Why is it necessary to find the percent yield of a reaction? A. to determine the efficiency of the reaction B. to determine the amount of reactants in the reaction C. to determine the amount of products in the reaction D. to determine the limiting reactant of the reaction

Answer:

[tex]\boxed{\text{417 kJ}}[/tex]

Explanation:

There are three heat transfers in this process:

Total heat = warming the ice + melting the ice + warming the water  

       q        =           q₁               +           q₂             +              q₃

       q        =       mC₁ΔT₁          +        mΔHfus       +          mC₂ΔT₂

Let's calculate these heat transfers separately.

Data:

      m = 1 kg = 1000 g

     C₁ = 2.108 J·°C⁻¹g⁻¹

     C₂ = 4.184 J·°C⁻¹g⁻¹

ΔHfus = 333 J/g

Tmax =   15 °C

 m.p. =    0 °C

Tmin = -10 °C

Calculations:

ΔT₁ = 0 – (-10) = 10 °C

q₁ = 1000 × 2.108 × 10 = 21 080J = 21.08 kJ

q₂ = 1000 × 333 = 333 000 J =333 kJ

ΔT₂ = 15 - 0 = 15 °C

 q₃ = 1000 × 4.184 × 15 = 62 760 J = 62.76 kJ

q = 21.08 + 333 + 62.76 = 417 kJ

You must add [tex]\boxed{\textbf{417 kJ}}[/tex].

Answer:

9.0 g/cm³

Explanation:

Density can be computed with the formula:

[tex]D=\dfrac{M}{V}[/tex]

Where:

D = Density

M = Mass

V = Volume

In your problem we are given:

84 cm³ = volume

760 g = mass

So we just plug in our given into the formula:

[tex]D=\dfrac{M}{V}[/tex]

[tex]D=\dfrac{760g}{84cm^{3}}[/tex]

[tex]D=9.05g/cm^{3}[/tex]

The answer would then be:

9.0 g/cm³

Answer:

it is 9.04 or 9.0

Explanation:

Answer:

The correct answer is B

Explanation:

Nuclear Fusion is a raection in which two or more atomic nuclei are combined together to form a heavier nuclei.

The study of chemicals and bonds is called chemistry. The element is made of electrons, protons, and neutrons.

The correct answer is option B that is involves the collision of two nuclei.

The atomic nucleus is the small, dense region consisting of protons and neutrons at the center of an atom.

Fusion means the joining of two-component and according to the question, the correct answer is option B.

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Answer:

Graphics can sometimes convey more information in a brief amount of space than an author can explain in a paragraph.

Answer is A Access pictures of the area taken by satelites.

Explanation: Satelites are the only thing out of these four answers that does not requir power supply from the town. Hope it helped!

The newspaper can get the pictures of the place by accessing pictures of the area taken by satellites.

Satellites use magnetic sensors to collect electromagnetic radiation of specific wavelength reflected from the Earth surface.

These sensors are able to detect wavelengths that are not possible by human eyes.

The power supply that has been cut off does not affect the satellite, hence it will detect the waves reflected from the Earth surface during the hurricane and the photo of the place can used by the newspaper for its morning edition.

Thus, the best way for the newspaper to get the pictures of the place is to access pictures of the area taken by satellites.

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Charles’ Law........

Answer: Charles' Law

Explanation:

Charles' Law: This law states that volume is directly proportional to the temperature of the gas at constant pressure and number of moles.

[tex]V\propto T[/tex]     (At constant pressure and number of moles)

[tex]{V_1\times T_1}={V_2\times T_2}[/tex]

where,

[tex]V_1[/tex] = initial volume of gas

[tex]V_2[/tex] = final volume of gas

[tex]T_1[/tex] = initial temperature of gas

[tex]T_2[/tex] = final temperature of gas

Therefore, the volume and absolute temperature of a fixed quantity of gas are directly proportional under constant pressure conditions.

Answer:

He is determining physical properties that are sufficient to identify the metal.

