Element Z has 2 isotopes. A sample of element Z contains 19% Z234 and 81% Z236. What is the average atomic mass of the element Z?

Answers

Answer 1

Answer:

Wt Avg of the two isotopes = 235.62 amu

Explanation:

Given:

                                    abundance

Isotope     %      fractional     mass (amu)         Wt. Avg. Contributions

Z234        19%        0.19              234                (0.19)(234) = 44.46 amu

Z236        81%        0.81              236                (0.81)(236) = 191.16 amu

Collective Wt. Avg. of all isotopes = ∑ Wt. Avg. Contributions

= 44.46 amu + 191.16 amu = 235.62 amu


Related Questions

A 25.225 g sample of aqueous waste leaving a fertilizer manufacturer contains ammonia. The sample is diluted with 75.815 g of water. A 14.842 g aliquot of this solution is then titrated with 0.1068 M HCl . It required 29.99 mL of the HCl solution to reach the methyl red endpoint. Calculate the weight percent NH3 in the aqueous waste

Answers

Answer:

1.43 (w/w %)

Explanation:

HCl reacts with NH3 as follows:

HCl + NH3 → NH4+ + Cl-

1 mole of HCl reacts per mole of ammonia.

Mass of NH3 is obtained as follows:

Moles HCl:

0.02999L * (0.1068mol / L) = 3.203x10-3 moles HCl = Moles NH3

Mass NH3 in the aliquot:

3.203x10-3 moles NH3 * (17.031g / mol) = 0.0545g.

Mass of sample + water = 22.225g + 75.815g = 98.04g

Dilution factor: 98.04g / 14.842g = 6.6056

That means mass of NH3 in the sample is:

0.0545g * 6.6056 = 0.36g NH3

Weight percent is:

0.36g NH3 / 25.225g * 100

1.43 (w/w %)

If 19.2 grams of O2 reacts with iron to form iron oxide how much iron was used in the reaction? use the equation 4Fe + 3O2 — 2Fe2O3 to help

Answers

Answer:

44.8g

Explanation:

The reaction equation is given as:

        4Fe + 3O₂  →  2Fe₂O₃

Given:

Mass of O₂   = 19.2g

Unknown:

Amount of iron used  =?

Solution:

To solve this problem, we adopt the mole concept.

   Since we know the mass of O₂;

         Number of moles  = [tex]\frac{mass}{molar mass}[/tex]  

 Molar mass of  O₂ = 2(16)  = 32g/mol

           Number of moles = [tex]\frac{19.2}{32}[/tex]   = 0.6moles

From the balanced reaction equation;

           4 moles of Fe will react with 3 moles of O₂

          0.6moles of O₂ will react with [tex]\frac{0.6 x 4}{3}[/tex]   = 0.8mole of Fe

Mass of Fe  = number of moles x molar mass

                    = 0.8 x 56

                     = 44.8g

the number of elements in 2CH4

Answers

Answer:mnedd kfj

Explanation:

fr rb r

Sonar uses ____________ waves to tell how ____________things are in the water.

Answers

Sonar uses [sound] waves to tell how [far away] things are in the water.

Which pair of atoms are isotopes ?

Answers

Answer:

If two atoms have different numbers of protons, they are different elements. However, if two atoms have the same number of protons, but different numbers of neutrons we refer to them as isotopes. Two terms we use to identify nuclides (isotopes) are atomic number and mass number.

Explanation:

Your Welcome!

To see the number of atoms of an element in a given molecule we need to multiply stoichiometry to the number that is written on the foot of the element that is stoichiometry. Therefore, in below given ways we can identify isotopes.

What is atom?

Atom is the smallest particle of any element, molecule or compound. Atom can not be further divided. Atoms contains nucleus in its center and electron that revolve around the atom in fixed orbit.

In the nucleus, proton and neutron are present. Electron has -1 charge while proton has +1 charge. Neutron is neutral that is it has no charge. So overall the charge of nucleus is due to only proton, not by neutron.

Differing elements exist when two atoms contain different numbers of protons. If two atoms contain the same amount of protons but differing numbers of neutrons, they are referred to be isotopes.

Therefore, in above given ways we can identify isotopes.

