If nitrogen (N) has 2 naturally occurring isotopes, nitrogen-14 (78.3%) and nitrogen-16 (21.7%), what is its average r.a.m.?

Answer:

[tex]\boxed{\text{The train is speeding up by 0.0625 m/s every second}}[/tex]

Explanation:

Acceleration (a) is the change in velocity (Δv) divided by the change in time (Δt).

[tex]a = \frac{\Delta v}{\Delta t} = \frac{v_{2} - v_{1} }{t_{2} - t_{1}} \\\\a = \frac{25 - 10}{240 - 0}=\frac{15 }{240}=\text{0.0625 m/s}^{2}\\\\\ \boxed{\textbf{The train is speeding up by 0.0625 m/s every second}}\\[/tex]

The longer the day, the solar radiation is absorbed and the higher the temperature is.

I hope you have a great rest of your day!

❤

Answer:

B

Explanation:

If the temperature of the water goes up, the reaction is exothermic (heat is being given away by the equation -- more precisely the reactants of the equation). Only A and B can be true. In order for the reaction to occur, the water has to absorb the heat. It's temperature goes up. Remember that minus sign. It is almost the key fact for this question.

The question is not as hard as it looks, but that is easy for me to say.

m = 100 g

c = 4.2 J/(g * oC)

deltaT = 21 - 20 degrees = 1 degree.

Heat = 100 * 4.2 * 1

Heat = 420 J

Heat = 420 * [1 kJ/1000 J]

Heat = -0.42 kJ

B

Answer:

[tex]\boxed{\text{The line spectra of stars indicate which elements are present.}}[/tex]

Explanation:

Each element has a characteristic spectrum, so analyzing the line spectra of stars tell you what elements are present.

A is wrong. The statement is true, but its not the reason why astronomers study stars.

B is wrong. The colour is a function of the star's temperature.

D is wrong. Line spectra give no information on the size of stars.

The study of metals in chemistry is called inorganic metals.

The correct option is C.

Each metal when burns give the color due to the replacement of the electron because the amount of energy is increased due to heat.

According to the question, the rest of the option is wrong because they don't have any link with the hint.

Hence, the correct option is C that is the line spectra of stars indicating which elements are present.

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Isolated systems does not allow any matter or energy to be exchanged.

Isolated system does not allow for matter or energy to be exchanged outside the system.

Isolated system is a thermodynamic system that does not allow the exchange of either matter or energy outside the system.

Open system is a thermodynamic system that can exchange the matter and energy with its surrounding.

A closed system is a thermodynamic system in which the exchange of energy is allowed but the exchange of matter is not allowed outside the system.

Thus, from the above conclusion we can say that Isolated system does not allow for matter or energy to be exchanged outside the system.

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D. Pentane. Pentane has 5 Carbon and 12 Hydrogen, like the molecule shown.

Answer:

Explanation:

NO₂ and N₂O₄ undergo the following equilibrium reaction:

That is a reversible reaction, i.e. there are two simultaneous reactions: the direct or forward reaction and the reverse reaction:

At the beginning, only NO₂(g) is in the sealed container. The NO₂ concentration is maximum, and the rate of the forward reaction is maximum.

As the reaction progresses, the concentration of NO₂ diminishes, and, consequently, the rate of the forward reaction decreases.

As soon as the N₂O₄ appears, the reverse reaction starts. At the beginning the rate is low, but as the N₂O₄ concentration increases the rate of the reverse reaction increases.

When both forward and reverse rates become equal the equilibrium has been reached. This is what is called a dynamical equilibrium.

Then, as per the choices, you have that, at equilibrium:

A) No N₂O₄ is present:

B) No chemical reactions are occurring.

C) The rates of the forward and reverse reactions are equal.

D) The maximum number of molecules has been reached.

You would have to use the molarity of calcium hydroxide to find the moles of calcium hydroxide. Once you have moles, just convert using mole:mole ratio and find the grams of sodium hydroxide.

Answer:

master, family member, family room

The best order of choices listed from best to worst is master bedroom, family member’s bedroom, family room.

