The mystery of periodic law was solved when __________ proposed his planetary atomic model of the atom, providing an understanding of the electronic structure of the elements and the organization of electrons into shells.
A) Bohr
B) Rutherford
C) Heisenberg
D) Schrödinger

Chris the Chemist was working in the lab, and he wanted to see what would happen if he put copper chloride into a Bunsen burner flame. As soon as he put it in the flame, it began to emit a green color. Which of these BEST describes this outcome?
A) The heat split the nucleus and created a new element.
B) As the copper chloride was heated, electrons were turned into neutrons.
C) As the electrons moved to a higher energy level, a photon of light is emitted.
D) When excited electrons return back to the ground state, a photon of light is emitted.

Boron has two naturally-ocurring isotopes. Boron-10 has an abundance of 19.8% and actual mass of 10.013 amu, and boron-11 has an abundance of 80.2% and actual mass of 11.009 amu. What is the average atomic mass for all isotopes of boron?
A) 10.0 amu
B) 10.5 amu
C) 10.511 amu
D) 10.812 amu

Given:

Density:8.92g/cm3

Volume:25.8 mL

Now we know that

Mass = density X volume

Substituting the given values in the above equation we get:

Mass = 8.92 x 25.8= 230.136 g

= 230136 mg

Final answer:

To find the mass of a copper sample in milligrams, calculate the mass using density and volume (mass = density × volume), resulting in 230.016 g, and convert to milligrams to get 230016 mg.

Explanation:

The question asks to find the mass of a sample of copper in milligrams, given its density is 8.92 g/cm3 and it occupies a volume of 25.8 mL. First, we need to recall that density is defined as mass over volume (d = m/v), which means mass can be calculated as m = d × v. Given the density of copper (8.92 g/cm3) and the volume of the sample (25.8 mL, which is equal to 25.8 cm3 because 1 mL = 1 cm3), we can calculate the mass in grams and then convert it to milligrams.

To calculate the mass in grams: mass = 8.92 g/cm3 × 25.8 cm3 = 230.016 g. To convert this into milligrams (remembering that 1 g = 1000 mg), we multiply by 1000, resulting in 230016 mg.

Therefore, the mass of the copper sample is 230016 milligrams.

Answer:

The application of X-rays in the hospital.

Explanation:

An X-ray is a painless and brisk method generally used in order to generate inside images of the body. The X-rays are generally carried out in the X-ray departments in the hospital under the guidance of trained specialists known as radiographers, however, it can also be performed by other healthcare professionals.

We have that for the Question "Calculate the activation energy for the reaction" it can be said that The  activation energy is

From the question we are told

Generally the equation for the Activation energy  is mathematically given as

[tex]10(\frac{kr}{ki})=\frac{Ea}{2.303R}(\frac{1}{t_1}-\frac{1}{t_2}})\\\\Therefore\\\\10(\frac{0.0815}{0.0796})=\frac{Ea}{2.303*8.314}(\frac{1}{1010}-\frac{1}{1220}})\\\\Ea=\frac{0.01024}{8.9*10^{-6}}/mol\\\\[/tex]

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The activation energy for the reaction is 96.8 kJ/mol.

To calculate the activation energy for the reaction, we can use the Arrhenius equation: k = Ae-Ea/RT, where k is the rate constant, A is the pre-exponential factor, Ea is the activation energy, R is the gas constant, and T is the temperature in Kelvin. We are given the rate constants at two different temperatures, so we can set up two equations:

k1 = A e-Ea/(R × T1)

k2 = A e-Ea/(R × T2)

Dividing the second equation by the first equation, we get:

(k2/k1) = (A e-Ea/(R ×T2))÷(A e-Ea/(R ×T1))

Simplifying, we get:

eEa/R = (k2/k1) ×(T2/T1)

Taking the natural logarithm of both sides, we can solve for the activation energy:

Ea = -R × ln((k2/k1) × (T2/T1))

Using the given values, we can plug in and calculate the activation energy:

Ea = -8.314 J/mol ×K × ln((0.0815 m-1 × s-1)/(0.0796 m-1 × s-1) × (947 + 273)/(737 + 273)) = 96.8 kJ/mol

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48 grams of CO₂ contains approximately 6.56 x 10²³ carbon atoms, whereas 12 grams of pure carbon contains exactly 6.022 x 10²³ carbon atoms. Hence, 48 grams of CO₂ has more carbon atoms than 12 grams of pure carbon.

