Learning Task 4: Think of two animals that reproduce sexually. In the first
box, draw an animal that fertilization occurs inside the body. In the second
box, draw an animal that exhibits external fertilization.

please help for me​

Explanation:

How many neutrons are there in the nucleus of arsenic?42 neutrons

The nucleus consists of 33 protons (red) and 42 neutrons (blue).

There are 0.6 moles of sodium chloride in a 250 mL solution with a molarity of 2.4 M sodium chloride.

This leads us to the conclusion that a 250 mL solution of a 0.5 M sodium chloride contains 0.125 moles and 7.32 grammes of sodium chloride, respectively.

A solution with a concentration of 0.4 M contains 0.4 moles of solute per litre of solution. By utilising dimensional analysis, you may calculate how many moles of solute are present in 250 mL of the solution. litre and millilitre units

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When you increase the amount of carbon dioxide in the atmosphere, you also increase the amount of carbonic acid in the ocean.

Carbon dioxide is absorbed from the atmosphere into the ocean through a process called "oceanic uptake," which is facilitated by the exchange of gases at the air-sea interface.

As more carbon dioxide is emitted into the atmosphere, the concentration of carbon dioxide in the ocean increases, leading to a phenomenon called "ocean acidification".

Ocean acidification can have a number of negative impacts on marine organisms, including reduced growth rates and weakened shells or skeletons.

Thus, we can conclude this increases the amount of carbonic acid in ocean.

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The pOH of the 0.001 M NaOH solution is approximately 3.

To determine the pOH of a solution, we need to know the concentration of hydroxide ions (OH-) in the solution.

In the case of a 0.001 M NaOH solution, we can assume that all of the NaOH dissociates completely in water to form Na+ and OH- ions. Therefore, the concentration of hydroxide ions in the solution is also 0.001 M.

The pOH is calculated using the equation:

pOH = -log[OH-]

Substituting the concentration of hydroxide ions, we have:

pOH = -log(0.001)

Using a calculator, we can evaluate the logarithm:

pOH ≈ 3

Therefore, the pOH of the 0.001 M NaOH solution is approximately 3.

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12.9 Theoretical Yield and Percent Yield

FlexBooks® 2.0  >  CK-12 Chemistry For High School  >  Theoretical Yield and Percent Yield

It is best to have high yields for chemical reactions

Can we save some money?

The world of pharmaceutical production is an expensive one. Many drugs have several steps in their synthesis and use costly chemicals. A great deal of research takes place to develop better ways to make drugs faster and more efficiently. Studying how much of a compound is produced in any given reaction is an important part of cost control.

Percent Yield

Chemical reactions in the real world don’t always go exactly as planned on paper. In the course of an experiment, many things will contribute to the formation of less product than would be predicted. Besides spills and other experimental errors, there are usually losses due to an incomplete reaction, undesirable side reactions, etc. Chemists need a measurement that indicates how successful a reaction has been. This measurement is called the percent yield.

To compute the percent yield, it is first necessary to determine how much of the product should be formed based on stoichiometry. This is called the theoretical yield, the maximum amount of product that could be formed from the given amounts of reactants. The actual yield is the amount of product that is actually formed when the reaction is carried out in the laboratory. The percent yield is the ratio of the actual yield to the theoretical yield, expressed as a percentage.

Percent yield is very important in the manufacture of products. Much time and money is spent improving the percent yield for chemical production. When complex chemicals are synthesized by many different reactions, one step with a low percent yield can quickly cause a large waste of reactants and unnecessary expense.

Typically, percent yields are understandably less than 100% because of the reasons indicated earlier. However, percent yields greater than 100% are possible if the measured product of the reaction contains impurities that cause its mass to be greater than it actually would be if the product was pure. When a chemist synthesizes a desired chemical, he or she is always careful to purify the products of the reaction.

