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2 years ago

4. Write the electronic configuration of first 20 elements in the periodic table.

Chemistry

1 answer:

DIA [1.3K]2 years ago

7 0

Answer:

Name Atomic Number Electron Configuration Period 1 Hydrogen 1 1s1 Helium 2 1s2 Period 2 Lithium 3 1s2 2s1 Beryllium 4 1s2 2s2 Boron 5 1s2 2s22p1 Carbon 6 1s2 2s22p2 Nitrogen 7 1s2 2s22p3 Oxygen 8 1s2 2s22p4 Fluorine 9 1s2 2s22p5 Neon 10 1s2 2s22p6 Period 3 Sodium 11 1s2 2s22p63s1 Magnesium 12 1s2 2s22p63s2 Aluminum 13

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The molar percent of a in stream 3 is _________ mol% a in stream 1.

vredina [299]

From the problem description you've given, I can't give an exact answer without a context. However, I found a similar problem with an illustration. Supposing this is the problem, we can set a mole balance:

n₁ = n₂ + n₃

Since n₃ is just part of n₁, it will always be less than n₁ because n₁ constitutes 100% mol A. Thus, the answer is letter C.

4 0

3 years ago

The average density of a carbon-fiber-epoxy composite is 1.615 g/cm3. the density of the epoxy resin is 1.21 g/cm3 and that of t

ra1l [238]

The composite material is composed of carbon fiber and epoxy resins. Now, density is an intensive unit. So, to approach this problem, let's assume there is 1 gram of composite material. Thus, mass carbon + mass epoxy = 1 g.

Volume of composite material = 1 g / 1.615 g/cm³ = 0.619 cm³
Volume of carbon fibers = x g / 1.74 g/cm³
Volume of epoxy resin = (1 - x) g / 1.21 g/cm³

a.) V of composite = V of carbon fibers + V of epoxy resin
0.619 = x/1.74 + (1-x)/1.21
Solve for x,
x = 0.824 g carbon fibers
1-x = 0.176 g epoxy resins

Vol % of carbon fibers = [(0.824/1.74) ÷ 0.619]*100 = 76.5%

b.) Weight % of epoxy = 0.176 g epoxy/1 g composite * 100 = 17.6%
Weight % of carbon fibers = 0.824 g carbon/1 g composite * 100 = 82.4%

4 0

2 years ago

If water (p=998 kg/m3, u = 10-3 Pa.s) flows through a 50 m Pa.s) determine the velocity of carbon tetrac me the velocity of carb

babymother [125]

Explanation:

As it is given that both have same dynamic characteristics.

Therefore, $Re_{water}$ = $Re_{CCl_{4}}$

$\frac{\rho_{water} \times \nu_{water} \times D_{water}}{\mu_{water}}$ = $\frac{\rho_{CCl_{4}} \times \nu_{CCl_{4}} \times D_{CCl_{4}}}{\mu_{CCl_{4}}}$

Hence, putting the given values into the above formula as follows.

$\frac{998 kg/m^{3} \times 2 m/s \times 50 mm}{10^{-3}Pa.s}$ = $\frac{1590 kg/m^{3}} \times \nu_{CCl_{4}} \times 60 mm}{0.958 \times 10^{-3}}$

$\nu_{CCl_{4}}$ = 1.002 m/s

Thus, we can conclude that the velocity of carbon tetrachloride in the given conditions is 1.002 m/s.

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2 years ago

Which of the following best describe the chronological way of specimen preparation?

nata0808 [166]

Answer:

There are many reasons to examine human cells and tissues under the microscope. Medical and biological research is underpinned by knowledge of the normal structure and function of cells and tissues and the organs and structures that they make up. In the normal healthy state, the cells and other tissue elements are arranged in regular, recognizable patterns. Changes induced by a wide range of chemical and physical influences are reflected by alterations in the structure at a microscopic level, and many diseases are characterized by typical structural and chemical abnormalities that differ from the normal state. Identifying these changes and linking them to particular diseases is the basis of histopathology and cytopathology, important specializations of modern medicine. Microscopy plays an important part in haematology (the study of blood), microbiology (the study of microorganisms including parasites and viruses), and more broadly in the areas of biology, zoology, and botany. In all these disciplines, specimens are examined under a microscope.

hope it helps 

8 0

1 year ago

Read 2 more answers

4) Select all the terms according to the subatomic particle of an electron.

Paladinen [302]

Answer:I think it’s B

Explanation:

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2 years ago