plants take in carbon dioxide from the air through holes in the

a. xylem

b. spongy layer

c. palisade layer

d. vascular bundle

Answers

Answer 1

Answer:

c. palisade layer  


Related Questions

What is the molecular formula for ammonium nitrate?

Answers

NH4NO3 is the molecular formula

Final answer:

The molecular formula for ammonium nitrate is NH4NO3. It is a salt derived from the reaction of ammonia (NH3) and nitric acid (HNO3), resulting in the formation of the ammonium ion (NH4+) and the nitrate ion (NO3-).

Explanation:

The molecular formula for ammonium nitrate is NH4NO3. This compound is a salt of ammonia (NH3) and nitric acid (HNO3). The formula can be deduced from the process by which it is formed: The ammonia molecule's nitrogen atom (N) combines with three hydrogen atoms (H) to form NH3, and the nitric acid molecule's nitrogen (N) combines with one hydrogen (H), one nitrogen (N), and three oxygen (O) atoms to form HNO3.

In a reaction between these two compounds, the hydrogen in the nitric acid becomes attached to the nitrogen in the ammonia, forming the ammonium ion (NH4+), and the remaining NO3 molecule forms the nitrate ion (NO3-). These two ions come together to form ammonium nitrate.

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Which year was DNA evidence introduced?

1908

1988

1980

1998


Answers

1988 was when it was first introduced

Final answer:

DNA evidence was first introduced in 1988 and has since revolutionized forensic science. Its discovery by Miescher in 1869 and subsequent research paved the way for its pivotal role in modern biology and criminal justice.

Explanation:

DNA evidence was first introduced in 1988. This introduction of DNA for forensic purposes marked a monumental advancement in the field of criminal investigations and legal proceedings. The science of DNA was discovered by Friedrich Miescher in 1869, and significant developments unfolded over the years, leading to our contemporary understanding of DNA as the genetic material responsible for heredity. Experiments by scientists such as Oswald Avery, Colin MacLeod, and Maclyn McCarty in the 1940s, and the discovery of the 3D-double-helix structure by James Watson and Francis Crick in 1953, set the stage for the many applications of DNA science we see today, including forensic analysis.

Which describes the role of energy in photosynthesis and cellular respiration?


A) Energy is needed to start photosynthesis and is a product of cellular respiration. B)Without light energy, photosynthesis and cellular respiration cannot occur. C)Energy is both a reactant and product in photosynthesis and in cellular respiration.

Answers

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.

Balance the following redox equation using the oxidation-number-change method. Show your work, describing each step.
HNO3 + H2S —-> S + NO + H2O

Answers

2HNO3+3H2S ——>2S+4H2O+2NO

The coefficients in a chemical equation represent the

Answers

Answer:

The coefficients in a chemical equation represent the relative number of moles of each reactant and product that interven in the chemical reaction.

Explanation:

The coefficients are the numbers that you put in front of each chemical formula that represents the reactants and products in the chemical equation. They indicate the mole ratio in which the elements or compounds react to form the products, as per the chemical equation.

See an example:

Word equation: hydrogen and oxygen produce water

Chemical (skeleton) equation: H₂ (g) + O₂(g) → H₂O (g)

      This equation is not balanced: the  number of atoms of oxygenin the reactant side is 2 while the number of atoms of oxygen isn the product side is 1. In order to balance the equation you need to add some coefficients.

When no coefficients are shown it is understood that the coefficient is 1.

Balanced chemical equation: 2H₂ (g) + O₂(g) → 2H₂O (g)

The coefficients 2 in front of H₂ and 1 (understood) in front of O₂, in the reactant side, and 2 in front of H₂O, in the product side, balance the equation.

Those coefficients mean that the 2 molecules (or mole of molecules) of H₂ react with 1 molecule (or mole of molecules) of O₂ to form 2 molecules (or moles) of H₂O (product side).

That is the mole ratio: 2 H₂ : 1 O₂ : 2 H₂O.