Sample Problem: Calculating the Theoretical Yield and the Percent Yield

Potassium chlorate decomposes upon slight heating in the presence of a catalyst according to the reaction below:

In a certain experiment, 40.0 g KClO3 is heated until it completely decomposes. What is the theoretical yield of oxygen gas? The experiment is performed and the oxygen gas is collected and its mass is found to be 14.9 g. What is the percent yield for the reaction?

First, we will calculate the theoretical yield based on the stoichiometry.

Step 1: List the known quantities and plan the problem.

Known

given: mass of KClO3 = 40.0 g

molar mass KClO3 = 122.55 g/mol

molar mass O2 = 32.00 g/mol

Unknown

theoretical yield O2 = ? g

Apply stoichiometry to convert from the mass of a reactant to the mass of a product:

Step 2: Solve.

The theoretical yield of O2 is 15.7 g.

Step 3: Think about your result.

The mass of oxygen gas must be less than the 40.0 g of potassium chlorate that was decomposed.

Now, we use the actual yield and the theoretical yield to calculate the percent yield.

Step 1: List the known quantities and plan the problem.

Known

Actual yield = 14.9 g

Theoretical yield = 15.7 g (from Part 12.11A)

Unknown

Percent yield = ? %

Use the percent yield equation above.

Step 2: Solve.

Step 3: Think about your result.

Since the actual yield is slightly less than the theoretical yield, the percent yield is just under 100%.

Summary

Theoretical yield is calculated based on the stoichiometry of the chemical equation.

The actual yield is experimentally determined.

The percent yield is determined by calculating the ratio of actual yield/theoretical yield.

Review

What do we need in order to calculate theoretical yield?

If I spill some of the product before I weigh it, how will that affect the actual yield?

How will spilling some of the product affect the percent yield?

I make a product and weigh it before it is dry. How will that affect the actual yield?

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Explanation:

Answer:

D) The enthalpy change for a reaction equals the sum of the enthalpy changes of each of its steps.

Explanation:

Hess's Law explains that the enthalpy of a chemical reaction can be expressed as the sum of the enthalpies of the partial reactions that can occur to reach the main reaction.

For example, the sum of the previuos exercise:

Exothermic refers to chemical interactions that aerobic respiration. Combustion reactions release higher energy. Endothermic refers to atoms and molecules that either use or absorb reactive power.

A chemical process known as an endothermic releases energy as heat or light. It is an endothermic reaction's opposite. Chemical equation expressed as reactants + products + energy. An reaction mechanism is one in which electricity is given off as light or warmth.

A response is deemed to be exothermic if it produces heat while also undergoing a net decrease in basic enthalpy change. Samples include those type of combustion, iron rust, including water froze. Exothermic processes are those that discharge heat and energy into the surroundings.

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The answer responses to  the structures shown in the diagram are:

A. chromosomes

C. They would be the same.

B. They are in pairs because each one comes from a different parent.

The chromosomes are in pairs because humans have a diploid number of chromosomes, meaning they have two sets of chromosomes, one inherited from each parent.

The nucleus is important in eukaryotic cells and has many important parts that help the cell work properly. There are some parts inside cells called the nuclear membrane, nucleoplasm, nucleolus, and chromatin. Chromatin is made up of DNA and other proteins.

Every part of a person's body has the same genes, but the way they are organized can be different in different types of cells. The chromosomes in our skin cells might not be the same as the chromosomes in our muscle cells, even if they come from the same person.

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Identify the structures shown.

A. chromosomes

B. mitochondria

C. nuclei

D. vacuoles

C

Describe how the structures from this cell would compare to the structures in the nucleus of another body cell from the same person.

A. There would be longer.

B. They would be shorter.

C. They would be the same.

D. They would be different.

Describe how the structures from this cell would compare to the structures in the nucleus of another body cell from the same person.

A. There would be longer.

B. They would be shorter.

C. They would be the same.

D. They would be different.

Explain why the structures are in pairs.

