boron has two naturally occurring isotopes .there are 10 b(20%)and 11b(80%).what is the average atomic mass of boron

Answers

Answer 1

Answer:

Explanation:

Average Atomic mass of any element =[ ∑ Abundance* mass of element] /100

                                                                = 10*20 +11*80 /100

                                                                = .........

Hope this helps you


Related Questions

What is chemical potential energy?

Answers

Answer:

It is the energy that is stored in bonds that hold particles together

Explanation:

How many electrons must calcium lose to satisfy the octet rule?
Gain 2 electrons
Lose 2 electrons
Lose 40 electrons
Lose 20 electrons
• Previous
Next >

Answers

Answer:

Lose 2 electrons

Explanation:

Express your views on how the law, the citizens and community can protect and support victims of human rights violations

Answers

Answer:

it all really depends on the superiors of the government. everyone's so corrupt with their views these days, and let personal opinions rules over what the people want. as a latina, i think we should keep fighting and protesting till we get what we really deserve.

Explanation:

Which of these pulls denser rocks towards Earth's center?
1.thermal energy
2.gravity
3.radiation

Answers

Answer:

Gravity pulls denser rocks down toward Earth's center. This causes less dense rocks and magma to move upward toward the surface.

Answer:

Gravity boo

Explanation:

Which list of elements contains a metal, a metalloid,a nonmetal, and a noble gas

Answers

It was C when I did it but probably b

Answer:

sodium, silicon, and argon

Explanation:

castle learning

Connie was making sodium chloride by adding an acid to an alkali. She followed the progress of the reaction with a pH sensor .What else could she have used to detect when the reaction was complete?

Answers

What Connie could have used to detect when the chemical reaction was complete is an: acid-base indicator.

A chemical reaction is a chemical process that involves the continuous rearrangement (transformation) of either the ionic, atomic or molecular structure of a chemical element through the breakdown and formation of chemical bonds, in order to produce a chemical compound.

When a strong acid such as Hydrogen chloride (HCl) react with a strong alkali such as Sodium hydroxide (NaOH), it gives rise to the formation of Sodium chloride (NaCl) and Water ([tex]H_2O[/tex]);

                       [tex]HCl + NaOH[/tex] ----> [tex]NaCl + H_2O[/tex]

The progress of the above chemical reaction can be followed by using a pH sensor and the final pH of a strong acid and strong base is seven (7), meaning it is neutral.

However, Connie could make use of an acid-base indicator to detect when the chemical reaction is complete.

An acid-base indicator can be defined as a chemical substance that changes color with respect to the pH (hydrogen ion concentration) of a solution or chemical reaction. Some examples of an acid-base indicator are:

Litmus paper.Methyl red.Red cabbage juice.Bromothymol blue.Methyl orange.Phenolphthalein.

In conclusion, an acid-base indicator is typically used for detecting when a chemical reaction between an acid and an alkali is complete.

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Answer:When a strong acid such as Hydrogen chloride (HCl) react with a strong alkali such as Sodium hydroxide (NaOH), it gives rise to the formation of Sodium chloride (NaCl) and Water ();

---->

Explanation:

Use the drop-down menus to complete the statements

Answers

Answer:

First one: group

Second one: period

Third one: number of valence electrons

Last one: increases

what is pyruvate converted to

Answers

Answer:

gold

Explanation:

a sample of a compound that contains only the elements C,H and N is completely burned in O2 to produce 44g of CO2, 45g of H2O, and some NO2. A possible empirical formula of the compound is A. CH2N B.CH5N C.C2H5N D.C3H3N2

Answers

Answer:

B. CH₅N

Explanation:

The combustion reaction of a compound CₐHₓNₙ with O₂ is:

CₐHₓNₙ + O₂ → a CO₂ + X/2 H₂O + n NO₂

Where 1 mole of CₐHₓNₙ with an excess of O₂ produce a moles of CO₂, X/2 moles of H₂O and n moles of NO₂

Thus, you need to convert the mass of CO₂ and H₂O to moles to find the C:H ratio and determine a possible empirical formula thus:

Moles CO₂ (Molar mass 44g/mol):

44g ₓ (1mol / 44g) = 1 mole CO₂ = 1 mole C

Mole of H₂O (Molar mass 18g/mol):

45g ₓ (1 mol / 18g) = 2.5 moles H₂O = 5 moles H

Thus, in the compound you have 5 moles of H per mole of C, and a possible empirical formula is:

