what are the only elements that exist in nature as uncombined

Answers

Answer 1

Answer:

The noble gases (Argon, Neon, Xenon, Helium, Krypton, Radon)


Related Questions

Choose the incorrect statement from the following:

(a) The disadvantage of natural gas is that it can not be used directly for burning in homes.
(b) Natural gas is stored under high pressure as compressed natural gas.
(c) Natural gas cannot be used for power generation.
(d) It is difficult to transport natural gas through pipes.

Answers

Answer:

d

Explanation:

Generally, it is transported through pipes so I think statement d is incorrect.

Propose an explanation for why the element carbon, rather than sodium, is important in forming natural polymers?
I need this ASAP

Answers

Carbon has a one-of-a-kind ability to make covalent bonds with a wide range of other atoms. It has the ability to form bonds with other carbon atoms as well as atoms from other elements. Carbon frequently forms polymers as a result of this capacity. A polymer is a big molecule composed of numerous smaller molecules linked together by covalent bonds.

kinetic energy increases as velocity ___

Answers

Answer:

square of it's speed

Explanation:

Answer:

kinetic energy increases as the square of its speed.

1. Hydrogen and nitrogen combine to form ammonia. When nitrogen and hydrogen bond, nitrogen pulls the electrons from hydrogen toward itself. Which statement about the reactants is correct?

A) Hydrogen is oxidized, and nitrogen loses electrons.
B) Hydrogen is oxidized, and nitrogen is reduced.
C) Hydrogen gains electrons, and nitrogen is reduced.
D) Hydrogen is reduced, and nitrogen is oxidized.

2. Which phrase best defines a redox reaction?

A) A reaction in which the number of oxygen atoms is reduced.
B) A reaction in which elements are transferred between different atoms.
C) A reaction is which oxygen combines with different atoms.
D) a reaction in which elements are released from the system.

3.Which statement describes the process of oxidation?

A) Oxidation results in a loss of electrons, so the oxidation number increases.
B) Oxidation results in a gain of electrons, so the oxidation number increases.
C) Oxidation results in a gain of electrons, so the oxidation number decreases.
D) Oxidation results in a loss of electrons, so the oxidation number decreases.

4. Which chemical equation represents a redox reaction?
A) TiCl4(s) + 2H2O(g) → TiO2(s) +4HCl(g)
B) CaO(s) + SiO2(s) → CaSiO3(l)
C) CaCO3(s) → CaO(s) + CO2(g)
D)Fe2O3(s) + 2Al(s) → Al2O3(s) +2Fe(l)

5. Which elements are oxidized and reduced in the reaction below?
Br2 (l) + 2NaI(aq) → I2 (s) + 2NaBr(aq)

A) Bromine (Br) is oxidized, and iodine (I) is reduced.
B) Iodine (I) is oxidized, and bromine (Br) is reduced.
C) Sodium (Na) is oxidized, and bromine (Br) is reduced.
D) Bromine (Br) is oxidized, and sodium (Na) is reduced.

Answers

Answer:

1. Hydrogen is oxidized, and nitrogen is reduced.

2. a reaction in which electrons are transferred between different atoms

3. Oxidation results in a loss of electrons, so the oxidation number increases.

4. Fe2O3(s) + 2Al(s) → Al2O3(s) + 2Fe(l)

5. Iodine (I) is oxidized, and bromine (Br) is reduced.

Explanation:

Just took the test and made a 100

Answer:

OXIDATION UNIT TEST

1. Which statement best explains why magnesium and chlorine combine in a 1:2 ratio?

A. Magnesium has two valence electrons, and chlorine can accept one electron in its outer shell

2. Hydrogen and nitrogen combine to form ammonia. When nitrogen and hydrogen bond, nitrogen pulls the electrons from hydrogen toward itself. Which statement about the reactants is correct?

C. Hydrogen is oxidized, and nitrogen is reduced.

3. C3H8 + 5O2 → 3CO2 + 4H2O + energy

Which type of reaction is shown?

C. combustion

4. Which phrase best defines a redox reaction?

D. a reaction in which electrons are transferred between different atoms

5. Which statement describes the process of oxidation?

D. Oxidation results in a loss of electrons, so the oxidation number increases.

6. Which chemical equation represents a redox reaction?

D. Fe2O3(s) + 2Al(s) → Al2O3(s) + 2Fe(l)

7. Which statement correctly describes the oxidation number of the manganese atom (Mn) in MnI2 and MnO2?

A. Manganese has an oxidation number of +2 in MnI2 and +4 in MnO2.

8. Br2(l) + 2NaI(aq) → I2(s) + 2NaBr(aq)

Which elements are oxidized and reduced in the reaction?