A. They aren't in pairs.

B. They are in pairs because each one comes from a different parent.

C. This cell is making a copy of itself.

D. The cell always has 2 copies in case 1 is damaged.

Answer:

protons are red neutrons are green electrons are yellow

Explanation:

TIE FIGHTERS GO ZOOOOOM

Burning is a chemical reaction between fuel and oxygen (or other oxidizing agents) in which heat and light energy are produced.

This process is also known as combustion. Combustion is a chemical reaction between a fuel and an oxidant (usually oxygen) that produces heat and light, along with various reaction products, such as carbon dioxide, water vapor, and other gases.

The fuel and oxygen react to form new chemical compounds, releasing energy in the form of heat and light. The chemical equation for burning typically involves the fuel and oxygen reacting to form carbon dioxide and water vapor, as well as other combustion products depending on the type of fuel being burned.

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Answer:

2HCl(aq)+Ca(OH)2(aq)---------->2H2O(I)+ CaCl2(aq)

Strong acids;

H2SO4, HF, HClO4, HI, HBr, HNO3, HCl

Weak acids;

CH3COOH, HNO2, HCN, HCOOH

Strong bases;

LiOH, NaOH, Ca(OH)2, CsOH, Ba(OH)2, KOH

Weak bases;

NH3, (CH3)2NH, CH3NH2

A. KNO3

B. Ca(NO3)2

C. CaCl2

D. KCl

Explanation:

A strong acid/base is such an acid/base that dissociates completely in solution. This means that such acid/base achieves a nearly 100% ionization ability in solution.

A weak base or weak acid ionizes only to a small extent in solution.

The reaction between an acid and a base yields a salt. The corresponding salt in each of the reactions above were shown in the answer.

Answer:

D

Explanation:

The ratio of C6H12O6 (which will be referred to as "the carb") to oxygen is 1 to 6, so if we find an answer which has the same ratio, it should be chosen. A is 1:3
B is even worse with a ratio of the carb to oxygen of 1:2
C is the same as B, 1:2
D has a ratio of the carb to oxygen of 1:6, which is what we are looking for.

Answer:

What are the options?

Explanation:

......

Answer: 4.88 g/mol. and helium

Explanation:

To find the molar mass of the gas, we can use the ideal gas law equation which is PV=nRT where:

P = pressure = 2.000 atm

V = volume = 50.00 L

n = number of moles

R = gas constant = 0.08206 L·atm/K·mol

T = temperature = 273.15 K

First, we need to find the number of moles of the gas:

PV = nRT

n = PV/RT

n = (2.000 atm)(50.00 L)/(0.08206 L·atm/K·mol)(273.15 K)

n = 1.844 mol

Now, we can find the molar mass of the gas by dividing its mass by the number of moles:

molar mass = mass/number of moles

mass = 9.00 g

molar mass = 9.00 g/1.844 mol

molar mass = 4.88 g/mol

Therefore, the molar mass of the gas is 4.88 g/mol.

To determine what gas this is, we can compare the molar mass of the gas to the molar masses of known gases. The molar mass of 4.88 g/mol is closest to that of helium (4.00 g/mol). Therefore, this gas is most likely helium.

Answer:

I think carbon dioxide is

Answer: :)

The temperature of a gas is directly proportional to the average kinetic energy of the particles of the gas. But the total kinetic energy of the molecules of a gas is a measure of the internal energy or thermal energy of the gas.

Explanation:

Given that:

The first step is to determine the vapor pressure at the final temperature of 251K by using the Clausius-Clapeyron equation. This is following by using the ideal gas equation to determine the numbers of moles of butane gas. After that, the mass of butane present in the liquid is determined by using the relation for the number of moles.

Using Clausius-Clapeyron Equation:

\(\mathbf{In (\dfrac{P_2}{P_1} )= -\dfrac{\Delta H_{vap}}{R}(\dfrac{1}{T_2} - \dfrac{1}{T_1})}\)

where;

P1 and P2 correspond to the temperature at T1 and T2.

