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

CHEM HELP PLEASE

a reaction that has been calculated to produce 346 g of CH3OH actually produced 312 g of CH3OH. what is it's percent yield?

Answers

Answer:

90.2%

Explanation:

% yield = actual yield/ theoretical yield * 100%

% yield = (312/346)*100% = 90.2%

___and ___exert pressure on the walls of the vessel in which they are carried out


A) Solid, liquid and Gases

B) Gases and solids

C) Liquids and gases

D) Solid and gases

Answers

Answer:

C) Liquids and gases

Explanation:

The correct answer would be liquids and gases.

The molecules of liquids and gases move randomly when held in a container. The random movement causes a collision between the molecules of the liquids/gases and between the walls of the container, creating pressure in the process. This is unlike the molecules of solids that vibrate about fixed positions.

Hence, the correct option is C.

H3PO4 + Ca(OH)2 → Ca(H2PO4)2 + H2O

Answers

Given question is incomplete. The complete question is as follows.

Balance the following equation:

[tex]H_3PO_4 + Ca(OH)_2 \rightarrow Ca(H_2PO_4)_2 + H_2O[/tex]

Answer: The balanced chemical equation is as follows.

[tex]2H_3PO_4 + Ca(OH)_2 \rightarrow Ca(H_2PO_4)_2 + 2H_2O[/tex]

Explanation:

When a chemical equation contains same number of atoms on both reactant and product side then this equation is known as balanced equation.

For example, [tex]H_3PO_4 + Ca(OH)_2 \rightarrow Ca(H_2PO_4)_2 + H_2O[/tex]

Number of atoms on reactant side:

H = 5

P = 1

O = 6

Ca = 1

Number of atoms on product side:

H = 6

P = 2

O = 9

Ca = 1

In order to balance this equation, we will multiply [tex]H_3PO_4[/tex] by 2 on reactant side and we will multiply [tex]H_2O[/tex] by 2 on product side. Hence, the balanced chemical equation is as follows.

[tex]2H_3PO_4 + Ca(OH)_2 \rightarrow Ca(H_2PO_4)_2 + 2H_2O[/tex]

What is the molarity of a solution that contains 6 moles of NaCl in 3 L of solution?

a
2.0 M

b
0.5 M

c
0.25 M

d
18.0 M


Answers

Answer:

a

2.0 M

Explanation:

divide 6by 3

formula :  molarity=moles divided by volume of solutions

The ____ contains the highest concentration of ozone. (troposphere (exosphere ( stratosphere ( mesosphere

Answers

Answer:

the answer is stratosphere.

about 90% of ozone is found in the stratosphere.


Which is the electron configuration for bromine?

Answers

Answer:

first answer

Explanation:

atomic number of bromine is 35

[tex]1{s}^{2} 2 {s}^{2} 2 {p}^{6} 3 {s}^{2} 3 {p}^{6} 3 {d}^{10} 4 {s}^{2} 4 {p}^{5} [/tex]

Answer:

1s22s22p63s23p64s23d104p5

Explanation:

;)

I NEED HELP PLEASE, THANKS! :)

Explain the process of sublimation. Name one substance that sublimes at room temperature and pressure.

Answers

Answer:

Here's what I get  

Explanation:

Sublimation is the conversion of a solid directly to a gas, without passing through the liquid state.

It occurs when the molecules of a solid have absorbed enough heat (kinetic energy) for some molecules to overcome the attractive forces of their neighbours and escape directly into the vapor phase.

One substance that sublimes at room temperature and pressure is CO₂ (dry ice).

Naphthalene is a substance that sublimes at room temperature and pressure.

What do you mean the process of sublimation ?

Sublimation is defined as a process in which solid converts into gas directly without converting into liquid.

In the sublimation process, the reaction is an endothermic reaction, as the chemical bonds between molecules are broken down in order to release them into the air. Therefore ,the energy is released and so it is an endothermic reaction.

The heat or energy required to change the state from solid to gas is called the enthalpy of sublimation .Generally, it is expressed as KJ/m o l. Sublimation only occurs at pressures and temperatures .

Hence , Naphthalene is a substance that sublimes at room temperature and pressure.

Learn more about sublimation ,here:

https://brainly.com/question/9967928

#SPJ2


Which statement is a scientific law?
A.Scientists use genes to explain why evolution happens.
B.Genes are long patterns that are similar to computer codes.
C.A person’s traits are controlled by different forms of a gene.
D.The discovery of genes changed how scientists think about life.

