I have science and i have a question that says : an element is a (valuable, pure , rare) substance that is not chemically combined with any other elements

Answers

Answer 1

Answer:

It’s true ( pure).

Explanation:

An element is defined as a pure substance that is not chemically combined with any other elements. An element comprises of mainly the sane type of atoms.

While a compound is a substance that consists of two or more elements which are chemically combined together. This is the main difference between an element and a compound.


Related Questions

Match the following parts of the earth with the correct definition: Definitions: 1. Solid, outer layer of the earth 2. Layer between the crust and the core 3. Semi-liquid region directly beneath the crust 4. Made of iron and nickel 5. The water covering the surface of the earth
Words: Mantle, Core, Crust, Hydrosphere, Asthenosphere

Answers

Answer:

1) crust

2)mantle

3) asthenosphere

4)core

5) hydrosphere

Explanation:

Hope this helps, Let me know if i am wrong( i dont think i am but, yeah...), OH! and GOOD LUCK!  :D ;P.

Determine the number of protons, neutrons, and electrons for a neutral potassium-41 isotope.

Answers



Atomic number is equal to the number of electrons in a neutral atom. ... Niobium has an atomic number of 41. ... Determine the number of protons, electrons, and neutrons for each isotope described ... Potassium-41. 19

which of these processes are chemical reaction

Answers

Answer:

I don't think u finished the question -

(2 words) if compose means to put together then decompose means to what? 9 letters!​

Answers

take apart (I’m adding this extra text or else it won’t let me send)

omg can somebody please help me with these 2 questions

Answers

Answer: Q4=1 Q5=2

Explanation:

Best of luck.

Answer:

4. '4' "pathogens can interfere with normal life functions."

5. '2' "synthesizing antibodies that mark these organisms to be destroyed."

Explanation:

What do I write? Please hurry

Answers

Answer:

Plants wilt when the turgor turns to zero. From diminished water in cells. The rate of water being lost is greater then the water being absorbed.

Something like this. NOT EXACTLY THIS this is just an example.

I didn't know anything about this topic but I looked it up. For the other words I would look up the other words and see what they have to do with plants withering.

What is a characteristic that can be observed or measured without changing the chemical makeup of a substance? *
a.chemical property
b.physical property
c.chemical change
d.physical change

Answers

The correct answer is B

Which ocean borders Africa on the western coast?
pls answer for 20 coiins

Answers

Answer:

indian ocean

Explanation:

Sort the characteristics based on whether they describe a dog, a computer, or both.
has internal
organization
has living
cells
uses energy
produces
offspring
lacks genetic
material

Answers

Answer:

both have internal organization dog only has living cells both use energy dogs only produce offspring computers only lack genetic material

1-Convert the following to moles:
1.5 X 10^23 atoms of Carbon

Answers

Answer:

0.249087

Explanation:

1.5 x 10^23 atoms x 1 mole / 6. 022 x 10^23 atoms

= 0.249087

5 grams of KClO3 is dissolved in 100 g of water at 30 °C. How
many more grams of Kcloz Should be added in order to create a
saturated solution?
A 5 grams
B
10 grams
С
15 grams
D
1 gram

Answers

Answer:

15 grams

Explanation:

Which of these is NOT a layer of the skin?

Answers

I need the options to choose from

Answer:

Penis EPISODE ONE!!

NEW ADVENTURES

Explanation: MAKE SURE TO LIKE AND SUB!!

compare and contrast the similarities and differences between passive and active transport

Answers

Both involve ion movement. Both use ion channels to move ions across the cell membrane, in or out of the cell. ... Passive Transport (or Diffusion) moves ions from high concentration to low, using no metabolic energy. Active Transport moves ions from low concentration to high, using metabolic energy in the form of ATP.

Global warming is mainly due to

CFC's

Ozone Holes
Nitric and sulfuric acids

Greenhouse gases

Answers

Answer:

Explanation:

Glaciers are melting, sea levels are rising, cloud forests are dying, and wildlife is scrambling to keep pace. It has become clear that humans have caused most of the past century's warming by releasing heat-trapping gases as we power our modern lives. Called greenhouse gases, their levels are higher now than at any time in the last 800,000 years.

We often call the result global warming, but it is causing a set of changes to the Earth's climate, or long-term weather patterns, that varies from place to place. While many people think of global warming and climate change as synonyms, scientists use “climate change” when describing the complex shifts now affecting our planet’s weather and climate systems—in part because some areas actually get cooler in the short term.

