Consider an element X that has two naturally occurring isotopes with the following percent abundances: the first isotope has a mass number of 84.912 and is 72.17% abundant; the second isotope has a mass number of 86.909 and is 27.83% abundant. What is the average atomic mass for element X?

Answer:

Ca

Explanation:

Answer:  Chemical symbols are used to represent atoms and elements.  A compound consists of atoms of two or more elements combined in a small, whole-number ratio. Atoms of each of its elements are always present in the same ratio

Explanation:

Answer:

m = 671 grams

Explanation:

Given that,

No of moles, n = 4.9

Molar mass of Barium, M = 137 g

Mass divided by molar mass is equal to no of moles. It can be given by the formula as follows :

[tex]n=\dfrac{m}{M}\\\\m=n\times M\\\\m=4.9\times 137\\\\m=671.3\ g[/tex]

or

m = 671 grams

So, the total mass of the sample of Barium is 671 grams.

Answer:

The first 3

Explanation:

Eukaryotic cells are usually multicellular, contain a true nucleus, and contain membrane-bound organelles. Hence, options A, B and C are correct.

The eukaryotic cell has a nuclear membrane that surrounds the nucleus, in which the well-defined chromosomes (bodies containing the hereditary material) are located.

Eukaryotic cells are usually multicellular, contain a true nucleus, and contain membrane-bound organelles.

Hence, options A, B and C are correct.

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Answer:

Balanced equations are those whose coefficients result in equal numbers of atoms for each element in the reactants and products.

Answer:

An element is a single atom by itself found on the periodic table. A compound  is made when two or more elements chemically bond together. An example of an element is hydrogen. (H) An example of a compound is [tex]H_{2} O[/tex].

Explanation:

explained above

Answer:

Normally, it explains that matter cannot be created or destroyed. It demonstrates different chemical reactions that help show the different transformations of the matter but will never destroy it or create it.

Answer:

2 elements

Explanation:

Octane is composed of carbon and hydrogen atoms.

Answer:

The average?

Explanation:

Answer:

V = 3.75 cm³

Explanation:

Density = Mass / Volume

Step 1: Define variables

D = 8.00 g/cm³

M = 30.0 g

V = unknown

Step 2: Substitute and Evaluate for V

8.00 g/cm³ = 30 g/ V

V = 15/4 cm³

V = 3.75 cm³

Answer:

either a car or a rock

Explanation:

because the rock can weigh more than the car , and vice-versa with the car weighing more than the rock

Answer:Mole, also spelled mol, in chemistry, a standard scientific unit for measuring large quantities of very small entities such as atoms, molecules, or other specified particles.

Explanation:

Answer:

it doesnt even give you enough information for you to answer it

Explanation:

Answer:

it doesnt even give you enough information for you to answer it

Explanation:

Answer:

Detail is given below.

Explanation:

Atomic radius  trend along period:

As we move from left to right across the periodic table the number of valance electrons increases. The atomic size tend to decrease in same period of periodic table because the electrons are added with in the same shell. When the electron are added, at the same time protons are also added in the nucleus. The positive charge is going to increase and this charge is greater in effect than the charge of electrons. This effect lead to the greater nuclear attraction. The electrons are pull towards the nucleus and valance shell get closer to the nucleus. As a result of this greater nuclear attraction atomic radius decreases and ionization energy increases because it is very difficult to remove the electron from atom and more energy is required.

we can see in picture A there is one positive charge and force of attraction is 2.30×10⁻⁸ N

In picture D there are 2 positive charge and force of attraction is 4.60×10⁻⁸ N

So by increasing the positive charge force of attraction also increases.

In F we can see there is more positive charge thus force of attraction is also greater.

Answer:

Electron Configurations - Solutions

Note: The electron configurations in this worksheet assume that lanthanum (La)

is the first element in the 4f block and that actinium (Ac) is the first element in the

5f block. If your periodic table doesn’t agree with this, your answers for elements

near the f-orbitals may be slightly different.

1) sodium 1s2

2s2

2p6

3s1

2) iron 1s2

2s2

2p6

3s2

3p6

4s2

3d6

3) bromine 1s2

2s2

2p6

3s2

3p6

4s2

3d104p5

4) barium 1s2

2s2

2p6

3s2

3p6

4s2

3d104p6

5s2

4d105p6

6s2

5) neptunium 1s2

2s2

2p6

3s2

3p6

4s2

3d104p6

5s2

4d105p6

6s2

4f145d106p6

7s2

5f5

6) cobalt [Ar] 4s2

3d7

7) silver [Kr] 5s2

4d9

8) tellurium [Kr] 5s2

4d105p4

9) radium [Rn] 7s2

10) lawrencium [Rn] 7s2

5f146d1

11) 1s2

2s2

2p6

3s2

3p4

sulfur

12) 1s2

2s2

2p6

3s2

3p6

4s2

3d104p6

5s1

rubidium

13) [Kr] 5s2

4d105p3

antimony

14) [Xe] 6s2

4f145d6

osmium

15) [Rn] 7s2

5f11 einsteinium

16) 1s2

2s2

2p6

3s2

3p6

4s2

4d104p5 not valid (take a look at “4d”)

17) 1s2

2s2

2p6

3s3

3d5

not valid (3p comes after 3s)

18) [Ra] 7s2

5f8

not valid (radium isn’t a noble gas)

19) [Kr] 5s2

4d105p5 valid

20) [Xe] not valid (an element can’t be its own electron configuration)

Answer:

The Stomata

Explanation:

The Stomata is found in the leaves of plants and controls their gas exchange with the environment around them.

Answer:

Aluminum isn't found pure naturally, but its found mixed with other minerals in the earth. It's used to make cans, foil, kitchen utensils, window frames and even deodorant

Explanation:

Answer:

heat of fusion

Explanation:

heat of fusion is melting which requires more heat energy than heat of vaporization

Answer:

B

Explanation:

The gravity accelleration values are the same for both planets.

B: Mercury and Mars have the same gravitational force.

You can see at the chart, it shows

Gravity: Mercury          Mars

            3.7 m/s2         3.7 m/2

Answer:

false false false false

Answer:

4.75 or 4.8

Explanation:

density = mass / volume

57 / 12 = 4.75

from here you can leave it as is or round up.

hope this helps!!

Answer:

[tex]\boxed {\tt Number \ and \ unit}[/tex]

Explanation:

The two requirements for a measurement are a number and a unit.

For example, here is a measurement:

38.6 cm

The number is 38.6 and the unit is cm, or centimeters.

Therefore, both number and unit are correct.

Answer:

Several heavy elements, such as uranium, thorium, and plutonium, undergo both spontaneous fission, a form of radioactive decay and induced fission, a form of nuclear reaction.

Explanation:

Rutherford’s laboratory showed that when alpha particles are fired into gas atoms, a few are violently deflected, which implies a dense, positively charged central region containing most of the atomic mass.

Answer:

A prefix

Explanation:

you're welcome

The covalent molecules named as,

So, option B is correct one.

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Answer:

730 mL which is .73 L

Explanation: