2. Calculate the atomic mass of an element that has two isotopes, each with 50.00% abundance. One isotope has a mass of 63.00 amu and the other has a mass of 68.00 amu.

Answers

Answer 1

Answer:

The atomic mass of element is 65.5 amu.

Explanation:

Given data:

Abundance of X-63 = 50.000%

Atomic mass of  X-63 = 63.00 amu

Atomic mass of X-68 = 68.00 amu

Atomic mass of element = ?

Solution:

Abundance of X-68 = 100-50 = 50%

Average atomic mass = (abundance of 1st isotope × its atomic mass) +(abundance of 2nd isotope × its atomic mass)  / 100

Average atomic mass  = (50×63)+(50×68) /100

Average atomic mass =  3150 + 3400 / 100

Average atomic mass  = 6550 / 100

Average atomic mass = 65.5 amu.

The atomic mass of element is 65.5 amu.


Related Questions

What type of energy is stored in fuels such as gasoline and batteries

Answers

Answer:Chemical energy

Explanation:Chemical energy is energy stored in the bonds of atoms and molecules. Batteries, biomass, petroleum, natural gas, and coal are examples of chemical energy. Chemical energy is converted to thermal energy when people burn wood in a fireplace or burn gasoline in a car's engine.

The type of energy which  is stored in fuels such as gasoline and batteries is chemical energy.

What is chemical energy?

Energy which is stored in the chemical bonds of chemical compounds is called chemical energy.Chemical energy is released during the occurrence of chemical reaction.Reactions wherein energy is given out in the form of heat is called exothermic reactions.

Chemical energy can be converted to other forms of energy like electrical energy during the process of electrolysis and to thermal energy as in the case of thermal engines.

It can also be converted to kinetic energy during explosions . It is stored in batteries, coal, biomass, food, vehicle air bags,etc.

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What color of light has the wavelength 5.6 x 10 -7 meters

Answers

Answer:

49

Explanation:

i multiply 5.6 times 10 and mines 7

why are divergent boundaries are also called a constructive boudary

Answers

Answer: Divergent boundaries are where two of those plates are moving away from each other. They are called constructive plates because when they move apart, magma rises up in the gap- this forms volcanoes and eventually new crust.

Explanation:

a wavelength of 4.73 x 10-7 m, and a frequency of

Answers

Answer:

Frequency =0.634×10¹⁵ s⁻¹

Explanation:

Given data:

Wavelength = 4.73×10⁻⁷ m

Frequency = ?

Solution:

Formula:

speed of light = wavelength× frequency

speed of light = 3×10⁸ m/s

Now we will put the values in formula.

3×10⁸ m/s = 4.73×10⁻⁷ m × frequency

Frequency = 3×10⁸ m/s /4.73×10⁻⁷ m

Frequency =0.634×10¹⁵ s⁻¹

s⁻¹ = Hz

Frequency =0.634×10¹⁵ Hz

A balance reads an object A to be 45.1 kg. The balance reads another object B to be 33.46 kg. What is the total weight of both objects

Answers

Answer:

The total weight of both object is 78.56 kg.

Explanation:

Given data:

Mass of object A = 45.1 kg

Mass of object B = 33.46 kg

Total weight of object = ?

Solution:

Total weight of both subject must be the sum of weight of object A and B.

Total weight of objects = weight of object A + weight of object B

Now we will put the values of mass of object A and B.

Total weight of objects = 45.1 kg + 33.46 kg

Total weight of objects =78.56 kg

Thus the total weight of both object is 78.56 kg.

1) Ammonium cyanate, NH4CNO, in aqueous solution isomerizes gradually producing urea, H2NCONH2, according to the reaction

NH4CNO -> H2NCONH2
A solution was prepared by dissolving 22.9 g of ammonium cyanate in water to a volume of 1.0 liter. The evolution of the reaction, at 300k, was followed by the urea mass formed:

(a) Determine the order of the reaction

(b) Calculate the half-life of ammonium cyanate for the initial conditions of the problem

Ammonium cyanate/urea molar mass= 60g/mol

2) For the reaction
Ni(NCS)^+ + NCS Ni (NCS)2

a) Determine the Ea in direct and reverse direction using an Arrhenius graph.
b) Make, also, a qualitative diagram of energy vs. reaction coordinate indicating the values of the energies for the transposition of the barrier of direct and inverse reaction


3) Among the possible destinations of NO2 in atmospheric chemistry is the decomposition to form NO and O2. This reaction was studied at 370 C and the results obtained were as follows

based on this data, determine the speed constant K

Answers

Answer:

1(a) Second order

1(b) 44.0 minutes

2(a) Ea, forward = 85.6 kJ/mol

Ea, reverse = 60.1 kJ/mol

3) k = 9.47 M⁻¹s⁻¹

Explanation:

1(a) We are given mass of product vs time.  We need to find the concentration of reactant.