Explanation:

So, the right choice is:

He is determining physical properties that are sufficient to identify the metal.

A! He is determining physical that are sufficient to identify the metal.

Answer:

34.44 g.

Explanation:

Fe + S → FeS,

It is clear that 1.0 mol of Fe reacts with 1.0 mol of S to produce 1.0 mol FeS.

no. of moles of Fe = mass/atomic mass = (60.0 g)/(55.845 g/mol) = 1.074 mol.

no. of moles of FeS = mass/molar mass = (90.0 g)/(87.91 g/mol) = 1.024 mol.

∵ Fe reacts with S with (1: 1) molar ratio.

∴ The no. of moles of S needed to react with Fe is 1.074 mol.

∴ The no. of grams of S needed = no. of moles x molar mass = (1.074 mol)(32.065 g/mol) = 34.44 g.

Answer:

The answer is:

A. 30 grams

Explanation:

Answer:

The theoretical yield of copper is approximately 1.65 grams.

Explanation:

Relative atomic mass data from a modern periodic table:

As a metal, aluminum is more reactive than copper. Aluminum will reduce the [tex]\text{Cu}^{2+}[/tex] ion in [tex]\text{CuCl}_2\;(aq)[/tex] to [tex]\text{Cu}\;(s)[/tex]. This process will form a positive aluminum ion, which will then combine with chloride ions in the solution. What will be the charge on each aluminum ion? Aluminum is in IUPAC Group 13 of the periodic table. Each aluminum atom contains three valence electrons. As a main group metal in the p-block, each atom will lose all three of its valence electrons to form [tex]\text{Al}^{3+}[/tex] ions with three positive charges. Each ion will combine with three [tex]\text{Cl}^{-}[/tex] ions to produce a species with the empirical formula [tex]\text{Al}\text{Cl}_3[/tex].

Reactants:

Products:

Let the coefficient in front of [tex]\text{AlCl}_3\;(aq)[/tex] be [tex]1[/tex].

[tex]\begin{array}{cccccccl}\text{Al}\;(s) & +& \text{CuCl}_2\;(aq) & \to & \text{AlCl}_3\;(aq) & + & \text{Cu}\;(s)\\ & & & & {\bf 1} & & &\begin{aligned}&\text{Assign "1" to the most}\\[-0.5em]&\text{complex compound.}\end{aligned} \\ {\bf 1}& &{\bf 3/2} & & 1 & & &\begin{aligned}&\text{Al and Cl atoms}\\[-0.5em]&\text{conserve.}\end{aligned}\end{array}[/tex][tex]\begin{array}{cccccccl}\phantom{\;\text{Al}\;(s)} & \phantom{+}& \phantom{\text{CuCl}_2\;(aq)} & \phantom{\to} & \phantom{\text{AlCl}_3\;(aq)} & \phantom{+} & \phantom{\text{Cu}\;(s)}\\[-1em]1& &{3/2} & & 1 & & {\bf 3/2} &\begin{aligned}&\text{Cu atoms shall also}\\[-0.5em]&\text{conserve.}\end{aligned} \\2& &{3} & & 2 & & {3} &\begin{aligned}&\text{Multiply all}\\[-0.5em]&\text{coefficients by two}\\[-0.5em]&\text{to eliminate fractions.}\end{aligned}\end{array}[/tex].

Hence the balanced equation:

[tex]2 \;\text{Al} \;(s) + 3 \;\text{CuCl}_2\;(aq) \to 2\;\text{AlCl}_3\;(aq) + 3\;\text{Cu}\;(s)[/tex].

Assume that [tex]\text{CuCl}_2[/tex] is the limiting reactant.

Formula mass of [tex]\text{CuCl}_2[/tex]:

[tex]M(\text{CuCl}_2) = 63.546 + 2 \times 35.45 = 134.446\;\text{g}\cdot\text{mol}^{-1}[/tex].