∴

replacing the values into the given equation, we have;

\(\mathbf{In \dfrac{P_2}{1\ atm} = -\dfrac{22440 \ J/mol}{8.314 \ J/mol.K}(\dfrac{1}{251 \ K} - \dfrac{1}{272.6 \ K})}\)

\(\mathbf{In \dfrac{P_2}{1\ atm} =-(0.852053785)}\)

\(\mathbf{P_2=0.427 \ atm}\)

As such, at -22° C; the vapor pressure = 0.427 atm

Now, using the ideal gas equation:

PV = nRT

where:

∴

Making (n) the subject of the formula:

\(\mathbf{n = \dfrac{PV}{RT}}\)

\(\mathbf{n = \dfrac{0.427 atm \times 0.250 L}{(0.08206 \ L.atm/k.mol) \times 251}}\)

\(\mathbf{n =0.00518 mol}\)

We all know that the standard molecular weight of butane = 58.12 g/mol

∴

Using the relation for the number of moles which is:

\(\mathbf{number \ of \ moles = \dfrac{mass}{molar mass}}\)

mass = 0.00518 mole × 58.12 g/mol

mass = 0.301 g

∴

The mass of butane in the flask = 0.301 g

But the mass of the butane present as a liquid in the flask is

= 0.8 g - 0.301 g

= 0.499 g

In conclusion, the mass of the butane present as a liquid in the flask is 0.499 g

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Option C is the correct set of the problem for mass of water produced by 3.2 moles of oxygen and an excess ethene.

Ethene (C2H4) burns in the presence of oxygen (O2) to form carbon dioxide (CO2) and water (H2O) along with the evolution of heat and light.

C₂H₄  + 3O₂   ----- > 2CO₂ + 2H₂O

from the equation above;

3 moles of O₂ ---------> 2(18 g) of water

3.5 moles of O₂ ----------> x

\(x = 3.2 \times [\frac{2 \ moles \ H_2O}{3 \ moles \ O_2} ] \times[ \frac{18.02 \ g \ H_2O}{1 \ mole \ H_2O} ]\)

Thus, option C is the correct set of the problem for mass of water produced by 3.2 moles of oxygen and an excess ethene.

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The total concentration of ions remaining in the solution is 0.0007 M.

To solve this problem, we need to determine the concentration of both magnesium nitrate and sodium hydroxide before the solutions are mixed, and then use the reaction between magnesium nitrate and sodium hydroxide to determine the concentration of ions remaining in solution after the reaction is complete.

To calculate the total concentration of ions remaining in solution after the reaction is complete, we need to first determine the number of moles of each reactant present before the reaction occurs. To do this, we can use the molar mass of each compound to convert the mass of each compound to moles.

First, we can calculate the number of moles of magnesium nitrate present in the 22.02 mL solution:

Number of moles of magnesium nitrate = (1.615 g magnesium nitrate) / (148.32 g/mol magnesium nitrate) = 0.0109 moles magnesium nitrate

Next, we can calculate the number of moles of sodium hydroxide present in the 28.64 mL solution:

Number of moles of sodium hydroxide = (1.073 g sodium hydroxide) / (40.00 g/mol sodium hydroxide) = 0.0268 moles sodium hydroxide

Now that we know the number of moles of each reactant, we can use the balanced chemical equation for the reaction between magnesium nitrate and sodium hydroxide to determine the number of moles of each product that will be formed:

Magnesium nitrate + Sodium hydroxide -> Magnesium hydroxide + Sodium nitrate

1 mole magnesium nitrate + 1 mole sodium hydroxide -> 1 mole magnesium hydroxide + 1 mole sodium nitrate

Since we have 0.0109 moles of magnesium nitrate and 0.0268 moles of sodium hydroxide, the number of moles of each product that will be formed is also 0.0109 moles for magnesium hydroxide and 0.0268 moles for sodium nitrate.

Finally, we can use the number of moles of each product and the total volume of the solution to calculate the concentration of each product in the solution. The total volume of the solution is 22.02 mL + 28.64 mL = 50.66 mL.