Notice that, in spite of the aboslute numbers may change, the mole ratio is unique for any chemical reaction.  For example 4 : 2 : 4 is the same ratio that 2 : 1 : 2, or 8 : 4 : 8, but the most common practice is to use the most simple form of the ratio, i.e. 2: 1: 2.

The representation that coefficients that are found in a chemical equation provide, is :  number of moles that is present in the reactants as well as products.

The coefficients of the equation helps to know the  number of moles that is present in reactants as well as  products in a balanced equation.

If the equation is not balanced, then it needs to be balanced first, with information of the  coefficients, it is possible to calculate components of reactants as well as the products that is taking part in the chemical reaction.

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Which reaction model represents a nuclear fission reaction?

A → B + C
n + A → B + C + n
A + C → B + n
A → B + C + n

Answers

Answer: option B

Explanation: since nuclear fission involves the decay of larger nuclide into smaller nuclei along with Neutron when it is collide with Neutron.

Example Decay of U-235 into Kr and Ba along with 3 neutrons

Answer:

By presuming n denotes neutron, A is an atom and B & C are lighter nuclei, a reaction model of nuclear fission can be represented as follows:

n + A → B + C + n

Explanation:

A nuclear fission reaction is a process where a neuron collide with an atom and split it into two lighter nuclei and at the same time, a neuron and a large amount of energy will be released. The released neuron will then induce another nuclear fission on the next atom and repeat the same reaction process.

The understanding of nuclear fission play an important role in developing nuclear energy technology.

Hello! I need help with this question asap please! ;-;

Match the following chemical reactions: A, B, C, and D are elements.

A + BC ---- AC + B Combustion
AB + BD --- AC + BD Synthesis
A + O2 - AO Combustion
AB -- A + B Single Replacement
A + B - AB Double Replacement
AC + O2 - CO2 + H2O Decomposition

Answers

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:

Single replacement is a type of chemical reaction where an element reacts with a compound and takes the place of another element in that compound.

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

Here, A replaces B in the compound BC.

Double Replacement is a type of chemical reaction where two compounds react, and the positive ions (cation) and the negative ions (anion) of the two reactants switch places, forming two new compounds or products.

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.

Combustion reactions always involve molecular oxygen O₂. Anytime anything burns (in the usual sense), it is a combustion reaction. Combustion reactions are almost always exothermic (i.e., they give off heat).

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

Decomposition reactions is a type of chemical reaction in which a single compound breaks down into two or more elements or new compounds. These reactions often involve an energy source such as heat, light, or electricity that breaks apart the bonds of compounds.

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

where Ab is decomposed for A and B.

Synthesis   is a type of reaction in which multiple reactants combine to form a single product. Synthesis reactions release energy in the form of heat and light, so they are exothermic.

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

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

Answers

Answer:

14.434 r.a.m.

Explanation:

The atomic mass of an element is a weighted average of its isotopes in which the sum of the abundance of each isotope is equal to 1 or 100%.

∵ The atomic mass of N = ∑(atomic mass of each isotope)(its abundance)

∴ The atomic mass of N = (atomic mass of N-14)(abundance of N-14) + (atomic mass of N-16)(abundance of N-16)

atomic mass of N-14 = 14.0 r.a.m, abundance of N-14 = percent of N-14/100 = 78.3/100 = 0.783.

atomic mass of N-16 = 16.0 r.a.m, abundance of N-16 = percent of N-16/100 = 21.7/100 = 0.217.

∴ The atomic mass of N = (atomic mass of N-14)(abundance of N-14) + (atomic mass of N-16)(abundance of N-16) = (14.0 r.a.m)(0.783) + (16.0 r.a.m)(0.217) = 14.434 r.a.m.

Carbon-14 emits beta radiation and decays with a half-life (t ) of 5730 years. Assume that you start with a mass of 6.00 × 10^–12 g of carbon 14. How many grams of the isotope remains at the end of three half-lives?