B. CH₅N

The only structure that meet this C:H ratio

The most likely empirical formula for the one that exemplifies a specimen of the compound containing the element C, H, and N which are completely combusted in oxygen to generate 44g Co2, 45g of H2O, and a little NO2 would be:

B). CH₅N

 

The reaction of combustion taking place in the compound CₐHₓNₙ using [tex]O_{2}[/tex] (oxygen) would be:

[tex]C_{a} H_{x} N_{n} + O_{2}[/tex]  → [tex]aCO_{2} + X/2 H_{2}O + nNO_{2}[/tex]

In this reaction, 1 mole belonging to [tex]C_{a} H_{x} N_{a}[/tex] having additional [tex]O_{2}[/tex] (oxygen) leads to generating '[tex]a[/tex]' moles of [tex]CO_{2}[/tex] (Carbon dioxide), [tex]X/2[/tex] number of moles of [tex]H_{2}O[/tex](Hydrogen), and n amount of moles of Nitrogen([tex]N[/tex]).

Therefore, it will be required to transform the mass of [tex]CO_{2}[/tex] and [tex]H_{2}O[/tex]  in the form of moles to deduce the ratio C:H to look for the likely empirical formula.

 [tex]CO_{2}[/tex] Moles                                                       (∵ Molar mass [tex]= 44g/mol)[/tex]

= [tex]44g[/tex] × [tex](1mol/44g)[/tex]

[tex]= 1 mole[/tex] of  [tex]CO_{2}[/tex]

[tex]= 1 mole[/tex] of C

[tex]H_{2}O[/tex] Moles                                                   (∵ Molar mass =[tex]18g/mol)[/tex]

[tex]= 45g[/tex] ₓ [tex](1 mol / 18g)[/tex]                          

[tex]= 2.5 moles[/tex]  [tex]H_{2}O[/tex]

[tex]= 5[/tex] [tex]moles of H[/tex] because (H * 2)

∵ The C:H ratio is 1:5 implying that formula would include 5 H moles and 1 C mole. So, CH₅N is the correct option.

Thus, option B is the correct answer.

Learn more about 'Compound' here:

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metallic pan is provided with a wooden plastic handle give reason​

Answers

The metallic pan iis most likely going to be used on a stove.

The stove is heating something, and the conductive metallic pan will, well, conduct that heat throughout the entire body of the pan. Doing this will spread the heat to the handle, burning your hands.

Both wood and plastic are insulators, and they do not conduct heat or electricity. They will insulate your hands and protect them from the heat.

Which statement describes a process involved in the evolution of Earth’s early atmosphere?
A.
Cyanobacteria transformed carbon dioxide in the atmosphere into oxygen during photosynthesis.
B.
Heavier gases escaped through Earth’s atmosphere, leaving only lighter gases such as oxygen behind.
C.
Volcanic eruptions produced enough oxygen to create Earth’s atmosphere.
D.
The amount of oxygen in the atmosphere declined due to respiration, or breathing.A sea breeze is a wind that blows from the sea toward land. Which statement best explains how air pressure influences sea breezes?
A.
Wind always blows from the sea toward land, regardless of differences in air pressure.
B.
The air above the land has a lower pressure than the air above the sea.
C.
The air above the sea has a lower pressure than the air above the land.
D.
The sea and the land are at equivalent air pressures, so waves cause the wind to move toward the land.

Answers

Answer:

D

Explanation:

D. The sea and land are at the equivalent etc ..

Of the choices below, which one is not an ionic compound?
A) PCl5
B) MoCl6
C) RbCl
D) PbCl2
E) NaCl

Answers

Answer: [tex]PCl_5[/tex] is not an ionic compound.

Explanation:

An ionic compound is defined as the compound which is formed when electron gets transferred from one atom to another atom.  The cation is formed by loss of electrons by metals and anions are formed by gain of electrons by non metals.

Thus [tex]MoCl_6[/tex], [tex]RbCl[/tex], [tex]PbCl_2[/tex] and [tex]NaCl[/tex] are all ionic compounds.

Covalent compound is defined as the compound which is formed by the sharing of electrons between the atoms forming a compound. These are usually formed when two non-metals react.

Thus [tex]PCl_5[/tex] is a covalent compound as both Phosphorous and chlorine are non metals.