Number of moles of [tex]\text{CuCl}_2[/tex] available:

[tex]\displaystyle n = \frac{m}{M} = \frac{3.5}{134.446} = 0.0260328\;\text{mol}[/tex].

The ratio between the coefficient in front of [tex]\text{CuCl}_2[/tex] is the same as the coefficient in front of [tex]\text{Cu}[/tex].

[tex]\displaystyle \frac{n(\text{Cu})}{n(\text{CuCl}_2)} = \frac{\text{Coefficient in front of } n(\text{Cu})}{\text{Coefficient in front of } n(\text{CuCl}_2)} = \frac{3}{3} = 1[/tex].

[tex]n(\text{Cu}) = 1 \cdot n(\text{CuCl}_2) = 0.0260328\;\text{mol}[/tex].

Mass of copper that is expected to be produced if [tex]\text{CuCl}_2[/tex] is the limiting reactant:

[tex]m(\text{Cu}) = n(\text{Cu}) \cdot M(\text{Cu}) = 0.0260328 \times 63.546 =1.65\;\text{g}[/tex].

Assume that [tex]\text{Al}[/tex] is the limiting reactant.

The methods are similar. Try the steps above yourself.

Formula mass of [tex]\text{Al}[/tex]:

[tex]M(\text{CuCl}_2) = 26.982\;\text{g}\cdot\text{mol}^{-1}[/tex].

Number of moles of [tex]\text{Al}[/tex] available:

[tex]\displaystyle n = \frac{m}{M} = \frac{0.5}{26.982} = 0.0185\;\text{mol}[/tex].

The ratio between the coefficient in front of [tex]\text{CuCl}_2[/tex] is [tex]3/2[/tex] times the coefficient in front of [tex]\text{Al}[/tex].

[tex]\displaystyle \frac{n(\text{Cu})}{n(\text{Al})} = \frac{\text{Coefficient in front of } n(\text{Cu})}{\text{Coefficient in front of } n(\text{Al})} = \frac{3}{2}[/tex].

[tex]\displaystyle n(\text{Cu}) = \frac{3}{2} \cdot n(\text{Al}) = 0.0277963\;\text{mol}[/tex].

Mass of copper that is expected to be produced if [tex]\text{Al}[/tex] is the limiting reactant:

[tex]m(\text{Cu}) = n(\text{Cu}) \cdot M(\text{Cu}) = 0.0277963 \times 63.546 =1.77\;\text{g}[/tex].

[tex]1.65\;\text{g} < 1.77\;\text{g}[/tex]. The first assumption is valid. [tex]\text{CuCl}_2[/tex] will run out before all [tex]0.5\;\text{g}[/tex] of aluminum are consumed, Only [tex]1.65\;\text{g}[/tex] of copper will be produced.

Answer:

C. Excess nutrients promote the growth of algae

Explanation:

The eutrophication can simply be explained as an over-saturation of the waters with nutrients. This usually happens because of the human activity, with the largest sources that contribute to this being the fecal matter from the farmed animals and the fertilizers used in the agriculture. They are either released into the water directly or manage to reach it on their own by natural means. Once they reach the water they increase the amount of nutrients a lot, and that prompts the growth of the algae. As the algae grow more and more and occupy more and more area, they block the sunlight, so the organisms that use photosynthesis die out. Also, the algae contribute to eliminating the oxygen of the waters, so the fish and the other organisms die out as well, leading to a total collapse of the ecosystem.

Answer:

When substances combine to form new substances, the properties of the reactants are preserved.

Explanation:

When the two elements Na and Cl combine, they produce a stable, crystalline solid known commonly as table salt.  This explains as when substances combine to form new substances, the properties of the reactants are preserved. Therefore, option A is correct.

Elements are pure substances that cannot be broken down into simpler substances by chemical means. They are made up of atoms, which have a specific number of protons in their nucleus that defines their atomic number.

In a chemical reaction, the atoms that form the first substances are regrouped into other molecules, and these new substances have various properties from those of the reactants. The total number of all types of atoms is kept, and thus the mass does not change.