For example, at t = 0 min, there is 0 g of product.  Therefore, there is 22.9 g − 0 g = 22.9 g of reactant.  The molar mass is 60 g/mol, so there is (22.9 g) / (60 mol/g) = 0.382 mol.  The volume is 1.0 L, so the concentration is (0.382 mol) / (1.0 L) = 0.382 M.

Next, we'll graph [A] vs time, ln[A] vs time, and 1/[A] vs time.

From the graphs, we can see that 1/[A] is linear.  That means the reaction is second order.

1(b) The slope of the line is equal to the rate constant k.

k = 0.0596 M⁻¹min⁻¹

The half life is:

t = 1/(k [A₀])

where [A₀] is the initial concentration of reactant.

t = 1 / (0.0596 M⁻¹min⁻¹ × 0.382 M)

t = 44.0 min

(Notice the mass of product approximately doubles from t = 20 min to t = 45 min.  This confirms that the half life is about 44 minutes.)

2(a) To make an Arrhenius graph, we need to graph ln(k) vs 1/T, where T is temperature in Kelvin.  We'll make two graphs, one for ka (the forward reaction) and one for kb (the reverse reaction).

The slope of each line is -Eₐ/R, where R is the gas constant.  For the forward reaction:

Eₐ = -8.314 × -10300 = 85,600 J/mol = 85.6 kJ/mol

For the reverse reaction:

Eₐ = -8.314 × -7227.6 = 60,100 J/mol = 60.1 kJ/mol

2(b) Make a graph showing the energy changes as the reaction goes from the reactants to the products.  The difference between the reactants and the highest point is the forward activation energy.  The difference between the products and the highest point is the reverse activation energy.

3) Like problem #1, we're going to graph [A], ln[A], and 1/[A] vs time.

Once again, 1/[A] vs t is linear, so this is a second order reaction.

The rate constant is the slope of this line, so k = 9.47 M⁻¹s⁻¹.

6) Which of these elements is a metal?
E) C
D) N
A) O
C) Ne
B) Ca

Answers

Answer:

Ca

Explanation:

It is on the left side of the periodic table where metals are located.

Answer:

Ca

Explanation:

In a decomposition reaction, NaCl might form which of the following?

A. H20

B. FeS

C. Na and Cl

D. All of the above

Answers

Answer:

THE ANSWER IS C

Explanation:

In a decomposition chemical change, NaCl might form sodium and chlorine , hence option C is correct.

What is a chemical change?

Chemical changes are defined as changes which occur when a substance combines with another substance to form a new substance.Alternatively, when a substance breaks down or decomposes to give new substances it is also considered to be a chemical change.

There are several characteristics of chemical changes like change in color, change in state , change in odor and change in composition . During chemical change there is also formation of precipitate an insoluble mass of substance or even evolution of gases.

There are three types of chemical changes:

1) inorganic changes

2)organic changes

3) biochemical changes

During chemical changes atoms are rearranged and changes are accompanied by an energy change as new substances are formed.

Learn more about chemical change,here:

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whai is the maining of science?

Answers

Answer:

the intellectual and practical activity encompassing the systematic study of the structure and behaviour of the physical and natural world through observation and experiment.

Explanation:

If it takes a Sonar echo 8 seconds to reach the bottom of the ocean and return and we know that the speed of sound is 1500 meters per second, how far away is the bottom of the ocean?:


A) 4000 meters

B) 8000 meters

C) 6000 meters

D) 1200 meters

Answers

Answer:

C) 6000 meters.

Explanation:

Hello.

In this case, since the speed is computed as the distance divided by the time to attain such displacement:

[tex]s=\frac{d}{t}[/tex]

Knowing that the speed is 1500 m/s and the required time is 4 s because is the half of the described travel, the distance is then:

[tex]d=s*t\\\\d=1500m/s*4s\\\\d=6000m[/tex]

Therefore, the answer is C) 6000 meters.

Best regards.

Answer:

600 meters i took test ;)

Explanation:

How are the molecules in a substance behaving if a great deal of thermal energy has transferred away from it through conduction?

Answers

Answer:

the molecules would be slowing down

Explanation:

Answer:

they'd slow down durr

Explanation:

What is the last sequence for Silver

4d7
4d7

4d9
4d9

4p2
4p2

3d7

Answers

Answer:

4d₉

Explanation:

Silver is atomic number 47, Ag. So, count to 47 in orbitals:

1s₂ 2s₂ 2p₆ 3s₂ 3p₆ 4s₂ 3d₁₀ 4p₆ 5s₂ 4d₉

2 + 2 + 6 + 2 + 6 + 2 + 10 + 6 + 2 + 9 = 47

This sequence ends in 4d₉, therefore it is the last sequence.