PCl₅ is not an ionic compound. Ionic or electrovalent compounds are formed

through the transfer of electrons in a chemical reaction. Metals and non-

metals mostly form ionic compounds.

Covalent bonding on the other involves the sharing of electrons between

two elements. Non-metals are mostly involved in this type of reaction.

PCl₅ possesses a covalent bond and not ionic as electrons are shared

between two non metals  which are phosphorus and chlorine.

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8. A 65.0 mL 0.513 mol/l solution of glucose (C6H1206) was mixed with 125.0 mL of
2.33 mol/l glucose solution. What is the molar concentration of the final solution?
Assume the volumes are additive. The molar mass of glucose is 180 g/mol (10
points)

Answers

Answer:

The molar concentration of the final solution is 1.71 [tex]\frac{moles}{liter}[/tex]

Explanation:

Molarity is a way of expressing the concentration of solutions and indicates the number of moles of solute dissolved per liter of solution.

The molarity of a solution is calculated by dividing the moles of the solute by the volume of the solution.:

[tex]Molarity (M)=\frac{number of moles of solute}{volume}[/tex]

Molarity is expressed in units ([tex]\frac{moles}{liter}[/tex]).

Then, the number of moles of solute can be calculated as:

number of moles of solute= molarity* volume

So, in this case, the final concentration can be calculated as:

[tex]Final molarity (M)=\frac{Total number of moles of solute}{Total volume}[/tex]

where, being 65 mL=0.065 L, 125 mL=0.125 L and 190 mL=0.190 L (because 1000 mL= 1 L):

Total number of moles of solute= 0.065 L*0.513 [tex]\frac{moles}{liter}[/tex] + 0.125 L*2.33 [tex]\frac{moles}{liter}[/tex]= 0.033345 moles + 0.29125 moles= 0.324595 molesTotal volume=  65 mL + 125 mL= 190 mL= 0.190 L

Replacing:

[tex]Final molarity (M)=\frac{0.324595 moles}{0.190 L}[/tex]

Final molarity ≅ 1.71 [tex]\frac{moles}{liter}[/tex]

The molar concentration of the final solution is 1.71 [tex]\frac{moles}{liter}[/tex]

What is the molar mass of Al2(SO4)3?

Answers

Answer:

342.14g/mol.

Explanation:

The molar mass of Al2 (SO4)3 is 342.15g/mole.

Reasons that one aluminum atom=26.98. Therefore two aluminum atoms:=2(26.98 g/mole) =53.96 g/mole.

Mass of SO4=96.06g/mol.

Therefore molar mass of Al2(SO4)3= 53.96+(96.06)×3=342.14g/mol

Answer:

342.17 g/mol

Explanation:

Al= 26.98    

S= 32.07

O= 16.00

To calculate that you would have

2(26.98) since there are two Als

and then you have to distribute the 3 to the S and O so...

3S and 12O

which is

3(32.07) + 12(16.00)

which means you add

2(26.98) + 3(32.07) + 12(16.00)

=53.96 + 96.21 + 192

=342.17

there you Go! the final answer is 342.17 g/mol.

A 50.0 mL sample of 6.0 M HCl was diluted to a final volume of 250.0 mL What was the new molarity?

Answers

Answer:

1.2M

Explanation:

Initial Volume 0.05L

Final Volume 0.250L

HCl Molar mass: 36.46 g/mol

M = 6M HCl

Molarity = mol solute /  L of solution

Inital M = Molarity = 6

mol solute = X = unknown

L of Solution = 0.05L

6 = X / 0.05

X = 0.3

X = 0.3/0.25

X = 1.2 M

​  

S
Perform the following operation
and express the answer in
scientific notation.
1.248x10-2 : 7.8x10-7
[? ]x10

Answers

Answer: [tex]1.6\times 10^4[/tex]

Explanation:

Scientific notation is defined as the representation of expressing the numbers that are too big or too small and are represented in the decimal form with one digit before the decimal point times 10 raise to the power.

For example : 5000 is written as [tex]5.0\times 10^3[/tex]

In division , the result would contain the same number of significant digits as there in the least precise number , thus the answer would have 2 significant digits.

[tex]\frac{1.248\times 10^{-2}}{7.8\times 10^{-7}}=1.6\times 10^4[/tex]

does a periodic table indicate the occurrence of elements​

Answers

Answer:

no

Explanation:

it only shows the atomic number and basically the chemical behavior of the element

what is the difference between cells, tissues and organs

Answers

Answer:

A group of cells working together is defined as a tissue and several tissues working together comprise an organ.