Climate change encompasses not only rising average temperatures but also extreme weather events, shifting wildlife populations and habitats, rising seas, and a range of other impacts. All of those changes are emerging as humans continue to add heat-trapping greenhouse gases to the atmosphere, changing the rhythms of climate that all living things have come to rely on.

What will we do—what can we do—to slow this human-caused warming? How will we cope with the changes we've already set into motion? While we struggle to figure it all out, the fate of the Earth as we know it—coasts, forests, farms, and snow-capped mountains—hangs in the balance.

It is mainly due to Greenhouse Gases

N yogurt de 125 g muestra en su etiqueta el contenido de algunas de sus sustancias nutricionales:¿Cuál es la composición en tanto porciento en masa de cada una de las sustancias? Composición Sustancia Masa Proteínas 5,5 g Azúcares 5,0 g Sodio 0,06 g Potasio 0,15 g

Answers

Answer:

Sustancia  Masa (g)  Composición (% m/m)

Proteínas      5,5                  4,4

Azúcares      5,0                  4,0

Sodio            0,06               0,048

Potasio         0,15                 0,12

                         

Explanation:

Para calcular la composición porcentual en masa de las sustancias debemos usar la siguiente ecuación:

[tex] \%_{m/m} = \frac{m_{s}}{m_{sol}} \times 100 [/tex]

En donde:

[tex]m_{s}[/tex] es la masa de la sustancia

[tex]m_{sol}[/tex] es la masa del yogurt = 125 g

Para las proteínas:

[tex] \%_{m/m} = \frac{m_{s}}{m_{sol}} \times 100 = \frac{5,5 g}{125 g} \times 100 = 4,4 \% [/tex]

Para los azúcares:

[tex] \%_{m/m} = \frac{5,0 g}{125 g} \times 100 = 4,0 \% [/tex]

Para el sodio:

[tex] \%_{m/m} = \frac{0,06 g}{125 g} \times 100 = 0,048 \% [/tex]

Para el potasio:

[tex] \%_{m/m} = \frac{0,15 g}{125 g} \times 100 = 0,12 \% [/tex]

Espero que te sea de utilidad!    


lonic compounds can conduct electricity in

Answers

Ionic compounds can conduct electricity in liquid. Because there ions are free to move anywhere

Answer:

Ionic compounds conduct electricity when molten (liquid) or in aqueous solution (dissolved in water), because their ions are free to move from place to place. Ionic compounds cannot conduct electricity when solid, as their ions are held in fixed positions and cannot move

Explanation:

In the titration of acetic acid, CH3COOH, a 0.20 M solution of NaOH is used. A volume of 15.00 mL of CH3COOH solution is
titrated. If it takes a total of 24.55 mL of NaOH solution to reach the equivalence point, what is the molar concentration of the
CH3COOH solution?

Answers

Answer:

naci

Explanation:

The molar concentration of the CH₃COOH soluttion is 0.33 M

We'll begin by writing the balanced equation for the reaction. This is given below:

CH₃COOH + NaOH —>CH₃COONa + H₂O

From the balanced equation above,

The mole ratio of the acid, CH₃COOH (nA) = 1

The mole ratio of the base, NaOH (nB) = 1

From the question given above, the following data were obtained:

Volume of acid, CH₃COOH (Va) = 15 mL

Molarity of base, NaOH (Mb) = 0.2 M

Volume of base, NaOH (Vb) = 24.55 mL

Molarity of acid, CH₃COOH (Ma) =?

MaVa / MbVb = nA/nB

(Ma × 15) / (0.2 × 24.55) = 1

(Ma × 15) / 4.91 = 1

Cross multiply

Ma × 15 = 4.91

Divide both side by 15

Ma = 4.91 / 15

Ma = 0.33 M

Therefore, the molar concentration of the acid, CH₃COOH is 0.33 M

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Why should we never change a symbol in chemistry?

Answers

Answer:

Chemical symbols are used to standardize the 'language of chemistry' and to identify elements and atoms in a chemical formula easily. Chemical symbols consist of one or two letters, most often derived from the name of the element.

Explanation:

please help me will mark brainly

Answers

1. Physical
2. D
3. It’s either A or D but I think it’s A
4. C
5. A
6. D
7. A
8. B
9. I couldn’t see the question for it
10. A
11. D
12. D
13. B

What element is represented by each electron
configuration?
A. 1s 2s22p5
B. [Ar]4s
C. [Xe]6s24f
D. [Kr]5s4d105p+
E. [Rn]7s25f13
F. 1s 2s 2p 3s 3p 4s3d104p

Answers

Answer:

F.1s 2s 2p 3s 3p 4s3d104p

The element in the first configuration is F and the element in the second option is calcium Ca. The configuration in option c is of cerium Ce and it is cadmium in option D. The configuration in E is mendelevium and F is zinc.