Comparing Carbon Content in CO₂ and Pure Carbon

To determine which sample contains more carbon atoms, we first need to consider their molar masses and the mass of carbon in each. The atomic mass of carbon is approximately 12 u, and one mole of a substance contains Avogadro's number of particles, which is roughly 6.022 x 10²³ particles/mole.

For CO₂ (molar mass approximately 44 g/mol), 48 grams corresponds to approximately 48 g / 44 g/mol = 1.09 moles of CO₂. Since each mole of CO₂ contains one mole of carbon atoms, there would be 1.09 moles of carbon atoms in 48 grams of CO₂.

For pure Carbon, 12 grams corresponds directly to 12 g / 12 g/mol = 1 mole of carbon since its molar mass is 12 g/mol. This equals 1 mole, or 6.022 x 10²³ carbon atoms.

Given that 1 mole of a substance contains 6.022 x 10²³ atoms:

48 grams of CO₂ has 1.09 moles x 6.022 x 10²³ atoms/mole = 6.56 x 10²³ carbon atoms.

12 grams of pure carbon has 1 mole x 6.022 x 10²³ atoms/mole = 6.022 x 10²³ carbon atoms.

Therefore, 48 grams of CO₂ has more carbon atoms than 12 grams of pure carbon.

The answer is 125 gms.

Answer:

first half of 1000gram=1000/2=500g

second half of 1000gram=500/2=250g

third half of 1000gram=250/2=125 g

Explanation:

in simple

third half of 1000 g=1000/(2³)=125gram

Aside from Earth, which inner planet once had liquid water on its surface? (Mars)

Aside from Earth, mars is one if the inner planets  which once  had liquid water on its surface.

A planet is a large, rounded astronomical body that is neither a star nor its remnant. The best available theory of planet formation is the nebular hypothesis, which posits that an interstellar cloud collapses out of a nebula to create a young protostar orbited by a protoplanetary disk. Planets grow in this disk by the gradual accumulation of material driven by gravity, a process called accretion.

The Solar System has at least eight planets: the terrestrial planets Mercury, Venus, Earth and Mars, and the giant planets Jupiter, Saturn, Uranus and Neptune. These planets each rotate around an axis tilted with respect to its orbital pole. All of them possess an atmosphere, although that of Mercury is tenuous, and some share such features as ice caps, seasons, volcanism, hurricanes, tectonics, and even hydrology.

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Answer:

C

Explanation:

Ca+2 and Na+ do not hydrolyze to form an acidic solution because they are obtained from an alkali.

Answer: Inertia is based only on an object’s mass.

Explanation:

Any physical object's resistance towards any change in its velocity is known as inertia.

Therefore, more is the mass of an object, the more inertia will be there.

Thus, we can conclude that inertia is based only on an object’s mass and not on velocity.

The correct answer is option A which is mass.

Given:

E = 7.3 × 10–17 Hz                                                                                      

 h= 6.63 × 10–34 J•s

Now E = hf

where E is the energy of the photon                                                          

h is the Planck's constant                                                                          

f is the frequency of the photon

Substituting the values in the equation we get                                        

E= 7.3 × 10^-17 × 6.63 × 10^-34                                                                  

E= 4.8399 × 10^-50  J.                                                                                                      

The energy of the photon, to the nearest tenths place, is 4.8399 × 10⁻⁵⁰ J.

Energy of the photon can be calculated as :

E = hυ, where

E = energy of the photon = to find?

h = plank's constant = 6.63 × 10⁻³⁴ J•s (given)

and υ = frequency = 7.3 × 10⁻¹⁷ Hz

Now putting all these values in the above equation, we get

E = (6.63 × 10⁻³⁴) × (7.3 × 10⁻¹⁷)

E = 4.8399 × 10⁻⁵⁰ J.

Hence, 4.8399 × 10⁻⁵⁰ J is the energy of the photon.

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B. because the little number below the H stands for how many atoms there are, and b has 1 more Hydrogen atom than A does.

(I think)

ans is B) 2 moles of CH₄

because it has 4 Hydrogen atoms per molecule, 1 more than NH3 has.

Hi!

Why is second ionization energy larger than first ionization energy?

The reason second ionization energy is larger is because it takes more energy to remove an electron from a poistively charged ion than it does from an neutral atom.

Ionization energy is the energy required to remove an electron from a neutral atom. When an electron is removed from an atom, the neutral atom becomes positively charged. When another electron is attempted to be removed from the same atom,this requires more energy than the first one, as the attractive force between the electrons and protons are greater owing to the presence of the extra proton. In order to break this force we need more energy to remove the second electron. Hence the second ionization energy is greater than the first ionization energy.

