The scientists who have contributed to our current body of knowledge were
from what part of the world?

A. All areas of the world

B. Mostly Europe

C. Mostly the Middle East

D. Only the United States
SEMIT

Answers

Answer 1

Answer:

A.

Explanation:

Well, Nicola Tesla was from Croatia.

Albert Einstein was from Germany.

Thomas Edison was from the U.S.

So I think all over.

Answer 2
All areas of the world (A)

Related Questions

The pressure of a sample of helium is 1.556 atm in a 268.5 mL container. If the container is compressed to 112.4 mL without changing the temperature, what is the new pressure?
a. 3.72
b. 0.651
c. 1.94e4
d. 277

Answers

Answer:

a.  3.72 [atm]

Explanation:

For a gas at constant temperature, (with no change in number of molecules of the gas), we can apply Boyle's Law:  [tex]P_1V_1=P_2V_2[/tex]

[tex](1.556[atm])(268.5[mL])=P_2(112.4[mL])[/tex]

[tex]\dfrac{(1.556[atm])(268.5[mL\!\!\!\!\!\!\!\!{--}])}{112.4[mL \!\!\!\!\!\!\!\!{--}]}=\dfrac{P_2(112.4[mL]\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!{-----})}{112.4[mL]\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!{-----}}[/tex]

[tex]3.716957[atm]=P_2[/tex]

It seems like the answer should have 4 significant figures since all of the other quantities have 4 significant figures, but the closest answer choice of those provided is a.  3.72

the electron configuration for sodium is 1s22s22p63s1. which subshell is said to contain the valence electron(s) for sodium?

Answers

The subshell that contains the valence electron for sodium is the s subshell

Valence electrons

Valence electrons are the electrons located at the outermost shell of an atom

From the question, we are to determine the subshell that contains the valence electron(s) for sodium

The given electronic configuration for sodium is

1s²2s²2p⁶3s¹

The valence electron is the electron in the 3s orbital.

Hence, the subshell that contains the valence electron for sodium is s subshell

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(100 POINTS) WILL MARK BRAINLIEST
Which of the following explains how one of the postulates in John Dalton's atomic theory was later subjected to change?

Various scientists found that all atoms of a particular element are identical.
Some scientists found that atoms combine in simple whole number ratios to form compounds.
Various scientists found that atoms consist of subatomic particles with varying mass and charge.
Some scientists found that bonds between atoms are broken, rearranged, or reformed during reactions.

Answers

One of the postulates in John Dalton's atomic theory was later subjected to change was that Various scientists found that atoms consist of subatomic particles with varying mass and charge. option C is correct.

What are subatomic particles?

An atom is consist of three sub atomic particles called proton, neutrons and electrons also known as the fundamental nit of an atom.

Atom consist of an nucleus into which proton and neutrons are present and protons are positively charged whereas neutrons are neutral and electrons revolve around the nucleus in the fixed paths called shells and negatively charged.

Therefore, the postulates in John Dalton's atomic theory was later subjected to change was that Various scientists found that atoms consist of subatomic particles with varying mass and charge. option C is correct.

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Answer:

D. some scientists found that bonds between atoms are broken rearranged or reformed during reactions. According to Dalton's other theories, this is the only one that differentiates from his original theories :)

Explanation:

Which feature of a balanced chemical equation demonstrates the law of
conservation of mass?
A. It shows the products of a chemical reaction to the right of the
reaction arrow.
OB. It shows the reactants of a chemical reaction to the left of the
reaction arrow.
C. It has the same types of atoms on both sides of the reaction
arrow.
O
D. It has coefficients to show how much of each substance a
chemical reaction uses.

Answers

Answer:

C. It has the same types of atoms on both sides of the reaction arrow.

What is a chemical equation?

A chemical equation is a symbolic representation of a chemical reaction; Reactants are represented on the left and the products on the right.

The law of conservation of mass states that in a closed system, mass is neither created nor destroyed during a chemical or physical reaction. The law of conservation of mass is applied whenever you balance a chemical equation. It is also applicable to stoichiometry. A balanced equation demonstrates the conservation of mass by having the same number of each type of atom on both sides of the arrow.