What is electronic configuration?

An electronic configuration represents the filling of electrons in various energy level. Electrons fill from the lowest energy levels to the highest energy level.

The first configuration have a total of 9 electrons. The 9th element is fluorine. The second configuration given is of 20 electrons. That is 18 electrons of argon plus 2 electrons in 4s. The 20th element is calcium.

The third configuration have 58 electrons and the element is cerium Ce. The configuration given in option D is of cadmium with 48 electrons and that in option E is mendelevium with 101 electrons.

In the last option, the configuration contain a total of 30 electrons. 3o th element in periodic table is zinc, Zn.

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hi pls help me I don't get it ​

Answers

Answer:

It's most probably

A non metal

Which of the following is a inert gas?
oxygen
chlorine
nitrogen
aragon​

Answers

Answer:

argon is an inert gas

Explanation:

an inert gas is when a chemical helium, xenon, neon, krypton, radon are also inert gases

which atom in each pair has the larger atomic radius?
li or k
ca or ni
ga or b
o or c
cl or br
be or ba
si or s
fe or au

Answers

Answer:

1. Potassium, K.

2. Calcium, Ca.

3. Gallium, Ga.

4. Carbon, C.

5. Bromine, Br.

6. Barium, Ba.

7. Silicon, Si.

8. Gold, Au.

Explanation:

Atomic radius can be defined as a measure of the size (distance) of the atom of a chemical element such as hydrogen, oxygen, carbon, nitrogen etc, typically from the nucleus to the valence electrons. The atomic radius of a chemical element decreases across the periodic table, typically from alkali metals (group one elements such as hydrogen, lithium and sodium) to noble gases (group eight elements such as argon, helium and neon). Also, the atomic radius of a chemical element increases down each group of the periodic table, typically from top to bottom (column).

Additionally, the unit of measurement of the atomic radius of chemical elements is picometers (1 pm = 10 - 12 m).

1. Li or K: the atomic radius of lithium is 167 pm while that of potassium is 243 pm.

2. Ca or Ni: the atomic radius of calcium is 194 pm while that of nickel is 149 pm.

3. Ga or B: the atomic radius of gallium is 136 pm while that of boron is 87 pm.

4. O or C: the atomic radius of oxygen is 48 pm while that of carbon is 67 pm.

5. Cl or Br: the atomic radius of chlorine is 79 pm while that of bromine is 94 pm.

6. Be or Ba: the atomic radius of berryllium is 112 pm while that of barium is 253 pm.

7. Si or S: the atomic radius of silicon is 111 pm while that of sulphur is 88 pm.

8. Fe or Au: the atomic radius of iron is 156 pm while that of gold is 174 pm.

The atoms in each pair which has the larger atomic radius is;

Potassium, K.

Calcium, Ca.

Gallium, Ga.

Carbon, C.

Bromine, Br.

Barium, Ba.

Silicon, Si.

Gold, Au.

Definition:

Atomic radius is simply the distance from the centre of the nucleus to the outermost shell containing electrons.

In other words, the atomic radius is the distance from the center of the nucleus to the point up to which the electron cloud density is maximum.

Trend:

The atomic radius of atoms generally decreases from left to right across a period. The atomic radius of atoms generally increases from top to bottom within a group.

It is on this basis that atoms with the larger atomic radius are determined

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Please help due in 5 min. I need this to be done or my grade will drop from a 96 to a 32.
Calculate the energy and frequency of red light having a wavelength of 6.55 x 10^-5 cm.

Answers

Answer:

E = 3.035× 10-¹⁹J = 1.9eV

f = 4.58 × 10¹⁴Hz

Explanation:

wavelength = 6.55 × 10-⁷m

c = 3 × 10⁸m/s

f = ?

E = ?

a) f = c/wavelength

f = 3 × 10⁸/6.55 × 10-⁷

f = 4.58 × 10¹⁴Hz

b) E = hc/wavelength

E = 6.626×10-³⁴ × 3 × 10⁸/ 6.55 × 10-⁷

E = 3.035 × 10-¹⁹J

1ev = 1.6 × 10-¹⁹J

Therefore E = 3.035/1.6 = 1.9eV

Explanation:

speed of light = wavelength * frequency

frequency =speed of light/wavelength

Let frequency = F

Speed of light = 3.0 *10^8

wavelength = 6.55 * 10^-5 cm = 6.55 * 10^-7m

Therefore F= 3.0 *10^8m/s *6.55 * 10^-7m

F = 196.5Hz

Energy = Planck's constant * frequency

Let energy be E

Planck's constant = 6.63 * 10^-34Joule/ seconds

E = 6.63 * 10^-34 * 196.5Hz

E=1.3027 * 10^-31 J

A special layer of dermal cells are found on the top side of leaves. What level of organization would it belong to

Answers

Answer:

Tissue level of organization

Explanation:

The various levels of the organization of life are as follows:

Cells: a cell is the basic unit of ife

Tissues; A tissue is a group of cells with a common origin. performing similar functions.

