Boron has an average atomic mass of 10.81. One isotope of boron has a mass of 10.012938 and a relative abundance of 19.80%. The other isotope has a relative abundance of 80.20%. What is the mass of that isotope? Report to two decimal places. amu

Answers

Answer 1

Answer:

11.01 amu

Explanation:

19.8% • 10.012938 = 1.982561724

10.81 - 1.982561724 = 8.827438276

8.827438276/80.2% = 11.0067808928

Answer 2

Answer:  11.01 amu

Explanation:


Related Questions

how to covert ethanol into 2-butanol.(show reaction)​

Answers

Explanation:

Conversion -

Ethanol to 2-butanol

CH₃–CH₂–OH → CH₃–CH₂– CH(OH)–CH₃

Explaination -

CH₃–CH₂–OH + HCl → CH₃–CH₂– Cl + H₂O

Now,

CH₃–CH₂– Cl + 2Na + Cl–CH₂–CH₃ → CH₃–CH₂–CH₂–CH₃ + 2NaCl (wurtz reaction)

Now,

CH₃–CH₂–CH₂–CH₃ + Cl₂ → CH₃–CH₂–CH₂–CH₂–Cl + HCl (Halogenation)

Now,

CH₃–CH₂–CH₂–CH₂–Cl + KOH (alc.) → CH₃–CH₂–CH=CH₂ + KCl + H₂O

Now,

CH₃–CH₂–CH=CH₂ + H₂O → CH₃–CH₂–CH(OH)–CH₃ (Hydration of alkene by MR addition rule)

What was the test or tests that made you decide if you compound was an aldehyde or a ketone and why?

Answers

Answer:

Tollen's test or silver mirror test is use to distinguish between ketone and aldehyde.

Explanation:

Tollen's test is use to distinguish aldehyde from ketone because Tollen reagent consist of silver nitrate and ammonia and it oxidized aldehydes to carboxylic acid and the silver Ag+ is reduced to solid silver Ag. It form a inner film wall on the tube that look like mirror. Ketone do not react with Tollen reagent and therefore does not form silver mirror on the tube wall.

Caffeine, a stimulant found in coffee and soda, has the following elemental composition: 49.48% carbon, 5.19% hydrogen, 16.48% oxygen and 28.85% nitrogen. The molar mass of caffeine is 119.19 g/mol. Determine the molecular formula of caffeine.

Answers

Answer:

Explanation:

C = 49.48

H = 5.19

O = 16.48

N = 28.85

ratio of moles

= 49.48 / 12 : 5.19 / 1 : 16.48 / 16 : 28.85 / 14

= 4.123 : 5.19 : 1.03 : 2.06

= 4 : 5 : 1 : 2

so the empirical formula = C₄ H₅O N₂

Let molecular formula = (  C₄ H₅ON₂ )ₙ ,

n ( 48 + 5 + 16 + 28 ) = 119.19

97 n = 194.19

n = 2 ( approx )

molecular formula = C₈ H₁₀O₂ N₄

How do living systems follow the laws of conservation of mass?

Answers

Answer:

they use it when a living organism dies.

Explanation:

when d organism decomposes carbon is released that enters back into d earth. this follows d law of mass

Which is a chemical property of soda ash?

Answers

Explanation:

A chemical property of soda ash is, it is a alkaline compound

A sample of 6.44 g of napthalene (C10H8) is dissolved in 80.1 g of benzene (C6H6). Calculate the percent by mass of napthalene in this solution.​

Answers

Answer:

7.44%

Explanation:

[tex]\frac{6.44}{6.44+80.1} *100=7.44[/tex]

s this statement true or false? All worms belong to the same phylum.

Answers

Answer:

FALSE.

Explanation:

The right answer is false. There are three different groups of phylum for worms.

Hope this helped!

Answer:

FALSE

there are like 3 different phylum

Explanation:

Hope this helps!

if so

please mark Brainlist!!

thx

Calculate pCl for the titration of 100.0mL of 0.1000 MCI with 0.1000 M
AgNO3 for the addition of 0.00 and 20.00 mL AgNO3.