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each substance in a solution mixture is visible to the naked eye? True or False

Answers

False
In a solution mixture, the particles are very small. You won’t be able to see them

a solution is made by dissolving 25g of nacl in 300g of water. What is the mass percentage

Answers

Answer:

0.83 bar

That is

23/300*100

=0.83 bar

Identify the true statements about introns.a- they code for polypeptide proteinsb- they have a branch site located 20 to 50 nucleotides upstream of the 3' splice sitec- they end with the nucleotides AG at the 3' endd- they begin with the nucleotides GU at the 5' ende- they tend to be common in bacterial genes

Answers

Answer:

The answer is "Option b, c, and d".

Explanation:

In such a gene, Autosomes are also the sequence for code and transposable elements, not the series of encoding. Through the expression of genes, such fragments of its introns are split through protein complexes throughout the translation process. There has been no kenaf fiber in the genomes of prokaryotic cells.

An object with the mass of 2300 g has a force of 6.2 Newton's applied to it. What is the resulting acceleration of the object?

Answers

Answer:

[tex]\boxed {\boxed {\sf a\approx 2.7 \ m/s^2}}[/tex]

Explanation:

Force is equal to mass times acceleration.

[tex]F=m*a[/tex]

By dividing both sides by m, we rearrange the formula for a (acceleration).

[tex]\frac{F}{m} =a[/tex]

The force is 6.2 Newtons, but we can convert the units to make the problem easier later on.

A Newton is equal to 1 kg*m/s², so 6.2 N is equal to 6.2 kg*m/s².

The mass is 2300 grams, but we need to convert it to kilograms.

To convert grams to kilograms, divide by 1,0002300 g/1000= 2.3 kg

[tex]F= 6.2 \ kg*m/s^2\\m=2.3 \ kg[/tex]

Substitute the values into the formula.

[tex]a=\frac{6.2 \ kg*m/s^2}{2.3 \ kg}[/tex]

Divide. Note that the kilograms or "kg" will cancel each other out (this is why we converted the units).

[tex]a=\frac{6.2 \ m/s^2}{2.3 \ }[/tex]

[tex]a=2.69565217 \ m/s^2[/tex]

Round to the nearest tenth. The 9 in the hundredth place tells us to round up to 2.7

[tex]a\approx 2.7 \ m/s^2[/tex]

The acceleration is about 2.7 meters per second squared.

How does the wind pattern during the day compare with the wind pattern at night?​

Answers

U know with the air filter for the next one ☝️ the call on

Which fossil fuel is made when plants from swamps are covered, pressed, and heated for millions of years? A Coal B Petroleum C Natural Gas D Nuclear

Answers

Answer:

A: COAL

Explanation:

Coal was created hundreds of millions years ago. When prehistoric plant life died and sank to the bottom of the swamp and was covered by layers of sediment.

Is this chemical equation balanced? yes or no

Mg + 2O ---> 2MgO

Answers

Answer:

yes

Explanation:

So the balanced equation is 2 Mg + O 2 2 MgO.. ... Example: 2Mg + O2 -> 2MgO Magnesium and oxygen combine to form the compound magnesium oxide.

Thus, to balance the O2 we put a 2 in front of the MgO. However, now there are 2 Mg's in the products and only one Mg in the reactants. To balance the Mg we then put a 2 in front of the Mg in the reactant. All atoms are now balanced in the reaction

Answer:

Yes.

Explanation:

Oxygen has 2 atoms, and so does Magnesium.

Hope this helped! Have a good night!

Calculate the mass of butane needed to produce 60.6 g of carbon dioxide.

Answers

Answer:

You take the mass of carbon dioxide, 56.8g, divide by its molar mass, 44.01g/mol, to produce the moles of carbon dioxide. This is multiplied by the molar ratio of butane/CO2, (2/8) = 1/4, which gives the moles of butane required to produce the carbon dioxide.

Explanation:

go to google

The ion formed by an atom of sulfur when it gains two electrons is called a:

Do not answer cation or anion​

Answers

Answer:

sulfide ion

Explanation:

however, when non-metalic elements gain electrons to form anions the end of their name is change to "-ide".foe example, a flourin atom gains one electronto become a flouride ion(F`) and sulfur gains two electrons to become a sulfide ion(s^2)

208
11- Predict the basicity of H2SO4 in the following reaction.
NaOH + H2SO4 – NaHSO4 + H20

Answers

Answer:

1

Explanation:

1 hydrogen is displaced from H2so4 in the reaction

Just enough 0.500 M HCl is added to 30.0 mL of 2.5 M NH3 to reach the equivalence point. The Kb of NH3 = 1.8 X 10-5
Write the balanced equation for this reaction.




What volume of 0.500 M HCl solution was added?



What is the molarity of the salt produced from the neutralization reaction?