The correct order of choices from best to worst is:

The master bedroom, being the primary bedroom, should be the best choice. The family member's bedroom is the next suitable option, and the family room is the least private space among the choices provided.

Answer:

D

Explanation:

Petroleum is one of the top ingredients that makes of gas. When it burns it releases exhaust made of carbon dioxide into the atmospere which has a wide range of effects.

More petroleum would be burned, which would cause the amount of carbon dioxide in the atmosphere to increase. Hence, option D is correct.

Petroleum, also known as crude oil, or simply oil, is a naturally occurring yellowish-black liquid mixture of main hydrocarbons.

Petroleum is one of the top ingredients made of gas. When it burns it releases exhaust made of carbon dioxide into the atmosphere which has a wide range of effects.

Hence, option D is correct.

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Answer:

A + BC → AC + B            Single Replacement

AB + CD → AC + BD       Double Replacement

A + O₂ → AO                   Combustion

AB → A + B                      Decomposition

A + B → AB                       Synthesis  

AC + O₂ → CO₂ + H₂O    Combustion  

Explanation:

So, A + BC → AC + B is an example for single replacement reaction.

Here, A replaces B in the compound BC.

So, AB + CD → AC + BD is an example for double replacement reaction.

Here, A replaces C in the compound CD and B replaces D in the compound CD.

So, A + O₂ → AO and AC + O₂ → CO₂ + H₂O are examples of combustion reactions.

So, AB → A + B is an example for decomposition reactions.

where Ab is decomposed for A and B.

So, A + B → AB is an examples for the synthesis reactions.

This is a three-part question

Answers:

Explanation:

1) Part (a) What is the oxidation number of chlorine in bleach (NaOCl)?

a) Rule one: In a neutral compound the sum of the oxidation states is zero.

Since NaOCl is a neutral compound the sum of the oxidation states of Na, O and Cl is 0.

b) Rule two: since Na is an alkaline metal, its oxidation state is +1

c) Rule three: the most common state of oxygen, except in peroxides, is -2.

Then,

      Sum = +1 - 2 + x = 0 ⇒ x = 2 - 1 = 1

Conclusion: the oxidation state of NaOCl is +1.

2) Part (b) Is this reaction above redox?  

In a redox reaction the oxidation states of some substances increase (get oxidized) and the oxidation states of some substances decrease (get reduced).

The reaction is represented by the chemical equation given:

Since the chlorine gas (Cl₂) is a molecule of only chlorine atoms, its oxidation state is zero, and since chlorine is forming compounds on the right side (NaOCl and NaCl) you can immediately conclude that the oxidation state of chlorine changed, and this is a redox reaction.

In fact:

Therefore, chlorine is being oxidized (its oxidation state increases from 0 to +1) and is also being reduced (its oxidation state is reduced from 0 to -1), and this is a redox reaction.

3) Part (c) What is the percent yield of this reaction?

a) Chemical equation (given)

b) Theoretical mole ratio:

c)  Convert 83.0 g of chlorine gas to moles:

d) Determine the theoretical yiedl using proportions:

e) Convert 0.5195 mol NaOCl to grams:

         That must be rounded to 3 significant figures (such as the mass of belach is given: 22.0 g)

f) Calculate the percent yiled:

B

Atomic mass = no. of proton

Atomic mass= P +N

27= 13+N

N=14

Answer:

14

Explanation:

The atomic # is how many protons it has, the mass is the total number of protons (P) and neutrons (N).

P+N=M     13+N=27

27-13=14    Neutrons= 14

Got it right on the exam

Answer:

Diamond and graphite are allotropes of carbon.

Explanation:

Diamond has a close packed crystal structure which is responsible for its extreme hardness. In it, each carbon atom is sp³ hybridised and bonded to four other carbon atoms in a tetrahedral arrangement. Diamond has a hardness of 10 on mohs scale with a cubic crystal form.

Note: allotropes of an element have different molecular structure.

Graphite on the other hand is made up of layers of hexagonal structure that are weakly bonded by van-der-waals forces. This layered arrangement explains its softness/slippery feeling and hence it is used as a lubricant. In each layer, each carbon atom is sp² hybridised and bonded to three other carbon atoms in a trigonal planar arrangement.

The presence of [tex]\pi[/tex] electrons in the layers accounts for its ability to conduct electricity.

Answer:

5.2 x 10⁻⁴ M.

Explanation:

P = kC

where P is the partial pressure of the gaseous  solute above the solution.

k is a constant (Henry’s constant).

C is the concentration of the dissolved gas.

P₁C₂ = P₂C₁,

P₁ = 1.0 atm, C₁ = 6.8 x 10⁻⁴ mol/L.

P₂ = 0.76 atm, C₂ = ??? mol/L.

∴ C₂ = (P₂C₁)/P₁ = (0.76 atm)(6.8 x 10⁻⁴ mol/L)/(1.0 atm) = 5.168 x 10⁻⁴ mol/L ≅ 5.2 x 10⁻⁴ M.

5.2 × 10⁻⁴ M is the concentration of dissolved nitrogen, if the partial pressure of nitrogen gas in air is 0.76 atm.

Henry's law is proposed for the dissolved gas and it is represented as:

P = kC, where

P = partial pressure

k = henry's constant

C = concentration

And for the given question required equation for concentration is :

P₁/C₁ = P₂/C₂

P₁C₂ = P₂C₁, where

P₁ = given partial pressure of nitrogen = 1atm

C₁ = given concentration of nitrogen = 6.8×10⁻⁴ mole/L

P₂ = partial pressure of nitrogen = 0.76atm

C₂ = required concentration of nitrogen = to find?

On putting all values in the above equation we get,

1atm × C₂ = 0.76atm × 6.8×10⁻⁴ mole/L

C₂ = 5.168 x 10⁻⁴ mol/L = 5.2 × 10⁻⁴ M

Hence, option (1) is correct i.e. 5.2 × 10⁻⁴ M is the concentration of dissolved nitrogen.

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Answer:

[tex]\boxed{\text{11.8 kJ}}[/tex]

Explanation:

The formula for the heat released is

q = mCΔT

Data:

m = 28.9 g

C = 0.385 J·°C⁻¹g⁻¹

T₁ = 1083 °C

T₂ = 25.0 °C

Calculations:

(a)Temperature change

ΔT = T₂ - T₁ = 25.0 - 1083 = -1058 °C

(b) Heat released

q = 28.9 × 0.385 × (-1058) = -11 800 J = -11.8 kJ

The negative sign shows that energy is released, so the copper has released [tex]\boxed{\textbf{11.8 kJ}}[/tex] of energy.

The energy released when a 28.9 gram piece of copper cools from 1083 °C to 25.0 °C is 11771.837 J.

The question asks to calculate the energy released when a 28.9 gram piece of copper is cooled from its melting point of 1083 °C to 25.0 °C. The specific heat of copper is given as 0.385 J/g°C. To find the energy released, we can use the formula: Energy (Q) = mass (m) × specific heat (c) × change in temperature (ΔT).

In this case, ΔT (change in temperature) = final temperature - initial temperature = 25.0 °C - 1083 °C = -1058 °C (since we are cooling down, this is a negative value, indicating heat loss). Thus, the calculation becomes Q = 28.9 g × 0.385 J/g°C × (-1058 °C).

Q = 28.9 × 0.385 × (-1058) = -11771.837 joules

The energy released by the copper as it cools down is 11771.837 (since energy release is typically considered positive, we take the absolute value).

Answer:

Explanation:

Solutions are homogeneous mixtures.

A solution contains at least one solute component and one solvent component all in the same phase.

The term solubility is used to express the maximum amount of solute that can be dissolved in certain amount of solvent, and is measured at a given temperature and pressure.

You may refer to a solution as concentrated or diluted. These are kind of vague terms, in the sense that they do not express how much solute is dissolved. They just tell if there are many dissolved particles (molecules or ions), which is expressed as concentrated, or just a few particle, which is express as diluted.

Other more specific terms used to refer the amount of solute dissolved in a solution are: unsaturated solution, saturated solution, and supersaturated solution.

Unsaturated solution: the solution contains less solute than what it can have. The solution may dissolve more solute.