The cladogram of the kingdom Animalia shows the relationship of selected animals based on their shared anatomical features. The black numbered squares represent features that are critical for forming each branch in the animal kingdom. Square one represents a dorsal nerve cord, which means the animals in all the branches have a dorsal nerve cord.

Which numbered square would represent the trait "mammary glands

Answer - C. 5

Control or controlled group is the part of the experiment where conditions are kept the same.

1 mole has mass = 56 g  

0.28 mol has mass = 56 x 0.28 = 15.68 g

Hope this helps!

Final answer:

To calculate the mass of 0.28 moles of iron, multiply the number of moles by the molar mass of iron, which is 55.85 g/mol, resulting in a mass of 15.638 grams.

Explanation:

To find the mass of 0.28 moles of iron, we need to use the molar mass of iron. The molar mass of iron (Fe) can be found on the periodic table and it is approximately 55.85 grams per mole.

Step 1: Molar Mass of Iron

First, we establish the molar mass of iron is 55.85 g/mol.

Step 2: Calculate the Mass

Next, we multiply the number of moles by the molar mass of iron to calculate the mass.

Mass = moles × molar mass

Mass = 0.28 moles × 55.85 g/mol

Mass = 15.638 grams

Hey there!:

1 mole of  C6H12O6 ------------------ 6 moles of C

3.0 moles of C6H12O6 ------------- ??

3.0 *6 / 1 =>

18.0 moles of C

Hope that helps!

Answer:

18.0

Explanation:

Answer:

Monosaccharides!

Explanation:

monosaccharies are the building blocks of all carbohydrates! Starch and glycogen are carbs that consist of multiple monos.

milligrams. kilograms are too big.

Answer:

B) Milligrams

Explanation:

just did the test on usatestprep

Answer;

Compounds of carbon and hydrogen

Explanation;

An organic compound is any of a large class of chemical compounds in which one or more atoms of carbon are covalently linked to atoms of other elements, most commonly hydrogen, oxygen, or nitrogen.

The primary difference between organic compounds and inorganic compounds is that organic compounds always contain carbon while most inorganic compounds do not contain carbon. Additionally, nearly all organic compounds contain carbon-hydrogen or C-H bonds.

Organic compounds includes nucleic acids, fats, sugars, proteins, enzymes and hydrocarbon fuels. All organic molecules contain carbon, nearly all contain hydrogen, and many also contain oxygen.

Answer:

Compounds of carbon and hydrogen

Now ,

C + O2  → CO2

According to above equation, 1 mole of carbon reacts with one mole of oxygen to produce one mole of carbon dioxide.Thus this implies that 12 g of carbon reacts with 32 g of O2 to produce 44 g of CO2.

No of moles = mass of the substance/molecular mass of the substance.

In this case 1.2 g of carbon reacts with "x "g of O2 to produce 4.4 g of CO2.

No of moles of carbon in this case = 1.2÷ 12 = 0.1 moles.

No of moles of carbon dioxide formed = 4.4÷44 =0.1 moles

Thus already discussed above, 1 mole of carbon reacts with 1 mole of oxygen to produce 1 mole of carbon dioxide. Hence to produce 0.1 mole of CO2 ,0.1 mole of carbon needs to react with 0.1 mole of oxygen.

Also number of moles of O2 = mass of O2÷ molar mass of O2

Substituting number of moles of O2 as 0.1 we get

mass of O2(x)  = Number of moles of O2 × Molar mass of O2

Mass of O2 (x) = 0.1 × 32= 3.2 g

Thus mass of 3.2 g O2 reacts with 1.2 g of CO2 to produce 4.4 g of CO2.

In the reaction between carbon and oxygen to form carbon dioxide, the amount of oxygen reacted can be calculated by subtracting the mass of carbon used from the mass of carbon dioxide formed. In this case, approximately 3.2 g of oxygen reacted with 1.2 g of carbon to produce 4.4 g of carbon dioxide.

In the reaction between carbon and oxygen to form carbon dioxide, the amount of oxygen reacting can be calculated using stoichiometry. The balanced chemical equation for this reaction is C + O2 -> CO2. According to this equation, each mole of carbon reacts with one mole of oxygen to produce one mole of carbon dioxide.

Knowing that the molar mass of carbon is about 12.0 g/mol and carbon dioxide is approximately 44.0 g/mol, we can figure out the amount of oxygen that reacted. If the experiment has resulted in 4.4 g of carbon dioxide from 1.2 g of carbon, the amount of oxygen that participated may be calculated as follows: the difference between the mass of carbon dioxide formed (4.4 g) and the mass of carbon used (1.2 g) gives the mass of oxygen. Therefore, 4.4 g - 1.2 g equals 3.2 g of oxygen.