The concentration of magnesium hydroxide in the solution is:

(0.0109 moles magnesium hydroxide) / (50.66 mL solution) = 0.0002 M magnesium hydroxide

The concentration of sodium nitrate in the solution is:

(0.0268 moles sodium nitrate) / (50.66 mL solution) = 0.0005 M sodium nitrate

The total concentration of ions remaining in the solution after the reaction is complete is the sum of the concentration of the magnesium ions and the concentration of the sodium ions. The concentration of the magnesium ions is 0.0002 M, and the concentration of the sodium ions is 0.0005 M, so the total concentration of ions remaining in the solution is 0.0002 M + 0.0005 M = 0.0007 M.

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Answer:

Acidic.

Explanation:

Hello,

In this case, we can know whether the solution is basic, acidic or neutral by computing the pH given the concentration of hydronium as shown below:

\(pH=-log([H^+])=-log(3.2x10^{-4})\\\\pH=3.49\)

Therefore, since the pH is lower than 7, we sum up the solution is acidic.

Best regards.

Answer: B. Volcanic eruption

Explanation:

A volcano is firmed when molten rocks is formed to the surface of the Earth. Volcanoes release molten rocks, ash, and gases to the Earth's surface.

Volcanoes are agents of change as the eruptions lead to the formation of new landforms and also destroy several things that they come in contact with.

Volcanic eruptions also occurs due to plate tectonics. Other events that happen due to plate tectonics also include earthquakes, and tsunamis.

Answer:B

Explanation:

Answer:

The nucleus represents a major evolutionary transition. As a consequence of separating translation from transcription many new functions arose, which likely contributed to the remarkable success of eukaryotic cells. Here we will consider what has recently emerged on the evolutionary histories of several key aspects of nuclear biology; the nuclear pore complex, the lamina, centrosomes and evidence for prokaryotic origins of relevant players.

Answer:

Refer to the picture. I managed to solve a few.

Answer:

we need 19.52 g of sugar to produce 10 g of ethanol.

Explanation:

The balanced chemical equation for the fermentation of glucose (sugar) to ethanol (C2H5OH) is:

C6H12O6 → 2C2H5OH + 2CO2

From the equation, we can see that one mole of glucose (C6H12O6) reacts to produce two moles of ethanol (C2H5OH). To determine how many grams of sugar are needed to produce 10g of ethanol, we need to use stoichiometry and the molar mass of glucose.

The molar mass of glucose is 180.16 g/mol, and the molar mass of ethanol is 46.07 g/mol. Therefore, we can calculate the number of moles of ethanol produced from 10 g as follows:

moles of C2H5OH = mass / molar mass = 10 g / 46.07 g/mol = 0.217 moles

Since two moles of ethanol are produced from one mole of glucose, we can calculate the number of moles of glucose needed as follows:

moles of glucose = 0.217 moles / 2 = 0.1085 moles

Finally, we can calculate the mass of glucose needed as follows:

mass of glucose = moles of glucose × molar mass of glucose

mass of glucose = 0.1085 moles × 180.16 g/mol

mass of glucose = 19.52 g

\( \:\:\:\:\:\: \sf \underline{\pink{C_6H_{12}O_6} \longrightarrow \pink{2\:C_2H_5OH}+2CO_2}\\\)

As per this equation, 1 mole of \(\sf C_6H_{12}O_6 \) produces 2 moles of \(\sf C_2H_5OH\) and 2 moles of \(\sf CO_2\)

Molar mass of 1 mole of \(\sf C_6H_12O_6 \)-

\( \:\:\:\:\:\:\longrightarrow \sf Molar\: Mass_{( C_6H_{12}O_6 )} = 12\times 6 + 1\times 12 + 16 \times 6\\\)

\( \:\:\:\:\:\:\longrightarrow \sf Molar\: Mass_{( C_6H_{12}O_6 )} =\underline{180 \:grams }\\\)

Molar Mass of 2 moles of \(\sf C_2H_5OH\)-

\( \:\:\:\:\:\:\longrightarrow \sf Molar \:Mass _{( C_2H_5OH)} = 2\bigg(12 \times2 + 1\times 5 + 16 +1\bigg)\\\)