Saturated solution: the solution has the maximum amount of solute that it can dissolve, at certain temperature and pressure. If you add more solute to a saturated solution, it will not get dissolved (unless you change the temperature or pressure).

Supersaturated solution: a special condition where the solution contains more solute than the saturated solution, at the same temperature and pressure. This is a very unstable situation and any perturbation will make that the excess solute precipitate.

Final answer:

A solution with many dissolved molecules in a fixed amount of solvent is called a concentrated solution, characterized by its large solute-to-solvent ratio and uniform composition.

Explanation:

A solution that contains many dissolved molecules in a fixed amount of solution is called a concentrated solution. This type of solution has a relatively large amount of solute in a given amount of solvent. A solution is a homogeneous mixture of two or more pure substances. In the case of a concentrated solution, the ratio of solute to solvent is greater compared to a dilute solution, which contains a smaller amount of solute relative to the solvent.

The substance present in the larger amount is the solvent, which can dissolve other substances called solutes. During the process of dissolving, the solute particles are evenly distributed throughout the solvent creating a uniform composition. This even distribution makes the resulting solution homogeneous, meaning that the composition is the same throughout. The molarity of a solution refers to its concentration, providing a measure of the number of moles of solute per liter of solution.

Answers:

Explanation:

See each choice:

a. Cl₂

b. K

c. Ag⁺

d. Zn²⁺

In terms of gaining and losing electrons, Cl2 and Ag+ (which gain electrons) are oxidizing agents. K, which loses an electron, is a reducing agent. Zn2+ also gaining electrons, acts also as an oxidizing agent.

In terms of tendencies to lose or gain electrons, a substance that tends to gain electrons and acts in oxidation reactions is called an oxidizing agent. Conversely, a substance that tends to lose electrons and acts in reduction reactions is known as a reducing agent.

Looking at the substances in question: a. Cl2 tends to gain electrons and hence would act as an oxidizing agent. b. K tends to lose an electron, and thus it would be a reducing agent. The c. Ag+ ion would gain an electron to become neutrally charged Ag, making it an oxidizing agent. Lastly, d. Zn2+ can also gain electrons and become neutral, making it an oxidizing agent as well.

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Answer:

Explanation:

4

The acid in this diagram is CH3CH2CH2-COOH. That will turn any litmus to red.

1

I'm not sure I'm reading the question correctly. I think the point is that H2 breaks up and goes on either side of the Double Bond. If that is the case, E is the correct answer. CH3CH2CH2CH3. I'm not totally sure.

2

What is happening here is the equation has progressed to kicking out one of the hydrogens and replacing it with a Br. The other Br and the kicked out Hydrogen combine to form HBr

That means (2) should be C

3

I have no idea what 3 is asking you or telling you to do

I believe your answer would be the 3rd one

Answer:

[tex]Br_{4}Si[/tex] is written incorrectly

Explanation:

In a molecular formula, the central atom in it's lewis structure is written first followed by other bonded atoms.

The least electronegative atom (except H) is the central atom in a lewis structure.

In [tex]Br_{4}Si[/tex], Si is the least electronegative atom as Br has higher electronegativity than Si. Therefore Si is the central atom in lewis structure of [tex]Br_{4}Si[/tex]. So molecular formula of [tex]Br_{4}Si[/tex] should be written as [tex]SiBr_{4}[/tex].

In all other cases, the least electronegative atom have been written first.

So, [tex]Br_{4}Si[/tex] is written incorrectly.

Answer:

option D = 204 Pa

Explanation:

Given data:

Weight of book = 12 N

Area of book =  0.21 m × 0.28 m = 0.0058 m²

Pressure of book = ?

Solution:

formula

pressure = force / area

P = f/ A

now we will put the values in formula,

P = 12 N/ 0.0058  m²

P= 204 Nm⁻²      ( Nm⁻²= Pa)

P = 204 Pa

The correct Answer is option (D). The pressure exerted by the book is approximately 204 Pa.