Answers

Answer:

did you ever find the answer

Explanation:

Answer: [tex]0.75\times 10^{-12}[/tex]

Explanation:

Formula used :

[tex]a=\frac{a_o}{2^n}[/tex]

where,

a = amount of reactant left after n-half lives = ?

[tex]a_o[/tex] = Initial amount of the reactant = [tex]6\times 10^{-12} g[/tex]

n = number of half lives = 3

Putting values in above equation, we get:

[tex]a=\frac{6\times 10^{-12} }{2^3}[/tex]

[tex]a=\frac{6\times 10^{-12} }{8}[/tex]

[tex]a=0.75\times 10^{-12}[/tex]

Therefore, the amount of carbon-14 left after 3 half lives will be [tex]0.75\times 10^{-12}g[/tex]

What is the name of the molecule shown? Will give brainliest if its right.
Please and thank you.

A. 2,2-dimethylpropane
B. Trimethylethane
C. 3-dipropane
D. Pentane

Answers

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

Select the correct answer. In which state of matter do molecules have the lowest kinetic energy? A. liquid state B. plasma state C. gaseous state D. solid state

Answers

Answer:

D. Solid state

Explanation:

In solid state the particles of  a substance, vibrate in fixed positions though they posses less kinetic energy. This is the reason as to why the particles do not move far apart from each other making the solids remain in fixed shapes unless an extra energy is added.

Since solids cannot move and can only fluctuate around their mean position, they have the lowest kinetic energy. Despite the fact that liquids have more kinetic energy than solids. Here the correct option is D.

Solids are composed of the least energy particles. They are packed close together, giving them little room to maneuver. The energy of a gas's particles is the highest, with a liquid's particles having higher energy than a solid's.

A pure substance has more energy in its gaseous state than it does in its liquid state, which has more energy than it does in its solid state. When particles are in a gaseous form, their kinetic energy is at its maximum.

Thus the correct option is D.

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A solution that contains many dissolved molecules in a fixed amount of solution is called

Answers

Answer:

A solution that contains many dissolved molecules in a fixed amount of solution is called concentrated.

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.

How do you do question 1-4?

Answers

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

Blaise Pascal discovered that changes in pressure _____.

A. will decrease with depth of fluid

B. will increase with depth of fluid

C. will depend on the area

D. are transmitted equally through a fluid

Answers

Answer:

D. are transmitted equally through a fluid

Explanation:

Blaise Pascal discovered the Pascal's principle which states that the pressure applied to a fluid at a point inside a closed system will be transmitted equally in all directions through out the fluid.Pascal's principle has a wide range of application, for example in hydraulics such as car brakes which is the most used hydraulic system. The fluid used must be in compressible.

A train approaching a crossing changes speed from 10 m/s to 25 m/s in 240 s. How can the train's acceleration be described?

Answers

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]

If you obtained 2.50 moles of CuSO4 from the reaction of CuO and H2SO4, but the theoretical yield was 3.19 moles, what was the percent yield?

Answers

Answer:

78.4%

Explanation:

Just as context, write the chemical equation and the mole ratios

1) Balanced chemical equation:

CuO (s) +  H₂SO₄ (aq) → CuSO₄ (aq) + H₂O (l)

2) Therotetical (stoichiometric) mole ratios:

1 mol CuO : 1 mol  H₂SO₄  : 1 mol CuSO₄  : 1 mol H₂O

You can calculate the percent yield from the amount of CuSO₄ obtained and the theoretical yield

3) Percent yield

Definition:

         Percent yield = (actual yield / theoretical yield)×100

Theoretical yiedl (given): 3.19 moles CuSO₄

Actual yield (given): 2.50 moles CuSO₄

Calcualtion:

Substitute the values in the formula:

Percent yield = (2.50 moles CuSO₄ / 3.19 moles CuSO₄)×100 = 78.4%

What would most likely occur if the number of cars being driven increased worldwide?