D. Iodine (I) is oxidized, and bromine (Br) is reduced.

9. Which action occurs at an electrode of a galvanic cell?

D. electron transfer

10. Which statement best compares a battery and a galvanic cell?

A. A battery’s source of power is a galvanic cell in which a redox reaction produces electrical energy.

11. Zn + 2H+ → Zn2+ + H2

2Al + 3Cu2+ → 2Al3+ + 3Cu

Which elements are oxidized?

A. zinc (Zn) and aluminum (Al)

12. 2Cr(s) + 3Cu2+(aq) → 2Cr3+(aq) + 3Cu(s)

Which half reaction occurs at the cathode?

B. 3Cu2+(aq) + 6e– → 3Cu(s)

13. Written

14. Written

15. Written

I hope this helps!

Explanation:

I took the test shhh

What could be a reason for the difference between the theoretical and experimental heats of reaction

Answers

Answer:

Theoretical value is the value a scientist expects from an equation, assuming perfect or near-perfect conditions. Experimental value, on the other hand, is what is actually measured from an experiment. Rarely (in fact never) are these numbers the same.

Take the area of a sheet of paper. I know that the area of a rectangle can be found by multiplying the lengths of both sides together. I can assume an 8.5x11 sheet, so I calculate exactly 93.5 square inches. This is my theoretical value. When I actually do the measurements on my paper, it turns out my paper has been slightly cut on one end, or I’m measuring with a shoddy ruler. Therefore, I might measure only 92.8 square inches. This is my experimental value. See thats it’s close, but not exact.

Expanding on this concept, quantum mechanics is so widely accepted in the scientific community because many theoretical values calculated by mathmaticians concurred with experimental values to many, many decimal places. These would be constants such as Plank’s Constant, energy levels of harmonic potentials, and energy levels of the hydrogen atom.

Explanation:

Theoretical result is based on information and mathematics. Trials or experiments are the foundation of experimental result. What ought to occur is theoretical probability. What actually occurs is experimental probability.

What is difference between theoretical and experimental result ?

The definition of theoretical probability. It is not necessary to do the experiment and then analyze the findings for theoretical probability. The theoretical probability, however, represents what you anticipate will occur in an experimnet.

In experimental probability, information is gathered via repeated experimentation. In theoretical probability, data is gathered without doing the experiment by taking into account every possibility that has a chance of occurring.

Thus, difference between the theoretical and experimental heats of reaction the incomplete combustion may result in the formation of carbon and carbon monoxide instead of carbon dioxide and water.

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What will be the primary result of the continuation of the
geologic processes indicated at this location?
Earth's magnetic field will reverse direction.
New oceanic crust will form.
o Continental crust will be forced downward.
Earth's circumference will increase.

Answers

Answer:

B

Explanation:

new oceanic crust will form.

The formation of a new oceanic crust will be the primary result of the continuation of the geologic processes. Therefore, option (B) is correct.

What is the oceanic crust?

The oceanic crust can be described as the uppermost layer of the oceanic portion of the tectonic plates. The oceanic crust is composed of the upper oceanic crust, with pillow lavas complex, and the lower oceanic crust, made of troctolite, and ultramafic cumulates.

The oceanic crust lies above the rigid uppermost layer of the mantle. The crust and the rigid upper mantle layer together compose the oceanic lithosphere.

The oceanic crust is rich in iron and magnesium and composed of mafic rocks. It is thinner than the continental crust less than 10 Km thick but it is denser with 3.0 g/cm³ as opposed to the continental crust.

The oceanic crust displays a symmetrical pattern of positive and negative magnetic lines emanating from the mid-ocean ridge.

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8)
What mass of hydrogen is needed to react with 32 g of copper oxide?
CuO + H2 → Cu + H2O

Answers

Answer:

1.22gram of hydrogen is needed to react

Mole measure the number of elementary entities of a given substance that are present in a given sample. Therefore,  0.40 g mass of hydrogen is needed to react with 32 g of copper oxide.

What is mole?

The SI unit of amount of substance in chemistry is mole. The mole is used to measure the quantity or amount of substance. We know one mole of any element contains 6.022×10²³ atoms which is also called Avogadro number.

Mathematically,

CuO + H[tex]_2[/tex]→ Cu + H[tex]_2[/tex]O

mole of copper oxide=  32 /79.54

                                    =0.40 mole

The mole ratio between copper oxide and hydrogen is 1:1

mole of hydrogen= 0.40 mole

mass of hydrogen = 0.40 mole×1g/mol

                              = 0.40 g

Therefore, 0.40 g mass of hydrogen is needed to react with 32 g of copper oxide.

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Write the balanced chemical equation for the following reaction. Also, classify the
reaction as sythesis, decomposition, single replacement, double replacement, or combustion.
aluminum sulfate + barium chloride —> aluminum chloride + barium sulfate

Answers

Answer:

Explanation:

Al2(SO4)3 + 3BaCl2 ====> 2AlCl3 + 3BaSO4

Sorry forgot to say that it is a double replacement. The Ba goes where there Aluminum is and the Aluminum goes where the Barium is.