Explanation:

Balance the reaction. A coefficient of "1" is understood. Choose option "blank" for the correct answer if the coefficient is "1." 2AgNO₃ + MgCl₂ 2AgCl + Mg(NO₃)₂

Answers

Answer:

The balanced equation is: 2AgNO₃ + MgCl₂ ------> 2AgCl + Mg(NO₃)₂

Explanation:

The law of conservation of mass states that in a normal chemical reaction, matter is neither created nor destroyed.

According to the law of conservation of mass, therefore, when a chemical reaction occurs, the mass of the products should be equal to the mass of the reactants. This implies that the amount of the atoms in each element in the chemical reaction remains the same before and after the reaction. A balanced chemical equation therefore,  is one that shows that the number of the atoms involved in the reactants side is equal to the number of atoms in the products side.

Considering the given reaction:

2AgNO₃ + MgCl₂ ------> 2AgCl + Mg(NO₃)₂

The amount in moles of each atom in the reaction is as follows;

Ag = 2 moles of atom on each side

N = 2 moles of atoms on each side

O = 6 moles of atoms on each side

Mg = 1 mole of atoms on each side

Cl = 2 moles of atoms on each side

Therefore, the above chemical equation is balanced.

Answer:

The equation is already balanced.

Explanation:

I NEED HELP PLEASE, THANKS! :)
A manufacturing company is trying to produce a lightweight but strong cart for use by home gardeners. Which metal—titanium (Ti), iron (Fe), or zinc (Zn)—would be the best for this application and why?

Answers

Answer:

Titanium; lowest density  

Explanation:

The cart would use the same volume of metal, no matter which one it was made of.

If weight were the only consideration, the company would choose the metal with the lowest density.

The values I find for the metals are

Ti   4.5 g/cm³

Fe  7.9 g/cm³

Zn  7.1  g/cm³

Titanium would be the best metal for this application.

 

Answer:

Titanium would be the best metal for this application because it is a low density metal that is still strong  and ductile

Explanation:

what is the mass of 3.01x1023 atoms of iron(atomic mass of fe=56)

Answers

Answer:

mass=279grams

Explanation:

GIVEN DATA

number of atoms=3.01×10^23

avogadro's number=6.022×10^22

molar mass of iron=56g/moles

TO FIND

mass in gram of iron=?

SOLUTION

by using the formula

mass in gram=(number of atoms÷avogdro's number)×molar mass

mass=(3.01×10^23÷6.022×10^23)×56

mass=0.499×56

mass=27.9grams=28 grams


is the study of the natural world through observation and experimentation.

Answers

Answer:

YES

Explanation:

The systematic study of the structure and behavior of the physical and natural world through observation and experiment.

15. Calculate the hydrogen ion concentration of a
solution whose pH is 2.4
A 3.6 x 0.01
B 2.5 x 0.0001
C 2.5 x 0.01
D 7.0 x 0.01​

Answers

Answer:

Explanation:

pH = − log [H+] , we can solve for [H+] as,

− pH = log [H+] ,

[H+] = 10^−pH,

so PH =2.4 in you case is

[H+] = 10^-2.4 =0.00398

The option are not correct it looks

If you wanted to perform a controlled experiment to test the effect of temperature on the pressure of a bicycle tire, which of the following would be necessary?

Answers

It would be the needle pressure gage temp check

Can the pH scale be utilized for all acids (Arrhenius, Bronsted-Lowry, and Lewis)? Give examples of substances from each definition category that can/cannot use the pH scale and explain your reasoning.

PLEASE ANSWER

Answers

Answer:

No

Explanation:

The pH scale is a scale graduated from 0-14 which shows the degree of acidity of alkalinity of a substance. The pH scale is graduated in such a way that 0-6.9 indicates acidity, 7.0 indicate a neutral substance, while a pH of 8-14 indicates alkalinity respectively.

There are three main definitions of acids/bases

- Arrhenius definition

-Brownstead-Lowry definition

-Lewis definition

Arrhenius explains acids as any substance that produces hydrogen ions as its only positive ion in solution while a base produces hydroxide ions as its only negative ion in solution. The pH scale is based on corresponding values of pH derived from aqueous solutions of these substances.

