Hello please I need help

Answer:

Alkali metals

Explanation:

Transition metals are known to have incompletely filled d- orbitals. For this reason, they are commonly referred to as the d- block. Cu4+  is a d7 ion.

An ion is formed when electrons are lost from or gained in a neutral atom.

An ion is a positively or negatively charged chemical specie. Chemical species form ions by loss or gain of electrons.

An atom is neutral if it has equal number of protons and electrons. When an atom has lost electrons, it forms a positive ion.

Copper has electronic configuration; 1s2 2s2 2p6 3s2 3p6 4s2 3d9. When four electrons are lost, its electronic configuration now becomes;

1s2 2s2 2p6 3s2 3p6 3d7.

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Explanation:

The trick here is to realize the every sample of sodium bromide, regardless of its mass, will contain

22.34

%

sodium by mass.

This is true because sodium and bromide always combine in definite proportions, i.e. stable ratios by mass, to form sodium bromide.

Now, a

22.34

%

percent concentration by mass means that every

100 g

of sodium bromide will contain

22.34 g

of sodium and

100 g

−

22.34 g

=

77.66 g Br

Therefore, you can say that the mass ratio that exists between sodium and bromine in any sample of sodium bromide will be

22.34 g Na

77.66 g Br

=

22.34

77.66

You can thus use this definite proportion to say that a

5.69 g

sample of sodium bromide will contain

5.69

g NaBr

⋅

22.34 g Na

100

g NaBr

=

1.271 g Na

=

¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯

∣

∣

a

a

1.27 g Na

a

a

∣

∣

−−−−−−−−−−−−−

The answer is rounded to three sig figs.

You can use the known definite proportion to find the mass of bromide present in the sample

1.271

g NaBr

⋅

77.66 g Br

22.34

g NaBr

=

4.42 g Br

This checks out because

mass of NaBr sample



5.69 g

−

mass of Na



1.27 g

=

mass of Br



4.42 g

The answers to your questions are ;

a) The mass percentage of Na in the sample will be higher in the sample

b) The mass percentage of Na in the sample will be be lower in the sample

Given that:

Mass percentage of sodium contained in sodium Bromide = 22.34%

a) Determine if the mass percentage of Na will be higher or lower when sodium Bromide is contaminated with sodium chloride  

mass percentage of Na in sodium bromide

= ( mass of Na / mass of NaBr )*100

The mass of sodium in NaBr and NaCl is the same while the mass of Br is not same ( greater than ) as the mass of Cl.  hence when NaBr is contaminated with NaCl the total mass of  in percentage NaBr will decrease. and This decrease in mass of NaBr will lead to a decrease/lower mass percentage of Na in the sample

b) When NaBr is contaminated with NaI

The mass of Na is the same in NaBr and NaI while the mass of I is not the same ( greater than ) as the mass of Br, therefore the total mass will increase and the increase in the Total mass in percentage will lead to an increase/higher value of Na in the given sample.

hence the mass percentage of Na will decrease when NaBr is contaminated with NaCl while the mass percentage of Na will increase when NaBr is contaminated with NaI

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Answer:

Electronic configuration of an element gives the information of valence electrons and number of shell present in the element.

Explanation:

Electronic configuration of an element gives the information of valence electrons and number of shell present in the element. We get the information of group number after knowing valence electrons.  

The number of shells present in an element is equal to the period number. Thus, by knowing electronic configuration we know the group number and period number of an element, and the position of an element in the periodic table.

An element's electronic configuration, which identifies both its period and group, gives important details regarding its place within the periodic table.

The major energy level (shell) where the outermost electrons are found determines the period. In the electrical arrangement, the period number corresponds to the greatest energy level. The number of valence electrons, which are the electrons at the highest energy level, which are present in an element determines its group or family. Because they have the same valence electron configurations, elements in the same group exhibit comparable chemical characteristics. In conclusion, the electronic configuration helps us comprehend an element's chemical behavior and interactions with other elements by revealing an element's period based on energy levels and its group based on valence electrons.

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Answer:

polar bonds- H2O, CO2, CH3CL,

The molecules that have polar bonds are CH₃Cl, and H₂O.

A polar bond is a type of covalent bond where the electron is unequally distributed.

This unequal distribution is due to the electronegativity difference of the attached atoms in the molecule.

A lewis structure of the molecule is studied to determine whether the compounds are polar and non-polar.

The molecule CCl₄: has one carbon atom at the center and the chlorine surrounds the carbon from all four sides, so even if there is a difference in the electronegativity the net dipole movement gets balanced from all four sides, so it is not a polar bond.

The molecule CH₃Cl

Similar to the CCl₄, hydrogen, and chlorine is surrounding the carbon, the three sides are hydrogen and one side is chlorine, so there is a net dipole movement and so it is a polar bond.

The molecule H₂O: The dipole movement of Hydrogen and oxygen are both in opposite directions and of different magnitude hence it will have a net dipole movement and so it is polar.

The molecule CO₂ and O₂ have net dipole movements as zero so are not polar compounds.

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Answer:

the relationship between the relative quantities of substances taking part in a reaction or forming a compound, typically a ratio of whole integers.

Explanation:

G o o g l e

Explanation:

Stoichiometry is the calculation of reactants and products in chemical reactions in chemistry.

Answer:

Only one of these methods separates compontents based on size.