\( \:\:\:\:\:\:\longrightarrow \sf Molar \:Mass _{( C_2H_5OH)} =2\times 46 \\\)

\( \:\:\:\:\:\:\longrightarrow \sf Molar \:Mass _{( C_2H_5OH)} =\underline{92\: grams }\\\)

As per equation, 92 grams of \(\sf C_2H_5OH\) can be produced from 180 grams of sugar. So, for making 10 grams of \(\sf C_2H_5OH\),we have to multiply 180 by 10 and then divide by 92. 180 grams of sugar is needed to make 92 grams of ethanol. Therefore -

\( \:\:\:\:\:\:\longrightarrow \sf \dfrac{180\times 10}{92}\\\)

\( \:\:\:\:\:\:\longrightarrow \sf \underline{\pink{19.565 \:grams }}\\\)

19.565 grams of sugar will be needed to make 10 g \(\sf C_2H_5OH\)

According to the VSEPR theory, a molecule or ion of CO2 will have a flat linear shape. Option A

In CO2, the carbon atom forms double bonds with each oxygen atom. The carbon-oxygen double bonds consist of two pairs of electrons, which are arranged linearly, leading to a linear molecular shape.

The VSEPR theory suggests that electron pairs in the valence shell of the central atom repel each other and try to position themselves as far apart as possible, resulting in the linear shape.

The VSEPR theory allows us to predict the molecular geometry based on the arrangement of bonding and non-bonding electron pairs around the central atom. In the case of CO2, there are no lone pairs of electrons on the carbon atom, and the molecule has a symmetrical arrangement, leading to a linear shape. Option A

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The concept VSEPR theory is mainly based on the arrangement of electron groups. This theory is generally used to predict the geometry of the molecules.

The Valence shell electron pair repulsion theory is based on the assumption that valence shell electron pairs repel each other and are oriented in space as far apart as possible to minimize mutual repulsion.

Each group around the central atom is designated as a bonding pair or non-bonding pair. For example BeF₂ is a two electron group in which the number of bond pairs on the central 'Be' atom is two.

Similarly the molecule BCl₃ is a three electron group, the number of electron pairs on the 'Be' atom is 3.

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Answer:

1.811 g

Explanation:

The computation of the mass need to use to make the solution is shown below:

We know that molarity is

\(Molarity = \frac{Number\ of\ moles}{Volume\ in\ L}\)

So,

\(Number\ of\ moles = Molarity\ \times Volume\ in\ L\)

\(= 0.223\times 0.141\)

= 0.031 moles

Now

\(Mass = moles \times Molecualr\ weight\)

where,

The Molecular weight of NaCl is 58.44 g/mole

And, the moles are  0.031 moles

So, the mass of NaCL is

\(= 0.031 \times 58.44\)

= 1.811 g

We simply applied the above formulas

Answer:

log = ( - 0.51 z 2) / ( 1 + ( / 305)

Explanation:

Answer: The answer is B. I took the test on edg and got it right :)

Answer:

B

The liquid contains only one element.

Explanation:

I got it correct

we would need 2625.13 grams (or 2.62513 kilograms) of NaCl.

To calculate the mass of NaCl required to produce a 26.4 mol/L solution with a 1.7 L volume, we need to use the formula that relates the mass of solute, moles of solute, and molarity:Molarity (M) = moles of solute / liters of solution Rearranging this formula, we get:moles of solute = Molarity (M) x liters of solutionWe can use this formula to find the moles of NaCl needed:moles of NaCl = 26.4 mol/L x 1.7 L = 44.88 molNow, we can use the molar mass of NaCl to convert from moles to grams. The molar mass of NaCl is 58.44 g/mol:mass of NaCl = moles of NaCl x molar mass of NaClmass of NaCl = 44.88 mol x 58.44 g/mol = 2625.13 gTo produce a 26.4 mol/L solution with a 1.7 L volume.

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