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Rutherford's famous gold foil experiments shot heavy particles at a thin sheet of gold foil. What did he observe, and why did these observations eventually result in the addition of a nucleus to the atomic model?

Some of the heavy particles bounced off the foil, because there are positive particles spread throughout the atom.

Some of the heavy particles bounced off the foil, because there is a dense, positive area in the atom.

The heavy particles all passed straight through the foil, because the atoms are mostly empty space.

The heavy particles all bounced off the foil, because the subatomic particles have mass and volume.

Equilibrium shifts to produce more reactant.

Answer:

7.565 %.

Explanation:

Error % = [True value - Measured value) /True value] ×100

where, True value = 42.3 g.

Measured value = 45.5 g.

Error % = [║(True value - Measured value)║ /True value] ×100

Error % = [║(42.3 g) - (45.5 g)║ /(42.3 g)] × 100 = 7.565 %.

Answer: acid dissociation

Explanation:

According to the Bronsted-Lowry conjugate acid-base theory, an acid is defined as a substance which looses donates protons and thus forming conjugate base and a base is defined as a substance which accepts protons and thus forming conjugate acid.

For the given chemical equation:

[tex]HBr+H_2O\rightarrow H^+(aq.)+Br^-(aq.)[/tex]

Here, [tex]HBr[/tex] is loosing a proton, thus it is considered as an acid and the reaction is acid dissociation.

Hydroium ion is [tex]H_3O^+[/tex]

Neutralization reaction is a chemical reaction in which an acid reacts with base to produce salt and water.

[tex]HA+BOH\rightarrow H_2O+BA[/tex]

Thus the reaction is acid dissociation.

The water molecules in your breath are the gas water vapor. They slow down as they transfer some of their energy to the cold window. The attractions between the slower-moving water vapor molecules bring them together to form tiny droplets of liquid water.

Answer:

The only true statement is:

Explanation:

Alpha particles are radiactive particles equivalent to a helium nucleus, so they have two protons and two neutrons.

Hence, alpha particles, α, are represented as:

The superscript 4 to the left of the chemical symbol is the mass number: 2 protons + 2 neutrons = 4

The subscript 2 to the left of the chemical symbol is the atomic number: 2 protons = 2.

Hence, the statement "a. Alpha particles have a mass number of 4" is true.

As for the other statements, you have:

b. Alpha particles have a nulear charge of +1: false

Since, these particles are the nucleous of the helium atom, the nuclear charge equals the number of protons of this atom: +2. Hence, the statement is false.

c. Alpha particle formation is accompanied by the conversion of a proton into a neutron and d. Alpha particle formation is accompanied by the conversion of a neutron into a proton. (both false)

The conversion of a protons into a neutrons and the conversion of a neutron into a proton are product of other kind of radiactive desintegrations.

Therefore, these last two statements are also false.

True statements about alpha particles include that they have a mass number of 4 and that their formation involves the conversion of a neutron into a proton, whereas their nuclear charge is not +1 but +2.So,option a,d is correct.

In addressing the question about alpha particles, here are the true statements:

a. Alpha particles have a mass number of 4

d. Alpha particle formation is accompanied by the conversion of a neutron into a proton

Alpha particles are indeed equivalent to a helium nucleus with two protons and two neutrons, giving them a mass number of 4. Their charge is actually +2, not +1 as suggested in option b. During alpha decay, the parent nucleus sheds an alpha particle, leading to the creation of a new element with an atomic number reduced by 2 and a mass number decreased by 4. This transformation involves the conversion of a neutron into a proton within the parent nucleus.

Answer:

D) hydrochloric acid.

Explanation:

Zn(s) + 2HCl(aq) → ZnCl₂(aq) + H₂(g),

It is clear that 1.0 moles of Zn react with 2.0 moles of HCl to produce 1.0 moles of ZnCl₂ and 1.0 mole of H₂.

∴ 2.0 mol of Zn (the remaining 2.0 mol is in excess) react completely with 4.0 mol of HCl with (1: 2) molar ratio.

So,

the limiting reactant is HCl and the excess reactant is Zn.

Thus, the right choice is: D) hydrochloric acid.

Final answer:

Explanation on how to determine the limiting reactant in a chemical reaction involving zinc and hydrochloric acid.

Explanation:

The limiting reactant in a chemical reaction is the reactant that gets consumed completely first, limiting the amount of product formed. To determine the limiting reactant, we compare the moles of each reactant to the stoichiometry of the balanced equation.

In the reaction Zn(s) + 2HCl(aq) → ZnCl₂(aq) + H₂(g), if you have 4 moles of zinc and 4 moles of hydrochloric acid, you need to use stoichiometry to see which reactant will be completely consumed first.

Based on the balanced equation, the limiting reactant between zinc and hydrochloric acid is hydrochloric acid as only 2 moles of HCl are needed to react completely with 1 mole of zinc.

Answer:

0.07172 L = 7.172 mL.

Explanation:

where, P is the pressure of the gas in atm (P = 1.0 atm, Standard P).

V is the volume of the gas in L (V = ??? L).

n is the no. of moles of the gas in mol (n = 3.2 x 10⁻³ mol).

R is the general gas constant (R = 0.0821 L.atm/mol.K),

T is the temperature of the gas in K (T = 273 K, Standard T).

∴ V = nRT/P = (3.2 x 10⁻³ mol)(0.0821 L.atm/mol.K)(273 K)/(1.0 atm) = 0.07172 L = 7.172 mL.

To calculate the volume of 3.2 x 10^-3 mol CO2 at STP, we can use Avogadro's Law. The volume can be calculated by multiplying the number of moles by the molar volume of a gas at STP, which is 22.4 liters/mol.

To calculate the volume of gas at STP (Standard Temperature and Pressure), we can use Avogadro's Law. Avogadro's Law states that equal volumes of gases, at the same temperature and pressure, contain the same number of particles (moles).

First, we need to convert the given number of moles of CO2, which is 3.2 x 10^-3 mol, into liters by using the molar volume of a gas at STP, which is 22.4 liters/mol. Multiplying the number of moles by the molar volume gives us the volume:

Volume = 3.2 x 10^-3 mol * 22.4 L/mol = 0.07168 L

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Answer:

D. 86.5 grams

Explanation:

∵ The percentage yield = (actual yield/theoretical yield)*100.

From the balanced reaction:

CaCO₃ + 2HCl → CaCl₂ + CO₂ + H₂O,

It is clear that 1 mol of CaCO₃ reacts with 2 mol of HCl to produce 1 mol of CaCl₂, 1 mol of CO₂, and 1 mol H₂O.

n = mass/molar mass = (95.0 g)/(100.0869 g/mol) = 0.95 mol.

Using cross multiplication:

1 mol of CaCO₃ produce  → 1 mol of CaCl₂, from stichiometry.

∴ 0.95 mol of CaCO₃ produce → 0.95 mol of CaCl₂.

∴ The mass of CaCl₂ (theoretical yield) = (no. of moles) * (molar mass) = (0.95 mol)*(110.98  g/mol) = 105.34 g.

∵ The percentage yield = (actual yield/theoretical yield)*100.

The percentage yield = 82.15%, theoretical yield = 105.34 g.

∴ The actual yield of CaCl₂ = (The percentage yield)(theoretical yield)/100 = (82.15%)(105.34 g)/100 = 86.53 g ≅ 86.5 g.

Answer:

The correct answer is option D.

Explanation:

[tex]CaCO_3 + 2HCl \rightarrow CaCl_2 + CO_2 + H_2O[/tex]

Moles of calcium carbonate = [tex]\frac{95 g}{100.08 g/mol}=0.9492 mol[/tex]

According to reaction,1 mol of calcium carbonate gives 1 mol of calcium chloride.

Then 0.9492 mol of calcium carbonate will give :

[tex]\frac{1}{1}\times 0.9492 mol=0.9492 mol[/tex] of calcium chloride.

Theoretical yield of the calcium chloride = [tex]110.98 g/mol\times 0.9492 mol=105.3422 g[/tex]

Experimental yield of calcium chloride = 95 g

Percentage yield of a calcium chloride = 82.15 %

[tex]\frac{\text{experimental yield}}{\text{Theoretical yield}}\times 100=82.15\%[/tex]

[tex]\frac{\text{experimental yield}}{105.3422 g}\times 100=82.15\%[/tex]

Experimental yield = 86.53 g

The closest option to our answer is option D. Hence, option D is correct answer.

Answer:

A

Explanation:

One of the main complaints about hydropower is that it will change the ecosystem. You can read about the history of any dam and you will find that most of them have involved evacuation. That means that farmland was lost and replaced by a lake behind the dam. The energy comes from water cascading over the top of the dam to its bottom.

It does not produce radiation.

It does not burn fossil fuels. It's clean and does not pollute the air.

So there are no greenhouse gases involoved.

Answer:

change the ecosystem

Explanation:

Answer:

BaCo3 (s)

Explanation:

Because it is being formed from two aqueous solutions, and the (s) indicates that it is a solid. Precipitate means "formed into solid". Since BaCo3 is a product, is solid, is formed from two aqueous solutions, it is a precipitate.

Given that the product is slippery and turns litmus paper blue. It probably contains a base (Option B)

A base is a substance which dissolves in water to produce hydroxide ion, OH¯

A base has been known to neutralize, producing salt and water.

However, a base can easily be tested for by using litmus paper.

A solution of base will turn red litmus paper blue.

With the above information about base, we can conclude that the product described in the question given above contains a base (option B)

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Answer:

[tex]\boxed{\text{CH$_{2}$}}[/tex]

Explanation:

1. Calculate the mass of each element

[tex]\text{Mass of C} = \text{2.67 g } \text{CO}_{2}\times \dfrac{\text{12.01 g C}}{\text{44.01 g }\text{CO}_{2}}= \text{0.7286 g C}\\\\\text{Mass of H} = \text{1.10 g }\text{H$_{2}$O}\times \dfrac{\text{2.016 g H}}{\text{18.02 g } \text{{H$_{2}$O}}} = \text{0.1231 g H}[/tex]

2. Calculate the moles of each element

[tex]\text{Moles of C = 0.7286 g C}\times\dfrac{\text{1 mol C}}{\text{12.01 g C }} = \text{0.060 67 mol C}\\\\\text{Moles of H = 0.1231 g H} \times \dfrac{\text{1 mol H}}{\text{1.008 g H}} = \text{0.1221 mol H}[/tex]

3. Calculate the molar ratios

Divide all moles by the smallest number of moles.

[tex]\text{C: } \dfrac{0.06067}{0.06067}= 1\\\\\text{H: } \dfrac{0.1221}{0.06067} = 2.015[/tex]

4. Round the ratios to the nearest integer

C:H = 1:2

5. Write the empirical formula

The empirical formula is [tex]\boxed{\text{CH$_{2}$}}[/tex]

The empirical formula of the compound is CH.

To find the empirical formula of the compound, we need to determine the molar ratios of carbon and hydrogen in the compound based on the masses of carbon dioxide (CO₂) and water (H₂O) produced during combustion.

First, we calculate the moles of carbon in CO₂:

The molar mass of CO₂ is 44.01 g/mol (12.01 g/mol for C and 2 × 16.00 g/mol for O₂).

Moles of CO₂ = 2.67 g / 44.01 g/mol = 0.0607 mol

Since there is one mole of carbon in one mole of CO₂, the moles of carbon are also 0.0607 mol.

 Next, we calculate the moles of hydrogen in H₂O:

The molar mass of H₂O is 18.015 g/mol (2 × 1.008 g/mol for H₂ and 16.00 g/mol for O).

Moles of H₂O = 1.10 g / 18.015 g/mol = 0.0611 mol

The moles of hydrogen:

Moles of H in H₂O = 2 × Moles of H₂O = 2 × 0.0611 mol = 0.1222 mol

Now, let's re-calculate the molar ratio of carbon to hydrogen:

Moles of C / Moles of H = 0.0607 mol / 0.1222 mol = 1/2

This ratio simplifies to:

C: 1

H: 1

Therefore, the correct empirical formula of the compound is CH, not CH₂ as previously stated. The error in the initial calculation has been corrected, and the correct empirical formula is CH.

Answer:

b. an outermost energy level that is full of electrons.

Explanation:

The reason why atoms combines is to have a complete outermost shell. When the outermost shell or valence shell of atoms are completely filled withe electrons, they become very stable. Noble gases for example, shows no tendency to react with other atoms because their outermost energy level is completely filled.

The tendency to have a completely filled outer energy level is what drives most atoms into bonding.

Atoms often form bonds in ways that lead to full outer levels of electrons, which provides stability, explained by the octet rule.

Atoms often join in a way that each atom will have an outermost energy level that is full of electrons. This principle is known as the octet rule, which states that, atoms seek to have eight electrons in their outermost energy level to achieve a stable configuration similar to that of noble gases. For instance, oxygen has six electrons in its outer shell, and thus needs two more to complete its outermost energy level, which it can get by forming a bond with, say, two hydrogen atoms (each providing one electron).

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answer Delt G = 0 for the equilibrium

Final answer:

At one atmosphere pressure and the normal melting point, the term that equals zero for the conversion of a substance from solid to liquid is ΔG, the change in Gibbs free energy.

Explanation:

The student's question is related to phase transitions and thermodynamics, specifically the transition of a substance from solid to liquid. At one atmosphere pressure and at the normal melting point of the substance, the term that equals zero for the system is ΔG, which is the change in Gibbs free energy.

This is because at the melting point, the system is in equilibrium, and the Gibbs free energy of the solid and liquid phases are equal. As a result, there is no net change in Gibbs free energy during the transition, leading to ΔG = 0, in accordance with the equation ΔG = ΔH-TΔS at equilibrium.

Answer:

because the bread and cheese is absorbing the water whereas if you leave it dry in a moist humid place mold will start to appear

Explanation:

Answer:

Explanation:

The notation of the most common isotope of silicon is:

The superscript, 28, to the left of the chemical symbol, Si, is the mass number, usually identified with the symbol A, and it is the sum of the protons and neutrons.

The subscript, 14, to the left of the chemical symbolr, Si, is the atomic number, Z, which is the number of protons.

Then, you have this equation:

The number of protons is the same for any isotope of the same element. This is, all the isotopic forms of silicon have the same number of prtons: 14

The number of neutrons is determined from the equation A = Z + N, solving for N:

Hence, the most common isotope of silicon has 14 protons and 14 neutrons.

Final answer:

Geothermal energy has a faster renewal rate than natural gas because it utilizes the constant and virtually inexhaustible heat from Earth's core, contrasting with natural gas's slow replenishment rate.

Explanation:

Comparing geothermal energy to natural gas based on their rates of renewal reveals significant differences in their replenishment. Natural gas, a fossil fuel, forms over millions of years from the decay of organic matter under high pressure and temperature. This process is extremely slow, indicating that natural gas has a much slower rate of renewal once extracted from the Earth. In contrast, geothermal energy harnesses the constant heat emanating from the Earth's core, a result of radioactive decay and the original heat from planetary formation. This heat is virtually inexhaustible on human timescales, making geothermal energy effectively renewable with a much faster rate of renewal in practical terms.

The correct statement is: Geothermal energy has a faster rate because a vast amount of heat energy is always present inside Earth's core.

While both resources provide energy, their rates of renewal starkly contrast due to their different origins and mechanisms of replenishment. Natural gas, being a non-renewable resource, does not replenish at a rate that can sustain its consumption. Conversely, geothermal energy, with its endless supply of heat from the Earth's interior, offers a sustainable alternative with minimal environmental impact.

Answer:

allows scientists to avoid the effects of light pollution

Explanation:

Space Observatories are instruments such as telescopes that are used for explorations in space.

The main functions of a space observatory is that it helps scientists to be able to view very clear images of objects that are in space such as stars and other planetary bodies.

Space observatories when used on earth , have the tendency to absorb ultraviolet and infrared rays which can be very dangerous to the health of scientists but when these space observatories are used for explorations in space, it's major benefit is that it protects the scientists from light pollution such as ultraviolet radiation and infrared light.

From the equation,

4 mole of lithium produces 2 mole of lithium oxide

4.37 mol of lithium produces (4.37÷4)x2 mol of lithium oxide

Answer:

C) nitrogen monoxide

Explanation:

Answer:

c

Explanation:

Answer:

I attached the answer as an image. I also drew in the two most acidic hydrogens.

Explanation:

This goes through the 'benzyne' intermediate, meaning it does an E2-looking reaction by expelling a leaving group (chloride) from the adjacent part of the ring using the amide as a strong base. The triple-bonded benzyne has absurd bond angle strain, and is vulnerable to a good nucleophile like an amide ion, and the resultant sp2 anion is then reprotonated by the acid. I didn't draw in the acid-base reaction in step one, or the spectator ion (sodium).

The both major organic products are 3-amino-2-methyltoluene and 4-amino-2-methyltoluene.

The reaction of 4-chloro-2-methyltoluene with sodium amide is an E2 reaction. The abstraction of hydrogen ion by a base and the loss of chloride ion occurs simultaneously leading to the formation of a benzyne intermediate.

This benzyne intermediate is attacked by the amide ion and H3O+ to yield the products; 3-amino-2-methyltoluene and 4-amino-2-methyltoluene. The  detailed mechanism of the reaction is shown in the images attached below.

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Peer review is an Important part of the scientific process as it permits scientist to have their work translated into other language. Therefore, the correct option is option A.

Peer review is the evaluation of a piece of work by one or more people with similar abilities to the creators (peers). It acts as a tool for capable experts in the sector to self-regulate.

Depending on the type of activity and the field or profession it occurs in, such as medicine, peer review can be broken down into a variety of categories. Peer review is an Important part of the scientific process as it permits scientist to have their work translated into other language.

Therefore, the correct option is option A.

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Answer:

They have a definite volume

Explanation:

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Answer: Option (c) is the correct answer.

Explanation:

In solids, particles are held together by strong intermolecular forces of attraction between them. Due to this reason solids acquire a definite shape and volume.

Whereas in liquids, particles are held by less strong intermolecular forces of attraction. As a result, molecules are able to slide past each other. Liquids acquire the shape and volume of a container in which they are kept.

Hence, liquids also show fixed volume.

Thus, we can conclude that property shared by solids and liquids is that they have a definite volume.

Answer:

(a) Au³⁺;  (b) Ag⁺; (c) Cd²⁺; (d) O₂ in acidic media

Explanation:

You've had Trends in the Periodic Table. Now, here are Trends in Standard Reduction Potentials.

Thus, for each pair of half reactions, we need to look only at which one has the more positive standard reduction potential.

(a) Br₂/Au³⁺  

Au³⁺(aq) + 3e⁻ ⟶ Au(s)       1.498 V

Br₂(ℓ) + 2e⁻ ⟶ 2Br⁻(aq)      1.066 V

Au³⁺ is the stronger oxidizing agent.

(b) H₂/Ag⁺  

Ag⁺(aq) + e⁻ ⟶ Au(s)          0.7996 V

H₂(g) + 2e⁻ ⟶ 2H⁻(aq)      -2.33      V

Ag⁺ is the stronger oxidizing agent.

(c) Cd²⁺/Cr³⁺  

Cd²⁺(aq) + e⁻ ⟶ Cd(s)      -0.4030 V

Cr³⁺(aq) + 3e⁻ ⟶ Cr(s)      -0.744   V

Cd²⁺ is the stronger oxidizing agent.

(d) O₂, H⁺/O₂, OH⁻  

O₂(g) + 4H⁺(aq) + 4e⁻ ⟶ 2H₂O(ℓ)         1.224 V

O₂(g) + H₂O(ℓ) + 4e⁻ ⟶ 4OH⁻(aq)       0.401  V

O₂ in acid is the stronger oxidizing agent.

The more potent oxidizing agents in the given pairs are: Br2, Ag+, Cr3+ and O2 under acidic conditions. These substances readily attract and bind with electrons thereby facilitating the oxidation process in a chemical reaction.

In the given pairs, the better oxidizing agents under standard-state conditions are: (a) Br2 in pair Br2 and Au3+, because Br2 gains electrons more readily. (b) Ag+ in pair H2 and Ag+, since Ag+ has a higher reduction potential. (c) Cr3+ in pair Cd2+ and Cr3+. Lastly, (d) O2 in acidic media tends to be a stronger oxidizing agent than O2 in basic media because more readily available H+ ions in acidic conditions facilitate the oxidation process.

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In unsaturated fatty acids, the cis double bonds cause the carbon chain to bend or "kink", which gives the molecules an irregular shape.

Unsaturated fatty acid carbon chains contain one or more double bonds with a terminal carboxylic group (–COOH), unlike saturated fatty acids, which contain no double bonds. These fatty acids are subdivided into two groups depending on the number of double bonds. A single double bond is termed monounsaturated, and those with more than one double bond are termed polyunsaturated.

In addition to nomenclature systems describing the number of carbon atoms and location of the double bond(s), a “cis-” or “trans-” notation describes the configuration. A cis- notation means hydrogen atoms are on the same side as the carbon double bond, As a result, cis fatty acids cannot stack as closely as saturated fatty acids and thus have fewer dispersion forces between their carbon chains.

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Answer:   D.  400

Explanation:  The given image of the graph explains the relation between the pressure and the temperature of the substance.

Through this graph, one can find the approximate vapor pressure at any phase of the substance.

Thus as we can observe from the graph that the  the approximate vapor pressure when the gas condenses at 80°C is 400.

I think the answer would be True

Answer:

11.21 L.

Explanation:

where, P is the pressure of the gas in atm (P = 1.0 atm, Standard P).

V is the volume of the gas in L (V = ??? L).

n is the no. of moles of the gas in mol (n = 0.5 mol).

R  is the general gas constant (R = 0.0821 L.atm/mol.K),

T is the temperature of the gas in K (T = 273 K, Standard T).

∴ V = nRT/P = (0.5 mol)(0.0821 L.atm/mol.K)(273 K)/(1.0 atm) = 11.21 L.

Answer:

D

Explanation:

100% on test

The correct answer is: to lend credibility and additional support to their conclusion.

In the excerpt from Levitt and Dubner Freakonomics, the authors are discussing the intersection of morality and economics through the example of a bagel business that operates on an honor system. Despite the predictions of economists that such a system would fail due to rampant theft, the business succeeds because most people choose not to steal even when unsupervised.

The authors then reference Adam Smith's The Theory of Moral Sentiments, where Smith discusses the innate honesty and empathy within humanity.

 The purpose of including the quotation from Adam Smith is not merely to showcase their knowledge of the Scottish philosopher, as this would be more of a display of erudition rather than a contribution to their argument.

Similarly, they are not using the quotation to prove that people are inherently dishonest, as Smith's work actually suggests the opposite that there is an inherent honesty and concern for others in human nature.

The authors also do not use the quotation to argue that incentive is the driving force behind cheating.

While incentives are a significant topic in economics and are discussed in Adam Smith's other major work, The Wealth of Nations, the quotation provided here emphasizes the natural inclination towards honesty rather than the role of incentives in promoting dishonesty.

 Instead, the authors use Smith's quotation to lend credibility and additional support to their conclusion that the honor-system scheme works because of an inherent sense of morality in most people.

By invoking a respected economist and moral philosopher who argued for the existence of moral principles that guide human behavior, even when there is no direct benefit to oneself, Levitt and Dubner strengthen their argument that moral behavior can prevail in economic transactions, contrary to what might be expected based on pure economic self-interest.

Adam Smith's authority in both economics and moral philosophy makes his perspective particularly relevant and persuasive in supporting the authors' observations about human behavior in the context of the bagel business.

The answer is in the photo.