Consider the balanced equation for the combustion of methane.

[tex]CH_4 + 20_2 \implies CO_2 + 2H_2O[/tex]

All balanced chemical equations must have the same number of each type of atom on both sides of the arrow.

In this equation, we have 1 C atom, 4 H atoms, and 4 O atoms on each side of the arrow.

The number of atoms does not change, so the total mass of all the atoms is the same before and after the reaction. Mass is conserved.

The same atoms of the same element that are present in the reactants are also present in the products, according to the rule of conservation of matter.

This leads us to believe that the response to the question is true because: It has the same atom kinds on both sides of the reaction arrow (Option C)

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What are chloroethane's conditions?

Please help me
Thanks

Answers

Explanation:

Hi there!

Chloroethane requires atleast one chlorine in ethane. It's general formula is CnH2n+1Cl. It mean it must have 2 carbons, 5 hydrogens and atleast one chlorine.

In addition, carbon-carbon bond must be single and chlorine is attached to either carbons. The carbon of this compound is SP³ hybridized and has bond angle of 120°.

Hope it helps!

it requires on chlorine

Which of these is a mineral?
Folate
Vitamin A
Calcium
Sugar

Answers

Calcium is a mineral.
The answer is C,
Calcium.

What is the mass of a piece of
copper that displaces 3.0 mL
of water and has a density of
9.0 g/cm³?
mass = density x volume

Answers

Answer:

27 gm

Explanation:

Well..... the volume of the copper is   3 cm^3

9.0  g/cm^3    * 3 cm^3 = 27 gm

HELPP!!!
A 6.28 L balloon is filled with water at 3.93 atm. If the balloon is
squeezed into a 3.25 L beaker and does NOT burst, what is the
pressure of water in the balloon?
a. 7.59
b. 2.03
c. 80.2
d. 0.0893

Answers

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What is the mass of the object on this triple beam balance?

Answers

A closer look at the triple beam balance shows that mass of the body is 52.5 g.

What is a triple beam balance?

The term triple beam balance refers to an equipment that is used to determine the mass of an object. It has three different degrees of calibration as shown.

In this case, if we look at the beam balance well, we can see that the mass of the body is 52.5 g.

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What does the author predict about the future of the Earth's mantle? Do you support his educated guess? Use complete sentences to answer.

Answers

The earth's mantle will not change in the future because this region is safe from the intervention of human beings.

What happens in the Earth's mantle?

The transfer of heat and material in the mantle helps us to determine the landscape of Earth. Activity in the mantle moves the plate tectonics, that contributes to volcanoes, seafloor spreading, earthquakes, and building of mountains.

So we can conclude that the earth's mantle will not change in the future because this region is safe from the intervention of human beings.

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write the advantages of molecular formula​

Answers

Answer:

Its main advantage is they information fits on one line of text (thus works well when using the formula in paragraphs). Disadvantages are they can be confusing for larger molecules

hope this helps :3

How many moles of CF4 can be produced when 8.95 mol C reacts with 7.88 mol F2?
How many moles of each reactant are left over? (Note that at least one of the reactants must disappear.)
C remaining
mol
F2 remaining
mol

Answers

The remaining moles of C is 5.01 moles while the remaining moles of F₂ is 0.

Reaction between Carbon and Fluorine

The reaction between carbon and Fluorine is given as;

C + 2F₂  -------> CF₄

1  :    2                1

from the reaction above,

2 moles of F₂ requires 1 mole of C

7.88 mole of  F₂ will require:    7.88/2 = 3.94 moles of C and 3.94 moles of CF₄.

The remaining moles of C = 8.95 - 3.94 = 5.01 moles while the remaining moles of F₂ is 0.

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The pH of a solution is measured as 8.3. What is the hydrogen ion
concentration of the solution?
OA. 2.0 x 108 M
OB. 8.0 x 10-³ M
OC. 8.3 M
OD. 5.0 x 109 M

Answers

Answer:

D.) 5.0 x 10⁻⁹ M

Explanation:

The formula displaying the relationship between pH and hydrogen ion concentration is:

pH = -log[H⁺]

In this formula "[H⁺]" represents the concentration of hydrogen ions (given in molarity (M)). Therefore, to find this value, you need to take the inverse of the log. The manipulation looks like this:

pH = -log[H⁺]  ------------>  [H⁺] = 10^-pH

Note that the carrot (^) represents an exponent. Now, you can plug your pH value into the equation to find the molarity.