Thus, option A is correct.

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Answer:

[tex]\boxed{\text{311 K}}[/tex]

Explanation:

We can use the Ideal Gas Law and solve for T.

pV = nRT

Data:  

p = 0.998 atm

V = 1.20 L

n = 0.0470 mol

R = 0.082 06 L·atm·K⁻¹mol⁻¹

Calculation:

0.998 × 1.20 = 0.0470 × 0.082 06 × T

1.198 = 0.003 857T

[tex]T = \dfrac{1.198}{0.003 857} = \textbf{311 K}[/tex]

The Kelvin temperature is [tex]\boxed{\textbf{311 K}}[/tex], not 307 K.

I suppose you could choose the last square, as it has the closest value.

Air, soil, plants, fuels and water are examples of natural resources. Some of these (ex. air & water) are renewable. Some however are nonrenewable (ex. fuels). If not conserved and protected, we may lose some of these resources to pollution or depletion.

The Earth's natural resources include air, water, soil, minerals, fuels, plants, and animals. Conservation is the practice of caring for these resourcesso all living things can benefit from them now and in the future. ... These are renewable resources. Otherresources, such as fossil fuels, cannot be replaced at all.

Source: National Geography

The average rate of the reaction over the first 580 seconds is approximately [tex]2.07 \times 10^{(-3)} M/s[/tex]. Thus, option C is correct.

To find the average rate of the reaction over the first 580 seconds, we can use the formula:

[tex]\[ \text{Average rate} = \frac{\text{Change in concentration}}{\text{Change in time}} \][/tex]

Given the concentrations at 0 s and 580 s, and the corresponding times, we can calculate the change in concentration and change in time:

Change in concentration = 1.8 M - 0.6 M = 1.2 M

Change in time = 580 s - 0 s = 580 s

Now, we can calculate the average rate:

Average rate = [tex]\(\frac{1.2 \text{ M}}{580 \text{ s}}\)[/tex]

Average rate = [tex]\(2.07 \times 10^{-3}\) M/s[/tex]

Therefore, the average rate of the reaction over the first 580 seconds is approximately [tex]2.07 \times 10^{(-3)} M/s[/tex]. Since this is closest to option C [tex](2.0 \times 10^{(-3)})[/tex], the answer is C.

72.71 . simple google search, you shouldnt waste points

For this case we have the [tex]CO_ {2}[/tex]

It is composed of one atom of carbon and two of oxygen.

The atomic mass of carbon and oxygen, which can be found in a periodic table, are given by:

[tex]C: 12 \frac {g} {mol}\\O: 16 \frac {g} {mol}[/tex]

Then, we find the atomic mass of [tex]CO_{2}[/tex]:

[tex]1 * 12 \frac {g} {mol} = 12 \frac {g} {mol}\\2 * 16 \frac {g} {mol} = 32 \frac {g} {mol}[/tex]

Adding we have:

[tex]44 \frac {g} {mol}[/tex]

To find the percentage of oxygen, we divide the atomic mass of the two oxygen atoms between that of [tex]CO_{2}:[/tex]

[tex]\frac {32} {44} * 100 = 72.73[/tex]%

Thus, the percentage of oxygen is 72.73%

Answer:

72.73%

Answer: About 160 grams

Explanation: The formula for this reaction is 4Fe + 3O2 = 2Fe2O3. Since only 2 moles of iron are reacting then only 1 mole of the product will be produced. The molar mass of the product is about 160 grams.

Answer:

471 g

Explanation:

When 8.73 moles of benzene react with excess oxygen, approximately 471.42 grams of water will be produced.

In order to find out how many grams of water are produced from the reaction of 8.73 moles of benzene (C6H6) with excess oxygen (O2), we need to know the balanced chemical reaction. The combustion reaction for benzene looks like this:

C6H6 + 7.5O2 -> 6CO2 + 3H2O

From the balanced combustion reaction, it can be seen that for each mole of benzene reacting, 3 moles of water are produced. So, if 8.73 moles of benzene react, it would yield 3 times this many moles of water: 8.73*3 = 26.19 moles of water.