A. More coal would be burned, which would cause the amount of carbon dioxide in the atmosphere to increase.
B. More petroleum would be burned, which would cause the amount of carbon dioxide in the atmosphere to decrease.
C. More coal would be burned, which would cause the amount of carbon dioxide in the atmosphere to decrease.
D. More petroleum would be burned, which would cause the amount of carbon dioxide in the atmosphere to increase.

Answers

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.

What is petroleum?

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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How do you do this problem?

Answers

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

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The mass of cobalt-60 in a sample decreased from 0.800g to 0.200g over a period of 10.5 years. From this information, calculate the half-life of cobalt-60.

Answers

Final answer:

The half-life of cobalt-60, based on the provided information and the calculation method where the sample mass decreases to a quarter over two half-lives (10.5 years), is confirmed to be 5.27 years. This example illustrates how the half-life concept helps in understanding the decay rate of radioactive isotopes.

Explanation:

To calculate the half-life of cobalt-60 given that the mass of a cobalt-60 sample decreased from 0.800g to 0.200g over a period of 10.5 years, we use the concept of half-lives. The question implies that the sample underwent two half-lives for its mass to decrease to 0.200g from 0.800g.

Here's why: after one half-life, the mass would decrease to 0.400g (half of 0.800g), and after another half-life, it would decrease to 0.200g (half of 0.400g), totaling a decrease over two half-lives.

Given the provided information that the half-life of cobalt-60 is 5.27 years, this aligns perfectly with our calculation method. After 10.54 years (which is approximately the given time span of 10.5 years), two half-lives would have passed, confirming the half-life of cobalt-60 as 5.27 years.

This demonstrates a practical application of understanding radioactive decay and the significance of half-life in measuring how quickly unstable isotopes decline to half their original amount.

When a metal is heated in a flame, the flame has a distinctive color. This information was eventually extended to the study of stars because a red shift in star color indicates stars are moving away. star color indicates the distance from the earth. the line spectra of stars indicate which elements are present. it allows the observer to determine the size of stars.

Answers

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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What heavier element is created when hydrogen atoms fuse together in the sun’s core?

Answers

Answer:

Helium is created from hydrogen in the sun's core.

Four hydrogen-1 nuclei fuse to produce

one helium-4 nucleus, two neutrons, two positrons, and two electron neutrinos.

Explanation:

Step One:

[tex]{\rm ^1_1 H + ^1_1 H\to ^2_1 H + e^{+}} + v_e[/tex].

Two hydrogen-1 nuclei fuse. One proton will convert to a neutron. The products will be

one hydrogen-2 nucleus, one positron, andone electron neutrino.

Step Two:

[tex]\rm ^1_1 H +^2_1 H \to ^3_2 He[/tex].

There are plenty of hydrogen-1 nuclei available in the core of the sun. The hydrogen-2 nucleus from step one will fuse with a hydrogen-1 nucleus. The product is

one helium-3 nucleus.

Step Three

[tex]\rm ^3_2 He + ^3_2 He \to ^4_2 He + ^1_1 H + ^1_1 H[/tex].

Two helium-3 nuclei from step two react with each other. The products are:

one helium-4 nucleus, andtwo hydrogen-1 nuclei.

The overall reaction will be:

[tex]{\rm 6\; ^1_1 H \to ^4_2 He + 2\; ^1_1 H+2\; e^{+}}+v_\text{e}[/tex].

[tex]{\rm 4\; ^1_1 H \to ^4_2 He + 2\; e^{+}} + v_\text{e}[/tex]

In other words, hydrogen nuclei in the core of the sun fuse together to form helium.

Two students are playing tug of war. If Student A is pulling the rope with 6N of force and Student B is pulling the rope with 9N of force, what is the net force

Answers

Answer:

3

Explanation:

An atom of aluminum (Al) has an atomic number of 13 and a mass number of 27. How many neutrons does it have?

A) 13
B) 14
C) 27
D) 40

Answers

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

What is the molarity of a solution containing 100 moles of NaCl dissolved in 10 liters of water?