The answer is filiration and chromatography.

Explanation:

Answer:

1 mol of cl2 contains 71 g

3 mol of cl2 will contain÷

3×71=213 g

Explanation:

There ;3

Answer:

213 g

Explanation:

multiply 3 moles by relative atomic mass of chlorine which is 35.45×2 because its two chlorines and your answer will be 213g

Answer:

Your answer is 5 x 10⁵

I hope it's helps you

Answer:

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Answer:

the answer is mostly option a)XCl

Explanation:

We have that the bone file from our research below

The is a very important tool in unlocking frozen joints by using its

Pull stroke

Serrated edges etc

And its also used in the field of dentistry.

Before we pick an instrument to focus on we first have to under stand what a frozen joints is

Frozen Joint,

Frozen Joint, which is also refereed to as adhesive capsulitis, is a situation whereby ones joints are stiff and they experience pain in the joint.

We focus on the

Bone file( principle)

It is made of a pull stroke which is designed to aid the removal of bones,they are also designed with serrated edges which are used in many different ways one of which is to smooth bones out in order to disinfect a given area

Bone file

This can also be used in the field of dentistry.

it puts into use it variant functions to make the work of a dentist easy

In conclusion

The Bone file is a very important tool in unlocking frozen joints by using its

Pull stroke

Serrated edges etc

And its also used in the field of dentistry.

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Answer:

C. kilograms, seconds, moles, and Kelvin

Answer:

Gas

Explanation:

I believe that it is usually a gas on Earth.

Answer:

H2SO4 AND NH3

Explanation:

I hope it will help you

Answer:

Explanation:

H2SO4 AND NH3

Answer:

Dehydrogenation is the process by which hydrogen is removed from an organic compound to form a new chemical (e.g., to convert saturated into unsaturated compounds).

Answer:

A. Complete one revolution around the sun

And do follow if you appreciate it

Answer:

Copper (Cu), chemical element, a reddish, extremely ductile metal of Group 11 (Ib) of the periodic table that is an unusually good conductor of electricity and heat. Copper is found in the free metallic state in nature.

Explanation:

hope this helps:)

Answer:

55/350

Explanation:

because the answer is in the middle of 50and 400

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Answer:

The correct answer is Science is objective, whereas pseudoscience is subjective. Pseudoscience includes beliefs, theories, or practices that have been or are considered scientific, but have no basis in scientific fact. This could mean they were disproved scientifically, can't be tested or lack evidence to support them.

Explanation:

hope its help

thank you

Answer:

The water falls to the earth as precipitation, such as rain, hail, sleet, and snow. When precipitation reaches the earth's surface, some of it will flow along the surface of the land and enter surface water like lakes, streams, and rivers, as runoff. The rest of it soaks or percolates into the soil, called

Answer:

-COOH

-CHO

-CO

-NH2

-X(-Cl, -Br, -I)

-RCOOR(R= Alkyl group)

-C6H5

The percentage abundance of  6Y is 0.102.

An Isotope refers to two or more atoms that has the same atomic number but different mass  numbers.

We have been informed from the question that the atomic mass of the element is 6.9412 amu.

Let the abundance of isotope 6Y be x

Let the abundance of isotope 7Y  be 1-x

Hence;

6.9412 = 6.015123x + 7.016005(1 - x)

6.9412 = 6.015123x + 7.016005 - 7.016005x

6.9412 - 7.016005 = 6.015123x - 7.016005x

-0.102 = -1x

x = -0.102/-1

x = 0.102

Hence the percentage abundance of isotope 6Y is 0.102.

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The percentage abundance of 6Y is 7.47%

Isotopy is the phenomenon whereby two or element have the same atomic number but different mass number due to the difference in their neutron number.

We'll begin the solving as follow:

Let A represent isotope 6Y

Let B represent isotope 7Y

From the question given above, the following data were obtained:

Mass of A = 6.015123 amu

Mass of B = 7.016005 amu

Abundance of B (B₀) = (100 – A₀%

Relative Atomic mass of Y = 6.9412 amu

The abundance of 6Y can be obtained as follow:

[tex]RAM = \frac{MassA * A_{0} }{100} + \frac{MassB * B_{0} }{100}\\\\6.9412 = \frac{6.015123 * A_{0}}{100} + \frac{7.016005 (100 - A_{0})}{100}\\\\6.9412 = 0.06015123 A_{0} + \frac{701.6005 - 7.016005A_{0}}{100}\\\\6.9412 = 0.06015123 A_{0} + 7.016005 - 0.07016005A_{0}[/tex]

Collect like terms

[tex]6.9412 - 7.016005 = 0.06015123A_{0} - 0.07016005A_{0}\\-0.074805 = -0.01000882A_{0}[/tex]

Divide both side by –0.0100882

[tex]A_{0} = \frac{-0.074805}{-0.01000882}\\\\[/tex]

Therefore, the abundance of 6Y is 7.47%

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Answer:  80 grams

Explanation:  

2KMnO4 -> K2MnO4+MnO2+O2​

2 moles of KMnO4 would produce 1 mole of MnO2, so 1 mole of KMnO4 would produce 0.5 moles of MnO4.  The molar mass of MnO4 is 160 g/mole.  1/2 mole of KMnO4 would therefore be (160 g/mole)*(0.5 moles) = 80 grams.