To find the pressure exerted by the book, we can use the formula for pressure:

[tex]\[ \text{Pressure} = \frac{\text{Force}}{\text{Area}} \][/tex]

First, calculate the area of the back cover:

[tex]\[ \text{Area} = \text{length} \times \text{width} \][/tex]

[tex]\[ \text{Area} = 0.21 \, \text{m} \times 0.28 \, \text{m} \][/tex]

[tex]\[ \text{Area} = 0.0588 \, \text{m}^2 \][/tex]

Now, calculate the pressure:

[tex]\[ \text{Pressure} = \frac{12 \, \text{N}}{0.0588 \, \text{m}^2} \][/tex]

[tex]\[ \text{Pressure} \approx 204.08 \, \text{Pa} \][/tex]

Rounding to the nearest whole number, the pressure exerted by the book is approximately 204 Pa.

Answer:

valence electrons

Explanation:

noble gases like argon or neon don't react easily with other elements because they have completely filled outer valence electron shell, but other elements react easily to try and have a noble gas structure.

Final answer:

Chemical reactivity is the propensity of an element to interact with others to form compounds, and it can be observed in reactions such as synthesis or combination reactions, where elements or compounds unite to form a new substance, following the principle that atoms are neither created nor destroyed.

Explanation:

The tendency of an element to react with other elements to produce compounds is termed reactivity, and it describes elements and compounds that are reactive and will readily react with many other substances. Reactive metals, for example, may form halide compounds with halogens or displace hydrogen from dilute acids.

When looking at chemical reactions, we must consider the starting substances that change. These are typically elements or compounds that combine in a reaction. This combination can yield a more complex compound. An example of this is a synthesis reaction, such as when sodium metal reacts with chlorine gas to form sodium chloride:

2 Na (s) + Cl2 (g) → 2 NaCl (s)

In a broader sense, chemical reactions adhere to the principle that atoms of different elements react with each other in fixed whole-number proportions to create compounds. During these reactions, atoms can separate and recombine to form new substances, but they are never created or destroyed.

Chemists have developed ways to categorize reactions to make predictions about which compounds will react and what products will be formed. Familiarity with basic types of reactions such as combination, decomposition, and displacement reactions is crucial. In the realm of combination reactions, one such reaction is the formation of carbon dioxide from the reaction of carbon monoxide with oxygen:

2CO (g) + O2 (g) → 2CO2 (g)

a) acid-neutral-base

How many acids are shown? 4

How many bases are shown? 7

What range seems to be missing? 5-6

A cabbage indicator will turn red in an acid solution, purple in a neutral solution, and green to yellow in basic solutions. To find out how many acids or bases are shown in a photo, count the number of solutions that have turned red (for acids) or green to yellow (for bases).

Unfortunately, without the specific photo referenced in the question, it's impossible to provide an exact order of the solutions. However, I can explain how to determine if a solution is an acid or base using a cabbage indicator. When a cabbage indicator is added to different solutions, it changes colors based on the pH level of the solution. In acidic solutions, the cabbage indicator turns red, while it turns green to yellow in basic solutions. The neutral solution will have a purple color.

To find out how many acids or bases are shown in the photo, you would count how many of the solutions turn red (for acids) or green to yellow (for bases).

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Answer:

[tex]\boxed{\text{52 840 mol}}[/tex]

Explanation:

Since you have the volume of the gas at STP, we can use the Ideal Gas Law to calculate the number of moles. The identity of the gas doesn't matter.

pV = nRT

n = (pV)/(RT)

Data:

p = 1 bar

V = 1200 m³ = 1.2 × 10⁶ dm³

R = 0.083 14 bar·dm³K⁻¹mol⁻¹

T = 273.15 K

Calculation:

n = (1 bar × 1.2 ×10⁶ dm³)/(0.083 14 bar·dm³K⁻¹mol⁻¹ × 273.15 K)

= 52 840 mol

The power plant releases [tex]\boxed{\text{52 840 mol of SO}_{2}}[/tex].