Answers

Answer:

A.Scientists use genes to explain why evolution happens.

Explanation:

:)

How many moles of sodium hydroxide would react with 1 Mole of sulphuric acid?

Answers

Answer:

Two moles.

Explanation:

Sulphuric (sulfuric) acid [tex]\rm H_2SO_4[/tex] is a diprotic acid. When one mole of [tex]\rm H_2SO_4[/tex] molecules dissolve in water, two moles of [tex]\rm H^{+}[/tex] ions would be produced.

[tex]\rm H_2SO_4 \to 2\, H^{+} + {SO_4}^{2-}[/tex].

On the other hand, sodium hydroxide [tex]\rm NaOH[/tex] is a monoprotic base. When one mole of [tex]\rm NaOH[/tex] formula units dissolve in water, only one mole of hydroxide ions [tex]\rm OH^{-}[/tex] would be produced.

[tex]\rm NaOH \to Na^{+} + OH^{-}[/tex].

Note that [tex]\rm H^{+}[/tex] and [tex]\rm OH^{-}[/tex] react at a one-to-one ratio:

[tex]\rm H^{+} + OH^{-} \to H_2O[/tex].

As a result, it would take [tex]2\; \rm mol[/tex] of [tex]\rm OH^{-}[/tex] to react with the [tex]\rm 2\; mol[/tex] of [tex]\rm H^{+}[/tex] that was released when [tex]1\; \rm mol[/tex] of [tex]\rm H_2SO_4[/tex] is dissolved in water. Since one mole of [tex]\rm NaOH[/tex] formula units could produce only one mole of [tex]\rm OH^{-}[/tex], it would take [tex]\rm 2\; mol[/tex] of [tex]\rm NaOH[/tex] formula units to produce that [tex]2\; \rm mol[/tex] of [tex]\rm OH^{-}[/tex] for reacting with [tex]1\; \rm mol[/tex] of [tex]\rm H_2SO_4[/tex].

ANSWER IT CORRECTLY PLEASE!!
The Osmotic pressure of blood is 7.65 ATM at 310 k. An aqueous solution of glucose is isotonic with blood has the percentage by volume

a.5.41%
b.3.54%
c.4.53%
d.53.4%​

Answers

Answer:

Explanation:

Pv = n RT

P =7.65, T= 310K, for glucose n = moles= weight/molar mass= weight/180, R is gas constant

7.65* V =W/180 *0.0821 * 310

w/v= 7.65*180/0.0821*310 = 1377/25.45 = 54.10 =5.4%



Strontium, a group 2 element with an electron configuration of 1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^10 4p^6 5s^2 , will form a _____ ion in a chemical bond.


+1

+2

-1

-2

Answers

Answer:

Strontium, a group 2 element with an electron configuration of 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² , will form a +2 ion in a chemical bond.

Explanation:

An ionic bond is produced between metallic and non-metallic atoms, where electrons are completely transferred from one atom to another. During this process, one atom loses electrons and another one gains them, forming ions. Usually, the metal gives up its electrons forming a cation to the nonmetal element, which forms an anion.

So an ion is an atom or group of atoms that have an electric charge. A cation is an ion that has a positive charge.

The alkali metals in the earth (Elements IIA) lose two electrons to form a 2+ cation. Strontium is an alkali metal that loses the two electrons belonging to 5s², forming the +2 ion.

Answer:

+2

Explanation:

What is the answer to this ?

Answers

Answer:

12.78 or 12.80 mostly like 12.78

Explanation:

How do you solve this

Answers

Answer:

23.6°C

Explanation:

Step 1:

Data obtained from the question. This include the following:

Mass = 0.125kg = 0.125 x 1000 = 125g

Initial temperature (T1) = 22°C

Heat (Q) generated in 4.5mins = 835J

Specific heat capacity (C) of water = 4.184J/g°C

Change in temperature (ΔT) =?

Final temperature (T2) =?

Step 2:

Determination of the change in temperature, ΔT of water.

This can be obtained as shown below:

Q = MCΔT

835 = 125 x 4.184 x ΔT

Divide both side by 125 x 4.184

ΔT = 835 / (125 x 4.184)

ΔT = 1.6°C

Therefore, the change in temperature, ΔT is 1.6°C

Step 3:

Determination of the final temperature of water.

This can be obtained as follow:

Initial temperature (T1) = 22°C

Change in temperature (ΔT) = 1.6°C

Final temperature (T2) =?