What is necessary to release the chemical energy from food: explosion water sunlight oxygen

Answers

Answer:

Oxygen

Explanation:

Photosynthesis releases oxygen into the atmosphere and cellular respiration uses that oxygen to release energy from food.

what I do when I need to eat

Answers

You eat food when you need to eat!!!

A star produces energy by:
A. expanding and contracting its magnetic field.
B. creating sunspots and releasing coronal ejections.
C. combining two atoms to form a larger atom, releasing energy.
D. splitting atoms apart, releasing energy in the form of photons.

Answers

Answer : C

Explanation:

a star produces energy by combining two atoms into one creates a powerful burst of energy

Descibe how electronegativity and molecular shape determine the polarity of a molecule. Then describe why chemists consider relative electronegativity values and not absolute electronegativity values when determining the polarity of a bond. Also explain how a molecule with polar bonds can be non-polar overall.​

Answers

Answer:

See explanation

Explanation:

Electronegativity is an idea put forward by Linus Pauling to explain the fact that in a molecule, one atom may attract the shared electrons of the bond closer to itself than the other.

Hence electronegativity is defined as the power of an atom in a molecule to attract electrons to itself.

Pauling originally described electronegativity as a relative quantity. It depends on the electronegativities of the atoms in the molecule. However, some methods have sought to measure the absolute electronegativity of a free atom.

A bond is polar when the atoms that make up the bond have a significant difference between the atoms of the molecule.

However, a molecule may possess polar bonds but may not have an overall dipole moment owing to the shape of the molecule.

For instance, CCl4 has four polar C-Cl bonds but the overall molecule is non polar because due to the fact that the molecule is tetrahedral in shape and highly symmetrical hence the individual dipoles cancel out.

Which atom has only one pair of electrons in its outermost energy level?
a. Boron b. carbon c. nitrogen d. oxygen

Answers

Answer:

i belive A, i cold be wrong tho, pls tell me if im right if you fully find out

ght. Explanation:

What are the uses for carbon?

Answers

It’s used as fuel:) please say Thank you

What is the most strongest material bedrock Obsidian or diamond​

Answers

The answer is Obsidian.

write a short note on the function of the Amino acid in human body.​

Answers

Answer:

Hello

Amino acids function as the building blocks of proteins. Proteins catalyze the vast majority of chemical reactions that occur in the cell. They provide many of the structural elements of a cell, and they help to bind cells together into tissues.

Hope it helps you...

Which of the following is an example of an endothermic reaction?
!!! thank u!!

Answers

Answer:

Combustion

Explanation:

Which of the following has thermal energy?

A. Both a piece of metal that feels hot and a piece of metal that feels cold.
B. A piece of metal that feels hot but not a piece of metal that feels cold
C. A piece of metal that feels cold but not a piece of metal that feels hot
D. Neither a piece of metal that feels hot nor a piece of metal that feels cold

Answers

It’s c because I took the test

what energy transformations does microwave have

Answers

Answer:

radiant energy

Explanation:

microwaves convert electrical energy into radiant energy

what is gravity and weight please answer

Answers

Weight is the force of gravity on an object. Weight depends on the strength of the gravitational field the object is in and the mass of the object. ... Mass is constant anywhere in the universe, whereas weight depends on the gravity where the object is present (Earth, the moon, Jupiter, etc.).

________ is a trend making computers ubiquitous?

Answers

Answer:

Pervasive computing, also called ubiquitous computing, is the growing trend of embedding computational capability (generally in the form of microprocessors) into everyday objects to make them effectively communicate and perform useful tasks in a way that minimizes the end user's need to interact with computers as ...

Explanation:

Easy Question. Will mark brainliest

Carbon combines with oxygen to form two compounds, carbon monoxide and carbon dioxide. Based on the law of multiple proportions, describe how the proportions of oxygen in the two compounds relate to each other.

Answers

Answer:

Their components

Explanation:

It's simple enough, the components in carbon dioxide and carbon monoxide both have at least one carbon and one oxygen atom. However, they differ because their amount in the molecules is different, and that is because of their covalent bonds. Carbon dioxide has to double electron bonds while carbon monoxide has a rare triple electron bond.

sxty-D

1. What fraction of the elements on the periodic table are metals?

Answers

Answer:

80%

Explanation:

What do you suppose is the reason and what do you need to do.

Answers

Answer:

You have to add many things

Explanation:

for example u can add why and how also what ur point is

The element Aluminium (AI) Is

Answers

Answer:

a metal which is found in 13 group and 3 period of periodic table

What my favorite food only question for JungKookLuver and jguzman577! Or if u answer I report you!

Answers

Answer: Pizza

Explanation: Pizza

Answer:

Shiver me timbers its pizza

Explanation:

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