As the molar mass of water (H2O) is approximately 18 g/mole, we can calculate grams of water by multiplying moles of water and molar mass of water.

26.19 moles * 18 g/mole = 471.42 grams of water

So, approx 471.42 grams of water can be produced when 8.73 moles of benzene react with excess oxygen.

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lowest melting point-covalent solids

highest melting point-ionic solids

Molecular solids like ice tend to have lower melting points due to weaker intermolecular forces, while ionic solids such as sodium chloride have high melting points due to strong ionic bonds. Network covalent solids also have high melting points, whereas amorphous solids soften over a range of temperatures.

The melting point of a solid is the temperature at which the solid changes into a liquid. It reflects how much kinetic energy is required for the particles within a solid to overcome the attractive forces keeping them in place. In general, molecular solids, such as ice (melting point of 0°C), tend to have lower melting points due to weaker intermolecular forces like hydrogen bonds or London dispersion forces. On the other hand, ionic solids, such as sodium chloride (melting point of 801°C), display the highest melting points because the ionic bonds between their ions are very strong.

Network covalent solids often have high melting points as well since the atoms within the network are bonded by covalent bonds that require significant energy to break. By contrast, amorphous solids like butter do not have a sharp melting point but rather soften over a range of temperatures due to the lack of a well-ordered molecular structure like that seen in crystalline solids.

Answer:

The last choice is oxidation.

Explanation:

The this is a reaction in which the oxidation number of chromium metal

( 0 ) goes the an oxidation number of 3 in Cr3+.

Answer : The correct option is, [tex]Cr(s)\rightarrow Cr^{3+}(aq)+3e^-[/tex]

Explanation :

Redox reaction : It is a reaction in which the oxidation and reduction reaction takes place simultaneously.

Oxidation reaction : It is a reaction in which a substance looses its electrons. In this, oxidation state of an element increases. Or we can say that in oxidation, the loss of electrons takes place.

Reduction reaction : It is a reaction in which a substance gains electrons. In this, oxidation state of an element decreases. Or we can say that in reduction, the gain of electrons takes place.

The correct oxidation-half reaction will be :

[tex]Cr(s)\rightarrow Cr^{3+}(aq)+3e^-[/tex]

In this half oxidation reaction, the oxidation state of 'Cr' changes from (0) to (+3) that means the oxidation state increases that means it shows oxidation.

Answer:

Hydrogen sulfide is nonpolar. Even though the molecular geometry would allow for it to polar, the bonds are not polar, so the molecule isn't either. Polarity is determined by electronegativity.

[tex]H_2S[/tex] is a polar substance.

Polar particles form when two molecules don't share electrons similarly in a covalent bond. This happens when there is a distinction between the electronegativity of every molecule. An extraordinary distinction shapes an ionic bond, while a lesser contrast frames a polar covalent bond.  

If the electronegativity between the two ions is somewhere in the range of 0.5 and 2.0, the structure of the particle forms a polar covalent bond. In the event that the electronegativity distinction between the ions is more than 2.0, the bond is ionic. Ionic mixes are amazingly polar particles.  

Instances of polar particles include:  

Answer:hi guys it is both objects are the same temperature

Explanation:

Heat transfers from a warmer object to a colder one (such as an ice cube) until both objects are at the same temperature. This is a process known as conduction.

When an ice cube is placed on an object that is warmer than it, heat will be transferred from the warmer substance to the ice cube. This process will continue until both objects are the same temperature. This is explained by the physics law of heat transfer, specifically conduction, which is the process where heat energy is transferred between substances in direct contact with each other.

The warmer object will lose heat to the colder object (the ice cube) until equilibrium is reached and both objects have the same temperature. It may also coincide with other options like the ice melting or ice reaching 0°C, but this depends on the initial temperature of the warmer object.