Answers

the titration is the most important part in determining whether

2. Combining 0.242 mol Fe2O3 with excess carbon produced 10.2 g Fe.

Fe2O3+3C⟶2Fe+3CO

(a) Actual yield of Fe mole

(b) percentage mole

(c) theoretical yield of iron mmoles

Answers

actual yield = 0.182 mole

theoretical yield : 0.484 mole

percentage mole(% yield)=37.6%

Further explanation

Percent yield is the comparison of the amount of product obtained from a reaction with the amount you calculated

General formula:

Percent yield = (Actual yield / theoretical yield )x 100%

An actual yield is the amount of product actually produced by the reaction. A theoretical yield is the amount of product that you calculate from the reaction equation according to the product and reactant coefficients

Reaction

Fe₂O₃+3C⟶2Fe+3CO

a. actual yield of Fe mole

10.2 g produced

[tex]\tt mol~Fe=\dfrac{10.2}{56}=0.182[/tex]

b. percentage mole and theoretical yield

0.242 mol Fe₂O₃ = 2 x 0.242 mol Fe = 0.484 mol (theoretical yield)

percentage yieldpercentage mole)

[tex]\tt \dfrac{0.182}{0.484}=0.376=37.6\%[/tex]

Why does water have a much higher boiling point than methane even though water (H20) and methane (CH4) molecules are approximately the same size?
A. Only metallic bonds exist between methane molecules.
B. Only Van der Waals forces exist between water molecules.
C. Only metallic bonds exist between water molecules.
D. Only Van der Waals forces exist between methane molecules.​

Answers

Answer:

Water has a higher boiling point because the hydrogen bonds that form water molecules are stronger than the Van der Waals interactions among methane molecules, therefor more energy must be provided in order to break the hydrogen bonds and allow the water molecules to escape the liquid state.

Explanation:

Water has a much higher boiling point than methane because only Van der Waals forces exist between methane molecules.

What are chemical bonds?

Chemical bonds are forces of attraction between ions, molecules, and atoms.

There are different types of bonds present

Covalent bonds are the strongest bonds.

The molecules of water are joined by a hydrogen bond, thus its boiling point is high.

The molecules of Methane are attached by the van der Waals force, and it is weaker than the hydrogen bond.

Thus, methane has a lower boiling point than water.

Weaker bonds easily get broken.

Thus, the correct option is D.

Learn more about Chemical bonds

https://brainly.com/question/6071754

describe, in terms of the motion of particles in an object, how heat conduction transfers energy between objects or from one part of an object to another part at a lower temperature.

Answers

Answer:

Molecular movement

Explanation:

When an object gets hotter, its molecules gain more kinetic energy and then move faster. Therefore, the fast-moving molecules will cause those around them to move faster as well, and the colder (or more slow-moving molecule object) object or part is heated up.

PLS GIVE BRAINLIEST

A chemist prepares a solution of magnesium fluoride MgF2 by measuring out 0.0113μmol of magnesium fluoride into a 450.mL volumetric flask and filling the flask to the mark with water. Calculate the concentration in /mmolL of the chemist's magnesium fluoride solution. Round your answer to 3 significant digits.

Answers

Answer:

2.51x10⁻⁵ mmol MgF2/L

Explanation:

To find the concentration in mmol / L we need to convert μmol to mmol (1000μmol / 1mmol) and mL to Liters (1000mL / 1L) as follows:

μmol MgF2:

0.0113μmol MgF2 * (1mmol / 1000μmol) = 1.13x10⁻⁵ mmol MgF2

Liters solution:

450mL * (1L / 1000mL) = 0.450L

Concentration in mmol/L:

1.13x10⁻⁵ mmol MgF2 / 0.450L =

2.51x10⁻⁵ mmol MgF2/L

A sample of neon gas occupies 5.5 liters at 20°C and 650 mmHg. What is the expected volume of the gas at S.T.P.​

Answers

Answer:

V₂ = 4.4 L

Explanation:

Given data:

Initial volume = 5.5 L

Initial pressure = 650 mmHg (650/760 =0.86 atm)

Initial temperature = 20 °C (20 +273 = 293 K)

Final temperature = 273 K

Final volume = ?