[H⁺] = 10^-pH

[H⁺] = 10^-8.3

[H⁺] = 5.0 x 10⁻⁹ M

I will give a brainley Hi guys I need help figuring out where the moderately reactive atoms are located on the periodic table and how the number of balance electrons of the light metals compared to those heavier than born

Answers

The moderately reactive atoms located in the periodic table are fluorine, chlorine, bromine, and iodine which means the halogens family.

The number of balance electrons of the light metals compared to those heavier by listing elements in the order of increasing atomic number.

What are halogen metals?

They are the five non-metals in family 7A of the periodic table. Halogens are chemical elements that form inorganic salts. In the periodic table they are part of group 17 or family 7A.

Halogens are strong oxidants and react mainly with alkali metals (Family I A) which tend to donate an electron. They also react with metals and noble gases (Family VIII A).

The chemical elements are arranged from left to right and top to bottom in order of increasing atomic number, or the number of protons in an atom's nucleus, which generally coincides with increasing atomic mass.

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[tex]\begin{gathered}\\ \underline{\boxed{\large\leadsto\frak \red{ Answer :- }}} \\ \end{gathered}[/tex]

The moderately reactive atoms located in the periodic table are fluorine, chlorine, bromine, and iodine which means the halogens family.

The number of balance electrons of the light metals compared to those heavier by listing elements in the order of increasing atomic number.

What are halogen metals?

They are the five non-metals in family 7A of the periodic table. Halogens are chemical elements that form inorganic salts. In the periodic table they are part of group 17 or family 7A.

Halogens are strong oxidants and react mainly with alkali metals (Family I A) which tend to donate an electron. They also react with metals and noble gases (Family VIII A).

The chemical elements are arranged from left to right and top to bottom in order of increasing atomic number, or the number of protons in an atom's nucleus, which generally coincides with increasing atomic mass.

▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬

A scientist measures the standard enthalpy change for the following reaction to be -139.5 kj :

h2(g) + c2h4(g)c2h6(g)

based on this value and the standard enthalpies of formation for the other substances, the standard enthalpy of formation of c2h4(g) is _____ kj/mol.

Answers

Answer:

A scientist measures the standard enthalpy change for the following reaction to be -139.5 kj :

h2(g) + c2h4(g)c2h6(g)

based on this value and the standard enthalpies of formation for the other substances, the standard enthalpy of formation of c2h4(g) is _____ kj/mol

Explanation:

Hydrogen ΔHof (kJ/mol) ΔGof (kJ/mol) So (J/mol K)

H2 (g)

0

0

130.7

Carbon ΔHof (kJ/mol) ΔGof (kJ/mol) So (J/mol K)

C2H6 (g)

-84.7

-32.8

229.6

The absorption spectrum of sodium is shown below. What do the two dark
vertical lines in the spectrum show about sodium atoms?
Absorption spectrum
700
600
500
400 nm
OA. A sodium atom gives off all wavelengths except those two when
an electron moves to lower energy levels.
OB. A sodium atom gives off those two wavelengths when an electron
moves to a higher energy level.
OC. Only those two wavelengths can cause an electron to move to a
higher energy level.
OD. All wavelengths except those two cause an electron to move to a
lower energy level.
SUBMIT

Answers

The two dark vertical lines in the spectrum shows that all wavelengths except those two cause an electron to move to a lower energy level. Hence, Option (D) is correct

What is Absorption Spectrum ?

A spectrum of electromagnetic radiation transmitted through a substance, showing dark lines or bands due to absorption at specific wavelengths.

The given fact is explained by the energy levels that electrons may be in are quantized, or vary by a specific amount.

When electrons go from one energy level to another, the difference in those energy level is a specific value, and not a range of values.