What is the pH of the solution at the equivalence point?

Answers

a.NH₃+HCl⇒NH₄Cl

b.volume HCl=150 ml

c. pH=4.82

Further explanation

Reaction

NH₃+HCl⇒NH₄Cl

The equivalence point⇒mol NH₃=HCl

Titration formula :

M₁V₁n₁=M₂V₂n₂(n=acid base valence, NH₃=HCl=1)

mol NH₃

[tex]\tt 2.5\times 30=75~mlmol[/tex]

mol HCl=75 mlmol

Volume HCl :

[tex]\tt \dfrac{75}{0.5}=150~ml[/tex]

Volume total :

[tex]\tt 150+30=180~ml[/tex]

molarity of salt(NH₄Cl)

mol NH₄Cl=mol NH₃=75 mlmol=0.075 mol

[tex]\tt M=\dfrac{0.075}{0.180}= 0.42[/tex]

pH of solution

Dissociation of NH₄Cl at water to find [H₃O⁺]

[tex]\tt NH_4+H_2O\rightarrow NH_3+H_3O^+[/tex]

ICE at equilibrium :

0.41-x            x        x

Ka(Kw:Kb)= 10⁻¹⁴ : 1.8.10⁻⁵=5.6.10⁻¹⁰

[tex]\tt Ka=\dfrac{NH_3.H_3O}{NH_4}=\dfrac{x^2}{0.41}[/tex]

[H₃O⁺]=x :

[tex]\tt \sqrt{5.6.10^{-10}\times 0.41}=1.515.10^{-5}[/tex]

pH=-log[H₃O⁺]

[tex]\tt pH=5-log~1.515=4.82[/tex]

When elements bond together or when bonds of compounds are broken and form a new substance
A. Fireworks
B. Chemical Reaction
C. Chemical Change

D. Energy

Answers

The correct answer is C, chemical change.

Which of the following most likely causes the rate of a chemical reaction to increase?

Answers

Answer:

Adding heat to the reaction or increasing pressure

Explanation:

Increasing temperature or pressure will result in chemical reaction rates to speed up.

Sodium is a soft metal with a relatively low work function. Light corresponding to 476 kJmol−1 was shone on the sodium metal, and the electrons detected had a velocity of 9.57×105ms−1. What is the work function of sodium metal based on this data? The mass of an electron is 9.11×10−31kg.

Answers

Based on the data given, the work function of sodium metal is equal to [tex]7.91 \times 10^{-19}\;Joules[/tex].

Given the following data:

Mass of an electron = [tex]9.11\times10^{-31}\;kg[/tex].Photo electric work function = 476 kJ/mol.Velocity of electrons = [tex]9.57\times10^{5}\;m/s[/tex]

Avogadro constant = [tex]6.02 \times 10^{23}[/tex]

To determine the work function of sodium metal based on this data:

Mathematically, the photoelectric effect is given  by the formula:

[tex]K.E = hf - BE_i[/tex]

Where:

K.E represents the maximum kinetic energy of the ejected electron.f is photon frequency.h is Planck constant ([tex]6.626 \times 10^{-34}\;J.s[/tex]).[tex]BE_i[/tex] is the work function of the material.

However, since we were given the photo electric work function of light that was shone on the sodium metal, we would calculate the work function of sodium metal as follows:

[tex]\phi = \frac{Photo \;electric\; work \;function}{Avoadro's\;number}[/tex]

[tex]\phi = \frac{476 \times 10^3}{6.02 \times 10^{23}} \\\\\phi = 7.91 \times 10^{-19}\;Joules[/tex]

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If we combine the reaction of an acid protonating water and the reaction of its conjugate base deprotonating water, the net reaction after canceling common terms is:______

a. The acid-base reaction between the acid and its conjugate base.
b. The synthesis of a complex between the acid and its conjugate base.
c. The autoionization of water
d. None of the above

Answers

Answer:

C

Explanation:

The net reaction  after canceling common terms should be considered as the autoionization of water.

What is autoionization of water?

Since acids and bases should be react with each other, this shows that water could be react with itself. Here the sound should be stranged. Also, the water molecules should be exchanged the protons to the small extent.

hence, The net reaction  after canceling common terms should be considered as the autoionization of water.

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Which of the following is extrusive? A. Lava. B. Magma. C. Laccolith. D. Batholith.

Answers

Answer:

I think its C if I'm wrong plz forgive me

Answer:

the other answer is incorrect

Explanation:

What neutral element will have the electron configuration 1s22s22p63s23p1?