Change in temperature (ΔT) = Initial temperature – Final temperature

ΔT = T2 – T1

1.6 = T2 – 22

Collect like terms

T2 = 1.6 + 22

T2 = 23.6°C

Therefore, the final temperature of the water is 23.6°C.


Oxygen is released into the atmosphere by _____.

respiration
photosynthesis
denitrification
fixation

Answers

Oxygen is released into the atmosphere by Photosynthesis

Answer:

your answer will be photosynthesis

Explanation:

Who was the second person to organize the elements on the periodic table and what property did he use to re-organize them?

Answers

Answer:

Dmitri Mendeleev

Explanation:

He was a Russian Scientist who decided to reorganize the periodic table after other notable scientists such as Antoine-Laurent Lavoisier had also tried to organize it based on the states of matter of the elements.

Mendeleev reorganized the period in the order of increasing atomic mass although there were some other modifications by modern scientists.

which accurately describes development?

Answers

Answer:

changing while growing

Explanation:

Answer: the answer is a

When naming acids, the term “hydro” is used then there are or are not (pick the correct one) any oxygens.

Answers

Answer:

There are no oxygen

Explanation:

Hydro is used when naming hydrogen compound and oxo is used when naming oxygen compound

Identify what is in that photo please!! (10 pts)

Answers

Answer:

Electromagnet

Explanation:

The top one would be the correct answer

name two bases which react with dillute sulfuric acid to give zinc sulfate

Answers

Answer:

Zinc Carbonate

Zinc Nitrate

Explanation:

12. Aditya is stacking some cups. The diagram above shows the cups before they touch each other. Use the information in the diagram to answer the question.

After the cups have been touching for a while, which of the two bottom cups will be cooler, and why?

Answers

Aditya would be the cooler person in this situation I think idk

Answer:

please give more clarification

What type of mixture is fog?
O A. A homogenous mixture of a solid in a gas
B. A heterogeneous mixture of a liquid in a gas
C. A homogenous mixture of a liquid in a gas
D. A heterogeneous mixture of a solid in a gas

Answers

Answer:

. A homogeneous mixture of a solid in a gas

Someone please help me with the second question ONLY

Answers

Answer:

no

Explanation:

this experiment could not be replicated, because there are no specific measurements. the details would not be the same because it does not include the type of paper used nor the diameter, width or length. A guess of the measurements would be the only way to replicate this experiment but other then that, no you cannot.

For neap tides, what must the angular alignment be between the sun, earth and moon?

Answers

Answer:

The angular alignment is 90 degrees

Explanation:

The neap tide is a type of tide which occurs around seven days after a spring tide. This type of tide happens twice every month.

The tide is usually moderate and it exists when the sun and moon are usually at right angles to each other when it occurs. A right angle is also known as 90 degrees which validates the tide occurring at an angle 90.

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:

Formamide decomposes at high temperature. If 0.186 mol of formamide (HCONH2) dissociates in a 2.16 L flask at 400 K, what are the concentrations of all species present at equilibrium at 400 K? (hint: calculate concentrations first) (b) What is the total pressure in the container at equilibrium?

Answers

Answer:

a) [COHNH₂] = 0.001 mol/L, [NH₃] = [CO] = 0.085 mol/L

b) 5.59 atm

Explanation:

a) The decomposition reaction of formamide is the following:

COHNH₂(d)  ⇆  NH₃(g) + CO(g)    

The equilibrium constant of the reaction above is:

[tex]K_{c} = \frac{[NH_{3}][CO]}{[COHNH_{2}]} = 4.84 (400 K)[/tex]

The initial concentration of formamide is:

[tex] C_{COHNH_{2}} = \frac{\eta}{V} = \frac{0.186 moles}{2.16 L} = 0.086 mol/L [/tex]

Where: η is the number of moles and V is the volume

Now, in the equilibrium the concentration of all species is:

COHNH₂(d)  ⇆  NH₃(g) + CO(g)  

0.086 - x              x             x

[tex] K_{c} = \frac{[NH_{3}][CO]}{[COHNH_{2}]} = \frac{x*x}{0.086 - x} [/tex]  

[tex] 4.84*(0.086 - x) -x^{2} = 0 [/tex]

By solving the above equation for x we have:

x = 0.085 mol/L = [NH₃] = [CO]

[COHNH₂] = 0.086 - 0.085 = 0.001 mol/L

Therefore, the concentrations of all species present at equilibrium at 400 K is [NH₃] = [CO] = 0.085 mol/L and [COHNH₂] = 0.001 mol/L.