Organ: an organ is a group of tissues with varied or similar function that work together to perform a specific function.

System: a system is a group of different organs that work together in the body to perform a specific function.

Since, the leaf is an organ in the plant that performs the function of photosynthesis, the group of dermal cells found on the leaf are in the tissue level of organization, they perform the function of protection for the leaf.

In which option do all three particles have the same electronic configuration?

And the same number of neutrons? (7N , 8O , 9F ,10Ne , 12Mg)

(a) 15N3- 16O2- 19F-

(b) 18O2- 19F- 20Ne

(C) 19F- 20Ne 23Na+

(d) 22Ne 23Na 24Mg2+

Answers

b. ₈¹⁸O²⁻ , ₉¹⁹F⁻ , ₁₀²⁰Ne

Further explanation

The Atomic Number (Z) indicates the number of protons and electrons in an atom of an element.

Atomic number = number of protons = number of electrons ⇒ neutral number

Atomic mass is the sum of protons and neutrons

Atomic Number (Z) = Atomic mass (A) - Number of Neutrons

₈¹⁸O²⁻

Atomic mass = 18

Atomic number = 8 , gain 2 electron ⇒ total 10 electrons

Configuration : 1s², 2s², 2p⁶ (10 electrons)

Neutrons : 18 - 8 = 10

₉¹⁹F⁻

Atomic mass = 19

Atomic number = 9 , gain 1 electron ⇒ total 10 electrons

Configuration : 1s², 2s², 2p⁶ (10 electrons)

Neutrons : 19 - 9 = 10

₁₀²⁰Ne

Atomic mass = 20

Atomic number = 10

Configuration : 1s², 2s², 2p⁶ (10 electrons)

Neutrons : 20 - 10 = 10

The white Dwarfs are a group of stars that are-

A)Extremely bright and hot
B)Low in brightness but are average to high in temperature
C)Average in brightness but high in temperature
D)Average in brightness and average in temperature

Answers

Answer: A

Explanation:

The white Dwarfs are a group of stars that are extremely bright and hot. Hence option A is correct.

What are stars?

Stars are defined as any large gaseous heavenly body that emits light as a result of its own internal energy sources. Stars are celestial bodies that generate their own energy through the fusing of gases. They resemble bright orbs that burn gas and produce energy. Our solar system's star, the Sun, generates energy through the fusion reaction in which helium transforms into hydrogen.

When a white dwarf first forms, it is extremely hot, but because it has no energy source, it will gradually cool as it emits its energy into space. This implies that the color temperature of its radiation, which is initially high, will gradually decrease and turn red. After using up all of their nuclear fuel, stars like the Sun become white dwarfs.

Thus, the white Dwarfs are a group of stars that are extremely bright and hot. Hence option A is correct.

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Scientist looking for new substances in plants grind up the plants with methanol. This solvent dissolves many plant compounds. However, methanol is flammable and toxic (especially if the vapour is inhaled). Large crystals can be made to help scientists work out what the compounds are made of. Explain how you would make plant-compound crystals using methanol.

Answers

Answer:

See explanation

Explanation:

Crystals can be made from methanol by recrystallizing the plant extract from methanol.

The methanol/water system is heated rapidly using a hot plate and the plant extract dissolves in the heating solution until a clear solution is obtained.

The solution is now cooled rapidly. The interior of the flask used for the re crystallization may even by scratched to assist the quick formation of crystals. Large crystals of plant compounds may be obtained using this method. This process should be carried out in a fume hood because of the toxicity of methanol.

How does the amount of fertilizer affect how many potatoes a plant produces?

Answers

Answer:

Excess fertilizer alters the soil by creating too high of a salt concentration, and this can hurt beneficial soil microorganisms. Over- fertilization can lead to sudden plant growth with an insufficient root system to supply adequate water and nutrients to the plant

Explanation:

State joule thomson effect

Answers

Answer:

In thermodynamics, the Joule–Thomson effect describes the temperature change of a real gas or liquid when it is forced through a valve or porous plug while keeping it insulated so that no heat is exchanged with the environment. This procedure is called a throttling process or Joule–Thomson process

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