2 mol/L

10 mol/L

0.5 mol/L

5 mol/L

Answers

Answer:

10 mol/L

Explanation:

Molarity or concentration is given by the formula;

Molarity = Number of moles/Volume in Liters

In this case; number of moles = 100 and Volume = 10 L

Therefore;

Molarity = 100 moles/10 L

             = 10 mol/L

The answer is 10 mol/L

Sedimentary rocks found high in the Himalayan Mountains have been found with fossils of clams and other marine life. What does this indicate about the origin of the Himalayan Mountains? A) There was once a large ocean at top of the mountains. B) Animals that now live on the mountains once lived under water. C) The Earth's crust that formed these mountains was once covered with an ocean. D) Continental drift resulted two tectonic moving closer to each other over time.

Answers

Answer:

c

Explanation:

usa test prep

A beaker containing 80 grams of lead(ii) nitrate, pb(no3)2, in 100 grams of water has a temperature of 30 ºc. approximately how many grams of the salt are undissolved, on the bottom of the beaker?

Answers

Answer:

14 g.

Explanation:

From the figure attached:

the solubility of lead(II) nitrate, Pb(NO₃)₂, in 100 grams of water has a temperature of 30ºC is (66 g).

When beaker containing 80 grams of lead(II) nitrate, Pb(NO₃)₂, in 100 grams of water has a temperature of 30ºC.

∴ The grams of the salt are undissolved, on the bottom of the beaker are (14 g).

80 grams of lead(II) nitrate in 100 grams of water at 30ºC results in 66 grams (option c) of undissolved lead(II) nitrate.

To solve this problem, we need to know the solubility of lead(II) nitrate (Pb(NO₃)₂) in water at 30 ºC.

The solubility of Pb(NO₃)₂ in water at 30 ºC is approximately 122 g/100 mL.

Since we have 100 grams of water, we can calculate the maximum amount of Pb(NO₃)₂ that can dissolve:

Maximum soluble Pb(NO₃)₂ = 122 g/100 mL × 100 g / 1000 mL = 12.2 g

We started with 80 grams of Pb(NO₃)₂, so the amount of undissolved salt is:

Undissolved Pb(NO₃)₂ = 80 g - 12.2 g = 67.8 g ≈ 66g

Therefore, approximately 66 grams of lead(II) nitrate remain undissolved at the bottom of the beaker.

Complete Question - A beaker containing 80 grams of lead(II) nitrate, Pb(NO₃)₂, in 100 grams of water has a temperature of 30 ºC. Approximately how many grams of the salt are undissolved, on the bottom of the beaker?

a) 20 grams

b) 80 grams

c) 66 grams

d) 14 grams

Which system does not allow for matter or energy to be exchanged outside the system?

Isolated systems

Open system

All systems

Closed system

Answers

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.

What is isolated system ?

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

What is Open system ?

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

What is Closed system ?

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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The solubility of nitrogen gas at 25 degrees C and 1 atm is 6.8 x 10^(-4) mol/L. If the partial pressure of nitrogen gas in air is 0.76 atm, what is the concentration (molarity) of dissolved nitrogen?

5.2 x 10^(-4) M
1.1 x 10^(-5) M
4.9 x 10^(-4) M
3.8 x 10^(-4) M
6.8 x 10^(-4) M

Answers

Answer:

5.2 x 10⁻⁴ M.

Explanation:

The relationship between gas pressure and the  concentration of dissolved gas is given by  Henry’s law:

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.

At two different pressures, there is two different concentrations of dissolved gases and is expressed in a relation as:

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.

What is Henry's Law?

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.

To know more about henry's law, visit the below link:

https://brainly.com/question/7007748

Unless it hits something, a bullet fired towards the sky experiences a constant rate deceleration as soon as it is fired from a gun.
True False

Answers

FALSE

Got it right on the exam

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 .385 j/g c

Answers

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).

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