b) To find the total pressure in the container we need to find first the constant Kp as follows:

[tex] K_{p} = K_{c}*RT^{\Delta n} [/tex]

Where R is the gas constant = 0.082 Latm/(Kmol), T is the temperature = 400 K and Δn = 1

[tex] K_{p} = K_{c}*RT^{\Delta n} = 4.84*(0.082*400)^{1} = 158.8 [/tex]

Now, the total pressure is:

[tex] p_{T} = p_{COHNH_{2}} + p_{NH_{3}} + p_{CO} [/tex]

The pressure of COHNH₂ can be found using Ideal Gas Law:

[tex] P = \frac{nRT}{V} = \frac{0.186 moles*0.082 L*atm/(K*mol)*400 K}{2.16 L} = 2.82 atm [/tex]

Using the equilibrium constant we can find the pressure of NH₃ and CO:

COHNH₂(d)  ⇆  NH₃(g) + CO(g)  

2.82 - x              x             x

[tex] K_{p} = \frac{P_{NH_{3}}*P_{CO}}{P_{COHNH_{2}}} [/tex]

[tex] 158.8*(2.82 - x) - x^{2} = 0 [/tex]

By solving the above equation for x we have:

[tex] x = P_{NH_{3}} = P_{CO} = 2.77 atm [/tex]

[tex] P_{COHNH_{2}} = 2.82 - 2.77 = 0.05 atm [/tex]

Thus, the total pressure is:

[tex] p_{T} = p_{COHNH_{2}} + p_{NH_{3}} + p_{CO} = (0.05 + 2.77 + 2.77) atm = 5.59 atm [/tex]

Hence, the total pressure in the container at equilibrium is 5.59 atm.

I hope it helps you!

Which of the following symbols would be included in the noble gas notation for an element that had valence electrons in the
5s subshell?
A) Ar
B) Kr
C) Хе
D) Rn

Would be appreciated if I could get a quick answer. Thank you in advance.

Answers

Answer: C.) Xe

Explanation: To figure out the answer go to the Noble Gas Family and count down 5 elements.

According to the electronic configuration the symbol which would be included in the noble gas notation for an element that had valence electrons in the 5 s subshell is xenon  .

What is electronic configuration?

Electronic configuration is defined as the distribution of electrons which are present in an atom or molecule in atomic or molecular orbitals.It describes how each electron moves independently in an orbital.

Knowledge of electronic configuration is necessary for understanding the structure of periodic table.It helps in understanding the chemical properties of elements.

Elements undergo chemical reactions in order to achieve stability. Main group elements obey the octet rule in their electronic configuration while the transition elements follow the 18 electron rule. Noble elements have valence shell complete in ground state and hence are said to be stable.

Learn more about electronic configuration,here:

https://brainly.com/question/29757010

#SPJ5

A 315-mL bag of potato chips is packaged at sea level (1.00 atm) where the temperature is 25oC. If this bag of chips is transported to Denver (where the pressure is 0.775 atm and the temperature is 18oC), what will the new volume of the bag be?

Answers

Answer:

THE NEW VOLUME AT A PRESSURE OF 0.775 atm AND TEMPERATURE OF 18 °C IS 0.397 L

Explanation:

Using the combined gas equation

P1V1/T1 = P2V2/ T2

P1 = 1 atm

VI = 315 mL = 315 / 1000 L = 0.315 L

T1 = 25°C  25 + 273 K = 298 K

P2 = 0.775 atm

T2 = 18 °C = 18 + 273 K = 291 K

V2 = Unknown

Substituting the values into the equation, we obtain:

V2 = P1V1 T2/ P2 T1

V2 = 1 * 0.315 * 291 / 0.775 * 298

V2 = 91.665 / 230.95

V2 = 0.3969 L

The new volume at the given change in conditions is 0.397 L

How do forces between particles in solids compare to forces in the other
states of matter?
O A. The forces in solids are stronger than forces in liquids and gases.
O B. The forces in solids are weaker than forces in liquids and gases.
O C. The forces in solids are stronger than forces in liquids but weaker
than forces in gases.
D. The forces in solids are weaker than forces in liquids but stronger
than forces in gases.

Answers

Answer:

the answer is A

Explanation:

Forces are the intermolecular interaction between the matter. Forces present in a solid are strongest. Thus, option A is correct.

What are the phases of matter?

The matter is any substance that occupies a volume. Matter can be a solid, gas, or liquid. The solid phase particles are tightly closed to each other making the force strong.