Final pressure =  1 atm

Solution:

Formula:  

P₁V₁/T₁ = P₂V₂/T₂  

V₂ =  P₁V₁T₂/T₁ P₂

V₂ = 0.86 atm× 5.5 L × 273 K / 293 k × 1 atm

V₂ = 1291.29 atm.K.L / 293 k.atm

V₂ = 4.4 L

A student wants to use cookies to make a model of the genetic makeup of the offspring of asexual reproduction. He has vanilla cookies and chocolate cookies available. How can he make his model?
A.
Put chocolate cookies in a row with arrows between them showing the progression from parent to offspring.
B.
Use one chocolate cookie parent with arrows showing that it produces vanilla cookies and chocolate cookies as offspring.
C.
Use chocolate cookies and vanilla cookies as the parents, and vanilla cookies and chocolate cookies as the offspring.
D.
Use chocolate cookies and vanilla cookies as parents, and combine half a vanilla cookie and half a chocolate cookie for the offspring.

Answers

Answer:

i am not sure but it seems D is the best

Answer:

A

Explanation:

It seems to be the most logical. My reasoning is that for B when it uses one parent cookie that produced genetically different offspring. That is what makes it incorrect. The other two options involve two parents which means that the reproduction would be sexual. A. would be the closest to the answer.

Please let me know if this is correct! Hope it helped.

2. What group is Ballardium located? (Bu) *

Answers

Answer:

This question appears incomplete

Explanation:

There is no such element known as "Ballardium (Bu)" in the periodic table. However, there are elements with a bit of similarity in spellings and pronunciation such as Beryllium (Be) which is found in group 2 (meaning it is an alkali earth metal), Berkelium (Bk) which is an actinide (meaning it is radioactive) and Vanadium (V) which is found in group 5 of the periodic table (meaning it's a transition metal).

Calculate the pH after 20.0% (by moles) of the benzoic acid is converted to benzoate anion by addition of a strong base. Use the dissociation equilibrium to calculate the pH. pH = ________

Answers

Answer:

pH = 4.79

Explanation:

The equilibrium of benzoic acid, BH, is:

BH ⇄ B⁻ + H⁺

Where B⁻ is benzoate anion

Where the dissociation equilibrium, Ka, is:

Ka = 6.46x10⁻⁵ = [B⁻] [H⁺] / [BH]

If 20.0% is B⁻, 80.0% is BH, replacing:

6.46x10⁻⁵ = [20.0%] [H⁺] / [80.0%]

1.615x10⁻⁵ = [H⁺]

As pH = -log [H⁺]

pH = 4.79

An energy bill indicates that the customer used 1024 kWh in July. How many joules did the customer use?

Answers

Answer:

3,686,400,000 Joules

Explanation:

Energy = 1024 kWh

To be converted to Joules.

The relationship between kwh and joules is;

1 kilowatt-hour = 3600000 J

So we have;

1 = 3600000

1024 = x

x = 1024 * 3600000

x = 3,686,400,000 Joules

2 or more forces that are not equal and opposite of one another can cause change in motion

A. Balanced force

B.friction

C.gravitational force

D.unbalanced force

Answers

Answer:

D unbalanced force

Explanation:

i think

By what mechanism does cyclohexanol react when treated in concentrated sulfuric acid/phosphoric acid and what compound results?

Answers

Answer:

The mechanism is E1 and the product is cyclohexene

Explanation:

Attached to this answer is an image of the reaction mechanism of the reaction between cyclohexanol and concentrated sulfuric acid/phosphoric acid. The acid (H3O^+) acts as catalyst.

We can see that the first step in the mechanism is the protonation of the -OH group of the alcohol. This is followed by loss of water molecule which is a good leaving group.

The water now acts as a Lewis base by abstracting a proton from the substrate, forming cyclohexene and regenerating the acid catalyst.

Aluminum has a density of 2.70 g/mL. Calculate the mass (in grams) of a piece of aluminum having a volume of 238 mL .

Answers

Answer:

mass in gram = 642.6 g

Explanation:

Given data:

Density of aluminum = 2.70 g/mL

Volume of aluminum = 238 mL

Mass in gram = ?

Solution:

Density:

Density is equal to the mass of substance divided by its volume.  The symbol used for density is called rho. It is represented by ρ. However letter D can also be used to represent the density.

SI unit of density is Kg/m3.

Other units are given below,

g/cm3, g/mL , kg/L

Formula:

d =m/v

d = density

m=mass

V=volume

Now we will put the values in formula.