Select one:
a. aluminum
b. boron
c. carbon
d. silicon

Answers

Answer:

a. aluminum

Explanation:

Given electronic configuration:

       1s² 2s² 2p⁶ 3s² 3p¹  

The number of electrons can be determined from adding the powers or superscripts.

Since we are dealing with a neutral element, the number of electrons and protons are the same. So we can determine the atomic number which is the number of protons.

Number of electrons  = 2 + 2 + 6 + 2 + 1  = 13

The element with atomic number 13 is aluminum.

The given electronic configuration adds up to 13 which is the atomic number of aluminium.Thus, the correct option is A.

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. Aluminium has the given electronic configuration.

Thus, the correct option is A.

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a single covalent bond is made up of​

Answers

Answer:

In chemistry, a single bond is a chemical bond between two atoms involving two valence electrons. That is, the atoms share one pair of electrons where the bond forms. Therefore, a single bond is a type of covalent bond.

Explanation:

(copied from Google)

If I start with 0.0350 L of a 12.0 M hydrochloric acid solution, and dilute it with water to a new volume of 1.20 L, what is the new concentration?

Answers

Answer:

0.35 M

Explanation:

Using the formula; C1V1 = C2V2

Where;

C1 = concentration of initial solution

C2 = concentration of final solution

V1 = volume of initial solution

V2 = volume of final solution

Based on this question, I start with 0.0350 L of a 12.0 M hydrochloric acid solution, and dilute it with water to a new volume of 1.20 L. This means that:

C1 = 12.0 M, V1 = 0.0350 L, V2 = 1.20 L, C2 = ?

Hence, C1V1 = C2V2

12 × 0.0350 = C2 × 1.20

0.42 = 1.2C2

C2 = 0.42/1.2

C2 = 0.35 M

A procedure involving removal of the coronal portion of an exposed vital pulp is a

Answers

Answer:

ExplanaPulpotomy is a vital pulp therapy in which the coronal portion of the pulp is removed surgically and the remaining radicular pulp is preserved intact. Over the remaining radicular pulp tissue, a suitable material is placed which has the potential to protect the pulp from further insult and initiate healing and repairtion:

Answer:

preserve of the vitality of the remaining portion of the pulp within the root of the tooth. Also referred to as root canal therapy

Explanation:

show is a pedigree chart. the chart shows that sally is carrier for red-green color blindness​

Answers

Answer:

you cant post pictures on brainly answers.... can you?

Explanation:

Which are the products in the equation CH3SH + 4O2 → CO2 + SO2 +2H2O? Check all that apply. CH3SH O2 CO2 SO2 H2O

Answers

To calculate the atoms of an element in a given molecule, we need to multiply stoichiometry by the number that is written on the foot of that element. Therefore, the products are carbon dioxide, sulfur dioxide and water.

What is Balanced equation?

Balanced equation is the one in which the total number of atoms of a species on reactant side is equal to the total number of atoms on product side. The mass of the overall reaction should be conserved. There are so many types of chemical reaction reaction like combination reaction, displacement reaction.

The other characteristic of balanced equation is that physical state should be written with each compound or molecule on reactant and product side. Physical state should be written in brackets. s means solid, l means liquid, g means gas.

The balanced equation is

CH[tex]_3[/tex]SH + 4O[tex]_2[/tex] → CO[tex]_2[/tex] + SO[tex]_2[/tex] +2H[tex]_2[/tex]O

The products that are formed in the given reaction are carbon dioxide, sulfur dioxide and water.

Therefore, the products are carbon dioxide, sulfur dioxide and water.

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Which symbol in a chemical equation separates the reactants from the products?

Answers

Answer:

The arrow symbol in a chemical equation separates the reactants from products. A chemical reaction is process in which chemical changes leads to the formation of products from reactants.

Explanation:


Which is an advantage of using gymnosperms as decorative outdoor plants around homes and businesses?
Most of them do not grow very tall.
Most of them stay green all year.
All of them produce colorful flowers,
All of them have sharp needle-like leaves.

Answers

Answer:

i just took the test the correct answer is   "most of them stay green all year"

Explanation:

Answer:

its B :)

Explanation:

cuz im mr beast

What is the reason for the trend in Electron Affinity? Select all that apply.
A. number of protons in the nucleus
B. number of energy levels around the nucleus C. number of neutrons in the nucleus
D. larger atomic mass number
E. number of valence electrons.​

Answers

Answer:

i think it a and d

Explanation:

A and D hope this helped
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