The particles of liquids that are not too compact are a little free and in gases, the particles are very free, which makes the bonding and the force the weakest.

Therefore, option A. the solids have the strongest intermolecular bonding.

Learn more about intermolecular forces here:

https://brainly.com/question/14155077

#SPJ2

Which substance is a mixture? Table salt, gasoline, aluminum, or carbon dioxide.

Answers

Answer:

gasoline

Explanation:

Gasoline is the mixture because it takes several chemicals mixing together to make it.

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

Answers

Answer:

N = n× l

N = number of entities

n= moles

l = Avogadro's constant = 6.023 × 10^23

3.01 × 10^ 23 = n * 6.023 × 10^23

n = 3.01 × 10^23/6.023 × 10^23

n= 0.5moles

Molar mass = mass/ number of moles

Molar mass = 56

mass = 56 × 0.5

= 28g

Hope this helps.

Other Questions
g It is known that 20% of products on a production line are defective. Products are inspected until first defective is encountered. a) What is the probability that the experimenter must inspect six products Which geometric series converges? Suppose that the following two classes have been declared public class Car f public void m1) System.out.println("car 1"; public void m2) System.out.println("car 2"); public String toString) f return "vroom"; public class Truck extends Car public void m1) t System.out.println("truck 1"); public void m2) t super.m1); public String toString) t return super.toString) super.toString ); Write a class MonsterTruck whose methods have the behavior below. Don't just print/return the output; whenever possible, use inheritance to reuse behavior from the superclass Methog Output/Return monster 1 truck1 car 1 m2 toString "monster vroomvroom'" Type your solution here: Ethanol, , boils at 78.29 C. How much energy, in joules, is required to raise the temperature of 2.00 kg of ethanol from 26.0 C to the boiling point and then to change the liquid to vapor at that temperature? (The specific heat capacity of liquid ethanol is 2.44 J/g K, and its enthalpy of vaporization is 855 J/g.) For the dilation with center (0, 0) shown on the graph, your friend says the scale factor is 4.Is your friend correct or no? If he is incorrect, What is the correct scale factor? and what mistake did he likely make? 30. To enhance healing of the bruise you needto keep the injured area as low as possibleO TRUEFALSE Jayne polled 50 students about their preferred after-school sport and then recorded the data in the table below. Which sport is more popular? A. You can use a relative frequency table to examine how data sets are related by comparing percentages.B. Row and column relative frequency tables tell you the same information as total relative frequency tables.C. A column relative frequency table helps compare data in two different rows.D. In a column two-way relative frequency table, each column totals 100%. The number of newly reported crime cases in a county in New York State is shown inthe accompanying table, where x represents the number of years since 2001, and yrepresents number of new cases. Write the linear regression equation that representsthis set of data, rounding all coefficients to the nearest hundredth. Using thisequation, find the projected number of new cases for 2013, rounded to the nearestwhole number. Paragraph: sea captains looked at the night sky as they sailed on the ocean they needed to know which way was north. There is one star that is always true north. Its called the North Star. It guided sailors in the way. Whats the main idea ?Detail 1 Detail 2 United Kingdoms history Ahoy starting from rest moves with a distance of 200m in 10 seconds...Find the magnitude of acceleration Suppose the manager of a restaurant in a commercial building has determined that the proportion of customers who drink tea is 24%. Based on a random sample of 300 customers, what is the standard error for the sampling distribution of the sample proportion of tea drinkers? A researcher investigates a recently discovered species of plant. The plant has vascular tissues and exhibits a sporophyte and a gametophytegeneration, but lacks seeds. How should the researcher classify the plant? I dont know this one What is the square root of -1? Please help me asap! HELP ASAP PLEASEAre the bases of the prism equilateral triangles? Why or why not? Note: The bases of a triangular prism are triangles.For this prism to be a right prism, all the lateral faces must be rectangles. Is enough information given to prove the lateral faces are rectangles? Why or why not? Why can't you use the product of powers rule to simplifythis expression? Explain.3^4.2^8 Sidney made $35 less than four times Caseys weekly salary. If x represents Caseys weekly salary, write an expression for Sidneys weekly salary. Which of the following gives all of the sets that contain sqare root 91 the set of all irrational numbers 2.the set of all natural numbers, the set of all whole numbers, and the set of all integers3. the set of all integers, the set of all rational numbers, and the set of all real numbers4. the set of all natural numbers, the set of all whole numbers, the set of all integers, the set of all rational numbers, and the set of all real numbers