This shows that in the given reaction, approximately 3.2 g of oxygen reacted with 1.2 g of carbon to produce 4.4 g of carbon dioxide.

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The weather would be around the same maybe dropping 5 degrees.

Barometric pressure is the measurement of air pressure in the atmosphere.

A barometer that has a high reading — meaning high pressure — and is stable, indicates good weather.

If one of the station models were to show that the barometric pressure was steadily dropping and the current weather condition showed a slight drizzle with the temperature of 65 degrees then would be around the same maybe dropping 5 degrees.

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First you can take cotton balls, and make a model.

So first make a circle of cotton balls to resemble the eye of a hurricane.

Hurricanes are not round so, when your creating the outside if the eye make it took like the hurricane has bands.

One you create the model, you can simply write things you know about the hurricane, etc.

Examples of thing's you can say:

-The peak of hurricane season is September.

-Hurricane season starts in June.

-September is one of the most active month for hurricanes.

It would be D. Enzymes breaking down the food. Enzymes are used to speed up chemical reactions

Answer: Option (D) is the correct answer.

Explanation:

A change that does not bring any difference in chemical composition of a substance are known as physical change.

For example, shape, size, mass, volume, density, etc of a substance are all physical properties.

Whereas a change that brings difference in chemical composition of a substance is known as chemical change.

For example, precipitation, reactivity, toxicity etc are chemical property.

During break down of food, salivary amylase breaks down starch into simple sugars. In stomach the enzyme pepsin converts protein into peptones in presence of acidic medium. Small intestine receives both intestinal and pancreatic juices (chemical substances) and the final digestion of fats, proteins and sugars occurs here.

Thus, we can conclude that example of a chemical change during digestion is enzymes breaking down food.

Carolus Linnaeus is responsible.

Aluminium most often has an oxidation state of +3 because it has three valence electrons that are removed relatively easily.

Al is in Group 13, so it has three valence electrons.

To get a complete octet, it must either lose three electrons or gain five.

It is easier to remove three electrons, so Al most often has an oxidation state in its compounds.

Final answer:

Aluminum typically has a +3 oxidation state because it loses all three valence electrons in its outer shell during oxidation, forming an Al³+ ion. This oxidation state is maintained in both ionic and covalent aluminum compounds to achieve stability and comply with electrical neutrality in compounds like Al₂O₃.

Explanation:

Aluminum commonly exhibits an oxidation state of +3 because it has three valence electrons in its outer shell (ns²np¹ configuration). When aluminum atom is oxidized, it tends to lose all three of these electrons, resulting in an Al³+ ion with a +3 oxidation state. Transition metals, in comparison, have multiple oxidation states because they can lose electrons from both their s and d orbitals. This is not as straightforward for aluminum, which has only p orbital electrons to lose.

While in many compounds of aluminum, such as AlF3 and Al₂(SO₄)₃, the oxidation state is represented as ionic, some aluminum-containing compounds are covalent. However, in both cases, aluminum adopts a +3 oxidation state to achieve stability. In aqueous solutions, aluminum salts dissociate to release [Al(H₂O)₆]³+ cations, demonstrating aluminum's charge even when coordinated. Furthermore, during redox reactions, aluminum is oxidized by losing three electrons to give a +3 charge, which complies with the electrical neutrality essential in ionic compounds like Al₂O₃.

In a Directly proportional graph, a straight line will be observed between two variables and inversely proportional graph no straight line will be observed between two variables.

So, from this, we can conclude that in a :

Directly proportional graph, a straight line will be observed between two variables, and inversely proportional graph no straight line will be observed between two variables.

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Given:

Density: 0.93 g/mL                                                                              

 Mass: 23 g

Volume = Density/Mass

Substituting the given values in this equation we get

Volume = 23 g ÷ 0.93 g/ mL                                                            

 Volume = 24.73 mL

Fatty acids are carboxylic acids with a carboxylate group and a hydrocarbon chain. Saturated fatty acids have no double bonds and are fully 'saturated' with hydrogen, while unsaturated fatty acids contain one or more double bonds and have fewer hydrogen atoms.

Differences and Similarities Between Saturated and Unsaturated Fatty Acids

Fatty acids are carboxylic acids that serve as building blocks for various types of lipids. All fatty acids have a carboxylate group (-COOH) attached to a hydrocarbon chain. The primary difference between saturated and unsaturated fatty acids lies in the hydrocarbon chain's bond types. In saturated fatty acids, all the carbons are connected by single covalent bonds, and each carbon atom is 'saturated' with hydrogen atoms. This means that there are no double or triple bonds, allowing for the maximum number of hydrogen atoms to be attached to the carbon skeleton. Stearic acid is an example of a saturated fatty acid. On the other hand, unsaturated fatty acids contain one or more double bonds within the hydrocarbon chain. These double bonds reduce the number of hydrogen atoms attached to the carbon skeleton. They are called unsaturated because they do not contain the maximum amount of hydrogen possible.

Answer is  A - HCl is the titrant and D-NaOH is the analyte.

In a titration process, the solution of unknown concentration considered is the analyte. During titration, a standard solution(titrant) is added to an analyte until the equivalence point is achieved.

So in this case as the concentration of NaOH is not known,NaOH is the analyte.

Titrant is the solution whose concentration  is known to us and is added to an analyte until the equivalence point is reached. In this case since we know the concentration of HCl, HCl is the titrant.

Aluminum hydroxide [tex]\text{Al}(\text{OH})_3[/tex] can behave as a base and neutralize sulfuric acid [tex]\text{H}_2\text{SO}_4[/tex] as in the following equation:

[tex]2\;\text{Al}(\text{OH})_3 \; (s) + 3\; \text{H}_2\text{SO}_4 \; (aq) \to \text{Al}_2(\text{SO}_4)_3 \; (aq) + 6 \; \text{H}_2\text{O} \; (l)[/tex] (Balanced)

(a)

[tex]n = m/M[/tex]. Thus the ratio between the number of moles of the two reactants available:

[tex]n(\text{Al}(\text{OH})_3, \text{supplied}) / n(\text{H}_2\text{SO}_4, \text{supplied})\\= [m(\text{Al}(\text{OH})_3)/ M(\text{Al}(\text{OH})_3)] / [n(\text{H}_2\text{SO}_4) / M(\text{H}_2\text{SO}_4)]\\= [23.7 / (26.98 + 3 \times(16.00 + 1.008))]/[29.5 / (2 \times 1.008 + 32.07 + 4 \times 16.00)]\\\approx 1.01[/tex]

The value of this ratio required to lead to a complete reaction is derived from coefficients found in the balanced equation:

[tex]n(\text{Al}(\text{OH})_3, \text{theoretical}) / n(\text{H}_2\text{SO}_4, \text{theoretical}) = 2/3 \approx 0.667[/tex]

The ratio for the complete reaction is smaller than that of the reactants available, indicating that the species represented on the numerator, [tex]\text{Al}(\text{OH})_3[/tex], is in excess while the one on the denominator, [tex]\text{H}_2\text{SO}_4[/tex], serves as the limiting reagent.

(b)

The quantity of water produced is dependent on the amount of limiting reactants available. [tex]29.5 / (2 \times 1.008 + 32.07 + 4 \times 16.00) = 0.301 \; \text{mol}[/tex] of sulfuric acid is supplied in this reaction as the limiting reagent. [tex]6[/tex] moles of water molecules are produced for every [tex]3[/tex] moles of sulfuric acid consumed. The reaction would thus give rise to [tex]0.301 \; \text{mol} \times 6/3 = 0.602 \; \text{mol}[/tex] of water molecules, which have a mass of [tex]0.602 \times (2 \times 1.008 + 16.00) = 10.8 \; \text{g}[/tex].

(c)

[tex]\text{Percentage Yield}\\= \text{Actual Yield} / \text{Theoretical Yield} \times 100 \; \%\\= 2.21 / 10.8 \times 100 \; \%\\= 20.4 \; \%[/tex]

(d)

The quantity of [tex]\text{Al}(\text{OH})_3[/tex], the reactant in excess, is dependent on the number of moles of this species consumed in the reaction and thus the quantity of the limiting reagent available. The consumption of every [tex]3[/tex] moles of sulfuric acid, the limiting reagent, removes [tex]2[/tex] moles of aluminum hydroxide [tex]\text{Al}(\text{OH})_3[/tex] from the solution. [tex]0.301 \; \text{mol}[/tex] of sulfuric acid is initially available as previously stated such that [tex]0.301 \; \text{mol} \times 2/3 = 0.201 \; \text{mol}[/tex], or [tex]0.201 \times (26.98 + 3 \time (16.00 + 1.008)) = 15.7 \; \text{g}[/tex], of [tex]\text{Al}(\text{OH})_3[/tex] would be eventually consumed.

[tex]23.7 - 15.7 = 8.0 \; \text{g}[/tex] of [tex]\text{Al}(\text{OH})_3[/tex] would thus be in excess by the end of the reaction process.