of the periodic table is oxygen. Group 16 elements are also known as the oxygen family. These elements become less active as you move down the group due to an increase in atomic size, which contributes to a decrease in electronegativity. Among the members of this group, oxygen has the smallest atomic size, making it the most active nonmetal in this group. Examples of other elements in this group are sulfur, selenium, tellurium, and polonium, but oxygen is significantly more reactive.

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Answer:

A.

Explanation:

A base is a substance that produces hydroxide ions in an aqueous solution.

A base is defined as a compound that produces hydroxide ions in solution (option A).

A base in chemistry is a water-soluble compound having bitter taste, that turn red litmus blue, and react with acids to form salts.

Asides the above properties of a base, a base is capable of producing hydroxide ions (OH-) when dissociated in an aqueous solution.

Examples of bases that would dissociate in water to produce hydroxide ions are as follows:

Therefore, option A is correct.

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Answer:

Grass, deer, wolf, fungi.

Explanation:

The tropical level of an organism is defined as the position of organism occupied in the food chain. The food chain is starts from tropical level one which is primary producers (such as plants), then move to herbivores (such as deer) in level two, carnivores, (such as wolf) at level three, apex predators in level four (such as lions), and it ends in decomposers such as fungi.

Fungi play important role in ecosystem to help in breakdown of dead organic matter and return nutrients to the soil. Without fungi nutrients cannot cycle in an ecosystem, and causing the breakdown of entire food web.

Answer:

Minimizing repulsion by maximizing the bond angles

Explanation:

VSEPR is defined as 'valence shell electron pair repulsion' theory. The key principle is that repulsion of adjacent lone pairs of electrons or the electrons that are shared within a bond creates bond angles.

The bond angles are maximized in order to minimize the repulsion in the most stable geometrical shape of the molecule.

That said, in VSEPR theory we tend to achieve the greatest possible angles between the bonds and lone pair electrons in order to obtain the lowest repulsion between them.