However, not all acids/bases produces hydrogen or hydroxide ions in solution. Brownstead-Lowry definition of acids and Lewis definition of acids could be extended to nonaqueous media where the pH can not be measured as there are no hydrogen or hydroxide ions present in the solution.

This implies that pH measurement may not apply to acids/bases in the all the categories of acids/bases hence it can not be utilized for all acids and bases.

Arrhenius - sodium carbonate

Brownstead-Lowry - concentrated HF

Lewis acid - AlCl3

Explain contribution of Mendleev for arrangement of elements in his periodic table

Answers

Answer:

Mendeleev arranged the elements in order of increasing relative atomic mass. When he did this he noted that the chemical properties of the elements and their compounds showed a periodic trend. He then arranged the elements by putting those with similar properties below each other into groups.

-- He left gaps for yet to be discovered elements

-- He switched the order of a few elements to keep the groups consistent

-- He was the first scientist to give the periodic law.

He noted that repeating patterns of behavior could be seen in the way elements combined with each other.He their properties. He is recognized as the father of the modern periodic table.**Hope it was right. And that it helped!**



Which ion can be both an oxidizing agent and reducing agent?

A) Sn2+

B) Cu2+

C) Al3+

D) Fe3+

Answers

Answer: a)  Sn 2+  

Explanation:A reducing agent is a substance  that can be oxidized when it loses electrons while An oxidizing agent is a substance that is reduced when it gains   electrons.

 Considering  Cu 2+,   Fe 3+, Al 3+, Here,  Cu 2+ can  be reduce to its Copper metal, same for  Al 3+ to Aluminium  metal  and Fe 3+  to Fe 2+ ion  and will not be oxidized further since they are in their most oxidized states. The three ions are acting as only oxidizing agents.

while Sn 2+ can be oxidized to become Sn 4+ and also  be reduced to become Sn metal  acting as a reducing agent and an oxidizing agent.

Describe how a polyploid is formed

Answers

In other words, the polyploid cell or organism has three or more times the haploid chromosome number. Polyploidy arises as the result of total nondisjunction of chromosomes during mitosis or meiosis. Polyploidy is common among plants and has been, in fact, a major source of speciation in the angiosperms.

Answer:

ExpPolyploidy is the heritable condition of possessing more than two complete sets of chromosomes. Polyploids are common among plants, as well as among certain groups of fish and amphibians. For instance, some salamanders, frogs, and leeches are polyploids. Many of these polyploid organisms are fit and well-adapted to their environments. In fact, recent findings in genome research indicate that many species that are currently diploid, including humans, were derived from polyploid ancestors (Van de Peer & Meyer, 2005). These species that have experienced ancient genome duplications and then genome reduction are referred to as paleopolyploids. This article discusses the mechanisms underlying polyploidy, and both the advantages and disadvantages of having multiple sets of chromosomes.

Mechanisms of Polyploidy

This diagram shows several pathways by which diploid species can transition to polyploid species and polyploid species can transition to diploid species. Each species is represented by an oval containing two or more colored circles. Each colored circle represents a complete set of chromosomes.

View Full-Size ImageFigure 1

Figure Detail

How does an organism become polyploid? Polyploids arise when a rare mitotic or meiotic catastrophe, such as nondisjunction, causes the formation of gametes that have a complete set of duplicate chromosomes. Diploid gametes are frequently formed in this way. When a diploid gamete fuses with a haploid gamete, a triploid zygote forms, although these triploids are generally unstable and can often be sterile. If a diploid gamete fuses with another diploid gamete, however, this gives rise to a tetraploid zygote, which is potentially stable. Many types of polyploids are found in nature, including tetraploids (four sets of chromosomes), hexaploids (six sets of chromosomes), and other chromosome-pair multiples

the particles with a negative charge are


1) protons
2)neutrons
3)electrons

Answers

Answer:

the particles with a negative charge are protons

I am sure it is electrons.

A certain man needed 400N of force to pull a load through a distance of 150cm in 8s . Calculatell i) the work done by man ii) the power developed by man

Answers

Answer:

a) 600 J

b) 75 W

Explanation:

Force= 400 N, distance = 150 cm = 1.5 m, time= 8s

a) Work is the product of force acting on an object and distance (or displacement). The S.I unit of work is the joules.

Work = force × distance = 400 × 1.5 = 600 J

b) Power is the amount of energy transferred per unit time. It is the ratio of work to time. The S.I unit of power is watt

Power = work/time = 600 / 8 = 75 W

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