The internal balance numbers come from the fact that the ions and complex ions have different valance numbers.

¿Cuál es la partícula mas pequeña del átomo?

Answers

Answer:

Los quarks son ciertamente unas de las partículas más pequeñas del universo. Son elementales, indivisibles y no se pueden romper en piezas menores.

Explanation:

According to the following map, what is a type of mineral found in Mexico?
a Bauxite
b Copper
c Gold
d Zinc​

Answers

Answer:

B. Copper

Explanation:

According to the map, the minerals found there are:

IronSilverCopper

The only mineral given as an option is copper. Therefore, the answer is B.

Why does scientists use atomic watch?​

Answers

Answer:

atomic watch

Explanation:

it is used for the measurement of time.

The reaction is at dynamic equilibrium.
N2 + 3H2 ⇌ 2NH3

Which statement is correct?

(1 point)

The solution has the same concentrations of nitrogen gas and ammonia.
The solution has the same concentrations of nitrogen gas and ammonia.

Nitrogen and hydrogen combine at the same rate that ammonia breaks down.
Nitrogen and hydrogen combine at the same rate that ammonia breaks down.

The solution has the same concentrations of nitrogen and hydrogen gases.
The solution has the same concentrations of nitrogen and hydrogen gases.

Both directions of the reaction have stopped.
Both directions of the reaction have stopped.

Answers

When the reaction N₂ + 3 H₂ ⇌ 2 NH₃ is at dynamic equilibrium, Nitrogen and hydrogen combine at the same rate that ammonia breaks down.

The reaction is at dynamic equilibrium.

N₂ + 3 H₂ ⇌ 2 NH₃

Which statement is correct?

The solution has the same concentrations of nitrogen gas and ammonia. NO. Even though we don't know the equilibrium constant, it is unlikely that N₂ and NH₃ have the same concentrations at equilibrium. Nitrogen and hydrogen combine at the same rate that ammonia breaks down. YES. At the equilibrium, the forward rate is equal to the reverse rate. The solution has the same concentrations of nitrogen and hydrogen gases. NO. Even though we don't know the equilibrium constant, it is unlikely that N₂ and H₂ have the same concentrations at equilibrium. Both directions of the reaction have stopped. NO. The reactions don't stop because the equilibrium is dynamic.

When the reaction N₂ + 3 H₂ ⇌ 2 NH₃ is at dynamic equilibrium, Nitrogen and hydrogen combine at the same rate that ammonia breaks down.

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most elements are (1) metals (2)nonmetals (3)gases (4)made in labs

Answers

Most are metals!!!
None are made in labs everything on earth is made of the elements so they are natural!

can someone help me please


so basically i have to match the vocabulary terms with their definitions ​

Answers

Explanation:

Electrical energy: Kinetic energy caused by moving electrons

Example of energy: lighting

Chemical energy: Energy stored in matter

Example of energy: natural gas

Light energy: a kind of kinetic energy that moves in waves and can be seen

Example of energy: stars

Mechanical energy: Is the sum of an object's kinetic energy and potential energy

Example of energy: dart guns

Answer: Q1.) electrical enegry

      Q2.) light energy  

                Q3.) chemical energy

                Q4.) mechanical energy

Explanation:

Q.1) kinetic energy caused by moving electrons ?

eletrical energy

Q2.) what kind of kinetic energy that moves in waves and can been seen?

       light energy  

Q3.)  energy stored in matter ?

        chemical energy

Q4.) the sum of an object's kinetic and potential energy ?

        mechanical energy

Non Metal _________ electrons and form _________________ ion , called __________

Answers

Answer:

Non Metal atoms gain electrons and form negative ion, called anions

HELP!!

Do you think the number of asteroid samples a pod is carrying could make a difference? Might that explain why the
same strength thruster force caused this pod to have a different change in velocity? Explain your ideas, even if you are
unsure

Answers

How does weight affect the speed of an object? Mass doesn't affect speed directly. It determines how quickly an object can change speed (accelerate) under the action of a given force. Lighter objects need less time to change speed by a given amount under a given force.

https://www.mvorganizing.org/does-the-weight-of-a-car-affect-its-speed/

If a feather and a bowling ball were dropped in a vacuum(only gravity effects the variables), they will hit the ground at the same time. So if the mass keeps changing it, and the pod keeps stopping at different points it will take longer to accelerate or decelerate. I’m not totally sure, but here is an answer.


3. A baseball bat striking a baseball and sending it toward left field is an example
of energy transformation. True or false. Please help it’s due tomorrow!!!