If they are transitioning upwards towards a higher energy, they will absorb the photons corresponding to the wavelength of light which has the specific amount of energy they need to ascend, resulting in dark lines.

Similarly, when the electrons transition from higher to lower energy, the same specific amount of energy is released and the emission spectrum shows lines in the places where the absorption spectrum was dark.

Hence, The two dark vertical lines in the spectrum shows that all wavelengths except those two cause an electron to move to a lower energy level. Therefore, Option (D) is correct

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Which of the following is the best thermal insulator to reduce the transfer of
thermal energy by radiation?
O A. Air
OB. Glass
O C. Wood
OD. A vacuum

Answers

Among the given mediums, Vaccuum is the best thermal insulator to reduce the transfer of thermal energy by radiation as there will be no air particles which carries heat from one place to other. Hence, Option (D) will be the correct option

What is Heat radiation ?

Heat Radiation refers to the transfer of heat from a hot body to cold body directly, without heating the medium between two bodies.

Vaccum does not have any particles in it. Thus, there will be no transfer of heat through it.

The best example of it is thermous flask in which vaccuum inside thermous flask reduces the transfer of energy through it.

Hence,Among the given mediums, Vaccuum is the best thermal insulator to reduce the transfer of thermal energy by radiation as there will be no air particles which carries heat from one place to other. Thus, Option (D) will be the correct option

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a burning candle wax reacts with oxygen. after a glass jar is placed over it, the candle goes out. what is the limiting reactant?

Answers

If the candle goes out when a glass jar is placed over it, then oxygen is the limiting reactant.

What is a limiting reactant?

The limiting reactant is the reactant that is present in the least amount. When the limiting reactant is exhausted, the reaction comes to a halt.

Thus, if the candle goes out when a glass jar is placed over it, then oxygen is the limiting reactant.

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What happens to the atomic radius when an electron is gained?
OA. The negative ionic radius is larger than the neutral atomic radius
B. The negative ionic radius is smaller than the neutral atomic radi
C. The negative ionic radius is the same size as the neutral atomic
radius.
D. The negative ionic radius does not follow a trend with the neutra
radius.

Answers

A. The negative ionic radius is larger than the neutral atomic radius.

The first step in the formation of all three products is the loss of the ots leaving group to give a carbocation intermediate. this intermediate is resonance-stabilized, and products b and c are generated from a different resonance structure than the one used to generate product a. draw the other resonance structure (using the carbon skeleton provided) and add curved arrow(s) to convert the first resonance structure into the second one.

Answers

The carbocation stabilized by resonance structure and thereby lowers the energy of the carbocation, hydrogen will add to the carbon in the double bond that produces delocalization of electrons.

What is carbocation?

A carbocation is a molecule in which a carbon atom has a positive charge and three bonds.

In general, electrons are stabilized by delocalization. The stabilization energy engendered by delocalization over more than two atoms is called the resonance stabilization energy or simply the resonance energy. The greater the extent of electron delocalization the greater the resonance stabilization.

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Ascorbic acid (vitamin C) has the molecular formula C H₂O (molar mass = 176.12 g/mol) The recommended daily allowance of
ascorbic acid in the diet of a human adult is 0.045 g. How many molecules of ascorbic acid is this?

Select one:

1.54 x 10^20molecules
2.56 x 10^-4molecules
2.71x 10^22 molecules
4.77 x 10^24 molecules

Answers

Answer:

1.54 × 10²⁰ molecules

Explanation:

Dividing the mass by the molar mass, we get the number of moles to be (0.045)/(176.12), which is about 0.0002555 mol.

Avogadro's law states that there are 6.022 × 10²³ molecules in one mole of a substance, so the answer is

(0.0002555)(6.022 × 10²³), which is 1.54 × 10²⁰ molecules.

7.0 mol Mn reacts with 5.0 mol
O2 according to the equation below:
2Mn+0₂ → 2MnO

How many moles of MnO form from7.0 mol Mn?

[?] mol MnO

Round your answer to the tenths place.

Answers

Answer:

= 7 moles Mno

Explanation:

We have been asked to determine the number of moles required to form MnO.