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you can find the run by subtracting the X coordinate of the left point from that of the right point

You can find by subtracting the variable

Answer:

CaF₂+H₂SO₄ → CaSO₄+2HF     ΔH = +157.7KJ

Explanation:

Energy changes in chemical reactions is one of the most important issues in thermodynamics  especially the enthalpy of reaction (ΔHrxn)

           CaF₂+H₂SO₄+157.7KJ → CaSO₄+2HF

which can be expressed in alternate form as following

CaF₂+H₂SO₄ → CaSO₄+2HF     ΔH = +157.7KJ

Answer:

1. the outer layer of the eye: G scelra

2. when a light ray bends, or changes direction, when it moves from one material into another: F refraction

3. an optical instrument that makes objects that are far away look closer: K telescope

4. the point where all of the beams of light leaving a lens converge: focal point

5. a term for a medium that transmits nearly all the light rays that hit it: C transparent

6. the distance between any two peaks or any two troughs of a wave: J wavelength

7. a term used to describe a person who cannot see close objects clearly: B

farsighted

8. a term used to describe a person who cannot see faraway objects clearly: M nearsighted

9. a narrow beam of light that travels in a straight line: H light ray

10. a curved, transparent object used to refract light: lens

11. a word used to describe a medium that only allows some of the light rays that hit it to pass through it: E translucent

12. the process of converting light energy into...(can't see the rest)

13. (isn't visible either)

A I believe is correct

Answer:

metal spoon because travels fastest through solid objects

Explanation:

Answer:

Cellular Respiration

Explanation:

Cellular respiration is the process that occurs in both plant and animal cells, allowing them to convert glucose into ATP, the usable form of energy for cellular functions. While photosynthesis only happens in plants, cellular respiration is essential for both plants and animals, illustrating a fundamental connection between these two types of organisms.

The process that takes place in both plant and animal cells is cellular respiration. This is a series of metabolic pathways that extracts energy from the bonds in glucose, a sugar that's produced during photosynthesis in plants, and converts it into ATP (adenosine triphosphate), which is a form of energy that all living things can use.

Although plants are capable of photosynthesis, the process by which they convert solar energy into chemical energy (glucose), they also perform cellular respiration to break down this glucose into usable energy for cellular activities. Animals, which cannot perform photosynthesis, rely entirely on cellular respiration to convert energy from consumed food into ATP.

It's important to note that photosynthesis only occurs in photosynthetic organisms such as plants, algae, and certain bacteria, while cellular respiration occurs in virtually all living organisms. This highlights the interconnectedness of life processes, as the oxygen created as a byproduct of photosynthesis is used by animals during cellular respiration, and the carbon dioxide produced by animals during cellular respiration is utilized by plants during photosynthesis.

Answer:

Cr

Mn⁺¹

Fe⁺²

Explanation:

Answer:

3.8 liters

Explanation:

According to Avogadro’s Law  of gases

at constant temperature and pressure, the volume of all gases constitutes an equal number of molecules. In other words, the volume of any gas is directly proportional to the number of molecules of that gas.

∴ V ∝ n   or (V₁/V₂) = (n₁/n₂)

V₁= 2.5 L

n₁= 0.3 mol

n₂= 0.3 mol + 0.15 mol = 0.45 mol

using cross multiplication

(2.5 L / V₂) = (0.3 mol / 0.45 mol)

V₂= 3.8 L

∴ The right choice is 3.8 liters

Answer:

3.8 liters

Explanation:

Solution:

Density of iron( d)=?

Specific gravity of iron=7.87

Density of water at 4°C=1g/cm^3

we have,

specific gravity =density of object/density of water at 4°C

or,7.87=d/1

or, d=7.87g/cm^3

Again,

density=mass/ volume

or,7.87=7/V

or,V=7/7.87

or,V=0.88cm^3

therefore, volume occupied by iron is 0.88cm^3

Volume is a measurement if the amount of space an object occupies.