Answer:

[tex]\boxed{3 \times 10^{23}}[/tex]

Explanation:

1 mol of helium contains 6.022 × 10²³ atoms

[tex]\text{Atoms of He} =\text{0.5 mol He} \times \dfrac{ 6.022 \times 10^{23} \text{ atoms He}}{\text{1 mol He}}= 3 \times 10^{23} \text{ atoms He}[/tex]

The balloon contains [tex]\boxed{3 \times 10^{23} \text{ atoms of He}}[/tex].

69.253 helium particles are in the balloon.

Helium is composed of two electrons bound by the electromagnetic force to a nucleus containing two protons along with either one or two neutrons, depending on the isotope, held together by the strong force. Unlike for hydrogen, a closed-form solution to the Schrodinger equation for the helium atom has not been found.

A helium atom is an atom of the chemical element helium. Helium is composed of two electrons bound by the electromagnetic force to a nucleus containing two protons along with either one or two neutrons, depending on the isotope, held together by the strong force. Unlike for hydrogen, a closed-form solution.

Helium is the element which you can find on the upper right side of the periodic table with atomic number 2. It comes first amongst the family of the noble gases. Helium falls under inert gas since its outermost electron orbital is full with two electrons.

The answer is 69.253.

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Answer:

2.4 kPa.

Explanation:

According to Dalton's law: the total pressure of an ideal gas mixture is equal to the sum of the partial pressures of the gases in the mixture.

Ptotal = P of O₂ + P of N₂ + P of CO₂.

where, Ptotal is the total pressure = 32.0 kPa,

P of O₂ is partial pressure of oxygen gas = 6.6 kPa,

P of N₂ is the partial pressure of nitrogen gas = 23.0 kPa,

P of CO₂ is the partial pressure of carbon dioxide gas = ??? kPa.

∵ Ptotal = P of O₂ + P of N₂ + P of CO₂.

∴ 32.0 kPa = 6.6 kPa + 23.0 kPa + P of CO₂.

∴ P of CO₂ = 32.0 kPa - (6.6 kPa + 23.0 kPa) = 2.4 kPa.

Final answer:

pH is a measure of how acidic or basic a solution is, based on the hydrogen ion concentration. The pH scale ranges from 0 to 14, where values below 7 are acidic and above 7 are basic. It is calculated as the negative logarithm of the hydrogen ion concentration.

Explanation:

Understanding pH

What is pH? pH is a measure that indicates the acidity or basicity (alkalinity) of a solution. It is a scaled value ranging from 0 to 14 where:

A pH of 7 is considered neutral; neither acidic nor basic.

Values below 7 indicate an acidic solution with a higher concentration of hydrogen ions (H+).

Values above 7 indicate a basic solution with a lower concentration of hydrogen ions.

The pH is calculated as the negative, base-10 logarithm of the hydrogen ion concentration in the solution. A lower pH number means a higher concentration of hydrogen ions and therefore a more acidic solution. Conversely, a higher pH means a lower concentration of hydrogen ions and a more basic solution. The pH scale is a concise way to represent the hydrogen ion concentration, which varies markedly among different solutions and affects their properties.

Answer:

A) Energy is needed to start photosynthesis and is a product of cellular respiration.

Explanation:

Answer: A). Energy is needed to start photosynthesis and is a product of cellular respiration.

Explanation:

Energy in the form of sunlight is absorbed by the plants so as to prepare their food (carbohydrates)in the process of photosynthesis.

The energy is produced in the process of cellular respiration. The cellular respiration involves the break down of glucose molecules in the food in the form of energy currencies called as ATP (Adenosine triphosphate) molecules. This form of energy is required for regulating cellular metabolism and vital functions.

Answer:

worldwide burning of fossil fuels

Explanation:

The heavy usage of the fossil fuels as energy sources for the industry has resulted in much increased emissions of CO2 in the atmosphere. It all started around 200 years ago with the Industrial Revolution. In order for the machines to function, efficient energy sources were needed, and the best thing at that time for that was the coal. Through the burning, the coal manages to release enormous amounts of CO2 into the atmosphere. After some time, the oil was discovered as well, and it started to be heavily used as well, further increasing the CO2 emissions. As the technology has been developing more and more, the demand for the usage of the fossil fuels has been increasing constantly, so there's an ever growing CO2 emissions into the atmosphere.