Answers

Answer:

TRUE

Explanation:

what is neutralisation??​

Answers

Answer:

Acid + Base -------> Salt + Water

Explanation:

The reaction between an acid and bases is called a neutralization reaction. The result of the reaction is salt and water. For example, when hydrochloric acid(acid) and sodium hydroxide(base) react they form sodium chloride(salt) and water. Also, heat is evolved.

Example:

HCl + NaOH ----------> NaCl + H2O

HCl is hydrochloric acid.

NaOH is sodium hydroxide which is a base.

NaCl is sodium chloride which is a salt.

H2O is water.


If a car is moved 10 meters and 3 Newton's of force is needed to move the car, what amount of workhas
been done?

Answers

Work required = 30J

This is because work = F * x

F (Newton's force) = 3N

x (car moved) = 10m

Work = 3 * 10 = 30J

How many eggs are in 3 dozen eggs? Use the dimensional analysis for this for practice.

Answers

Answer:

36 eggs

Explanation:

12 eggs in each carton

12 + 12 + 12 = 36 eggs

or 3 * 12 = 36 eggs

Hope this helps, have a nice day/night! :D

the heat energy absorbed or released during a chemical reaction is known as:

Answers

Electricity
Light
Sound
Heat

what is the name of an orchestra that performs the ceremonial music of the royal courts and templates of cambodia
a.ankor wat
b.oneat
c.pinpeat
d.samphor​

Answers

Answer:

pinpeat

According to 3 sources

The pinpeat (ពិណពាទ្យ) orchestra or musical ensemble performs the ceremonial music of the royal courts and temples of Cambodia. The orchestra consists of approximately nine or ten instruments, mainly wind and percussion (including several varieties of xylophone and drums)

Explanation:

PA BRAINLIEST

Kinetic energy is described as

Question 1 options:

Movement


Decreasing energy


Stored energy


Elastic

Answers

I’m pretty sure it’s movement, but I’m not 100%

Answer:

its the movement because kinetic energy means moving not stopping or decreasing

Explanation:

What are 4 enzymes responsible for digestion along with their substrate and end product​

Answers

Answer:

4 enzymes responsible for digestion:

1. Salivary amylase ---- substrate: Starch ---- end-product: Maltose  

2. Lipase  ---- substrate: Lipids (fats and oils) ---- end-product: Fatty acids and glycerol

3. Maltase ---- substrate: Maltose ---- end-product: Glucose

4. Protease ---- substrate: Protein ---- end-product: Amino acids

how many grams of lead (ii) iodide will be precipitated by adding sufficient Pb(NO3)2 to trace with 630mL of 0.268M Ki solution?
2KI(aq)+Pb(NO3)2(aq) → PbI2+2KNO3(aq)​

Answers

The mass of PbI2 produced from a trace amount of 630mL of 0.268M KI solution is 39.2 g.

The equation of the reaction is; 2KI(aq)+Pb(NO3)2(aq) → PbI2(s) + 2KNO3(aq)​

From the question, number of moles of KI = 630/1000 L × 0.268M = 0.169 moles

Now;

2 moles of KI is required to precipitate 1 mole of PbI2

0.169 moles of KI is required to precipitate 0.169 moles × 1 mole/2 moles

= 0.085 moles

Mass of PbI2 = Number of moles of PbI2 × Molar mass

Mass of PbI2 = 0.085 moles × 461.01 g/mol

Mass of PbI2 = 39.2 g

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please help me with this

Answers

Answer:

47. C

48. d

49. a

50. b

51. e

52. c

53. c

54. a

55. b

Explanation:

Identify the location of oxidation in an electrochemical cell.

Answers

Answer:

Anode

Explanation:

Electrochemical cells have two conductive electrodes, called the anode and the cathode. The anode is defined as the electrode where oxidation occurs.

Can someone help me with this chemistry question please?

Answers

C. Energy use

please mark me a brainlist

how do you write the names and formulas for ionic compounds with polyatomics

Answers

Here are some steps i know from my teacher:

When you write a formula from a home you must follow these rules

1) Write down the name you must follow these rules

2)Write down the symbols for the elements and group in the compound of elements

3)Write down the valency

4)Adjust the number of atoms of each element or group valency is the combining capacity of elements with one another.

Consider this reaction: 2H CO32- → H2O CO2. Identify each of the following as a product, a reactant, or a coefficient. CO32-: H2O: CO2: The 2 in front of H :.

Answers

Answer:

The 2 in front of the H is a coefficient.

H and (CO3)2 are reactants.

H2O and CO2 are products.

This reaction is an example of Combustion.

Answer:

CO32-:   reactant

H2O:   product

CO2:   product

The 2 in front of H+:  coefficient

Explanation:

This is the real answer, I got it right on edge or whoever you write it.

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