2.70 g/mL = m/ 238 mL

m = 2.70 g/mL × 238 mL

m = 642.6 g

A gas has a volume of 6.00 liters at a temperature of 27° C and a pressure of 1,00 atm. What is the volume of the gas, in liters, at a temperature of 327°C and a
pressure of 3.00 atm?

Answers

We are given:

P1 = 1 atm                 P2 = 3 atm

T1 = 300 K               T2 = 600 K

V1 = 6 L                    V2 = v L

Finding the final Volume:

From the ideal gas equation:

PV = nRT

since in the given scenario, the universal gas constant (R) and number of moles(n) are constant

So, for both the cases, the value of n*R will be a constant k

Hence, we can write that:

PV / T = k        [where k is a constant]

Since the constant 'k' is the same for both the cases, we can write that:

P1V1 / T1 = P2V2 / T2

replacing the variables

1 * 6 / 300 = 3 * v / 600

1/50 = v / 200

v = 200/50

v = 4 L

Therefore, the volume of the gas at 600K and 3 atm will have a volume of 4 L

6 List What are two advantages and two
limitations of physical models?
Plz help

Answers

Answer:

Physical models can represent objects or systems that are too small, too big, or too far away to study. They are way easier, cheaper, and safer to work with or use when compared to the real objects that they represent.

Explanation:

Which letter indicates the asthenosphere

Answers

Answer:

q

Explanation:

A gas has a density of 1.57 g/L at 40.0 °C and 2.00 atm of pressure. What is the identity of the gas?

Answers

Answer:

Ne is the identity of the gas

Describe the three kinds of particles found in atoms. Where are they located in the atom and what are their charges?

Answers

Proton(positive charge), Neuron(neutral charge), electron(negative charge).

A ball was massed in a dish. The total mass was 15.6 grams. Treball was placed in a
cylinder containing 26.7 ml of water. The new water level was 38.9 ml. If the mass of the dish is 1.03 grams, what is the mass of the ball?

Answers

Answer:

14.57g

Explanation:

Given parameters:

Mass of dish + ball  = 15.6g

Initial volume of water in the cylinder  = 26.7mL  

Final volume of water in the cylinder  = 38.9mL

Mass of dish = ?

Unknown

Mass of the ball = ?

Solution;

 Since the mass of ball and dish is 15.6g,

 Mass of the ball  =Mass of ball + dish  - mass of the dish

 Insert the parameters and solve;

 Mass of the ball  = 15.6g  - 1.03g  = 14.57g

Please help me please i will mark you brainliest. In the nucleus of an atom, there are 17 protons and 18 neutrons. What is the atomic number? What is the atomic mass? How many electrons are there? Be sure to answer all 3 questions.

Answers

Answer:

i can only help with 2 :( atimic mass is: 35.453  and number of electrons is:17

Explanation:

8. ______________ and _____________ are located in the nucleus.

Answers

Answer:

protons and neutrons are located in the nucleus.

Help for chem/physics

Answers

Answer:

first and 3rd are ur answers

Write the balanced chemical equation for the following reaction. Phases are optional. Solid iron(I) oxide reacts with hydrogen gas to form solid iron and liquid water. 2Fe+3H,Ol Fe,O,+ 3H2 â 2Fe+ 3H2O(I)

Answers

Answer:

[tex]Fe_2O_3(s)+3H_2(g)\rightarrow 2Fe(s)+3H_2O(l)[/tex]

Explanation:

Hello!

In this case, when writing chemical reactions from the given names we must make sure we know the proper formula for each reacted and produced species; thus, since solid iron (III) oxide is [tex]Fe_2O_3[/tex], hydrogen gas is [tex]H_2[/tex], solid iron is Fe and liquid water is just [tex]H_2O[/tex], we can write:

[tex]Fe_2O_3(s)+H_2(g)\rightarrow Fe(s)+H_2O(l)[/tex]

However, since different amount of atoms of iron, hydrogen and oxygen are present at each side of the equation, we balance it by adding the following coefficients to each molecule:

[tex]Fe_2O_3(s)+3H_2(g)\rightarrow 2Fe(s)+3H_2O(l)[/tex]

And now it is balanced with two iron atoms, three oxygen atoms and six hydrogen atoms at both reactants and products.

Best regards!

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