Mole ratio

Mn : MnO = 1 : 1

The reaction ratio therefore is 1 : 1

Thus 7 moles of Mn react to form 7 moles MnO since we have similar ratio.

Answer:

The answer that I got was 7.0.

Explanation:

It said round to the tenths place so put the .0 after the seven and see if that helps.

Help me please, is for my finals!!

Answers

Answer: A

Explanation:

9 protons correspond to fluorine.

The first model shows 9 electrons, so the charge is neutral and is thus a fluorine atom.The second model shows 10 electrons, so the charge is -1, meaning is a fluoride ion.

The average temperature of healthy person is 98.6°F. What is it in
Celsius scale?

Answers

Answer:

37 Degrees Celsius

Explanation:

Which two types of waves can transmit energy through a vacuum?

Answers

Answer:

electromagnetic waves and mechanical waves

Explanation:

I think these two kinds of waves can transmit energy through a vaccume.

Hope I helped!

Electromagnetic waves.

Gravity waves.

An atom is determined to contain 13 protons 10 electrons and 12 neutrons what are the mass number and charge of this atom or ion
Mass number 24 charge +2
Mass number 22 charge neutral
Mass number 34 charge -2
Mass number 34 charge +2

Answers

The mass number and charge of this atom or ion is 24  and charge +2

What is mass number ?

The mass number is equals to the total number of protons and neutrons in a nucleus.

In the give question, The number of neutrons is a distractor.

Only the number of electrons versus the number of protons determines ionic charge. The charge of the ion is +2

Hence, The mass number and charge of this atom or ion is 24  and charge +2

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the pressure of a gas depends on the ____ and ____ of the gas.

Answers

Answer:

Temperature and Volume

Explanation:

PV = n R T

P = n R T / V      pressure depends on the temperature and volume

The pressure of a gas depends on the temperature and volume of the gas.

Ideal gas equation

PV = nRT

Where

P is the pressureV is the volumen is the number of moleR is the gas constantT is the temperature

From the equation given above, we obtained the following:

PV = nRT

Divide both sides by V

P = nRT / V

R is constant and n = 1

P = T / V

Thus, we can see that the pressure (P) is dependent on the temperature (T) and the volume (V)

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Using the information in the table to the right, calculate the enthalpy of combustion of 1 mole of acetylene for the reaction

Answers

The enthalpy of combustion of 1 mole of acetylene for the reaction using the information in the table (attached as figure) is - 1,256 kJ/mol

What is Enthalpy of combustion ?

The enthalpy of combustion of a substance is defined as the heat energy given out when one mole of a substance burns completely in oxygen.

Hence, The enthalpy of combustion of 1 mole of acetylene for the reaction using the information in the table is - 1,256 kJ/mol

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Plants require nitrogen fixed in compounds to grow. A higher the percentage of nitrogen results in improved plant growth. Which compound should you add to your fertilizer to get the best results.

A. N2F2
B. CON2H4
C. (NH4)2SO4
D. NH4NO3

Answers

Explanation:

c and d. I'm not sure which one is better tho

Nitrogen fixation is the part of the nitrogen cycle where the nitrogen is fixed as nitric oxide. Urea {CON₂H₄} should be added to fertilizer to get the best results. Thus, option B is correct.

What are fertilizers?

Fertilizers are substances that are composed of organic and inorganic compounds that are used to provide nutrients to the plants and crops for growth, development, pest, and insect resistance.

The fertilizers mainly comprise nitrogen, potassium, and phosphorus. Urea {CON₂H₄} has the maximum concentration of nitrogen (46%) and will be the most effective.

The other compound ammonium nitrate {NH₄NO₃} contains 34%, ammonium sulfate { (NH₄)₂SO₄} which comprises 21% of nitrogen by mass, whereas N₂F₂ is not used as a fertilizer.

Therefore, option B. Urea {CON₂H₄} is best to use as fertilizer.

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• Reflect on the importance of stoichiometry and rate of chemical reaction in the design of car airbags

Answers

Answer:

If an insufficient amount of nitrogen were produced, the air bag would under inflate and not provide adequate protection. Clearly, the stoichiometry of the reaction is very important.

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