Use the following pairs of standard reduction potentials below to answer question 21. Respectively is A. Is the Half-reaction, and B. Is E^0(volts) ; A. Cr^ 2+ +2e^- ->Cr B.-0.913 A. Fe^2+ +2e^->Fe B. -0.447 A. Cd^2+ +2e^-> Cd B.-0.4030 A.Br2+2e^-> 2Br B. +1.06
Question 21. For each of these pairs of half -reactions , write a balanced equation for the overall cell reaction and calculate the standard cell potential, E^0cell A. Half-reactions: Cd^ 2+ (aq)+2e^ -> Cd(s); Cr^ 2+ (aq)+2e^-> Cr(s) Cell reaction : E^0cell: B. Half-reactions: Fe^ 2+ (aq)+2e^ -> Fe(s); Br2 (g)+2e^- ->2Br^ - (aq) Cell reaction : E^0cell

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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Starch is made of units of and it is broken down by an enzyme called amylase.(c)

Starch is a polysaccharide made up of glucose units, which are broken down into simpler glucose molecules by the enzyme amylase. Amylase is secreted by the salivary glands and pancreas, and it breaks down starch into smaller molecules that can be absorbed by the body.

This process of breaking down starch into glucose is crucial for energy production in the body, and it is also important for regulating blood sugar levels. In summary, starch is broken down by amylase into glucose, which is then used by the body for energy.

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The masses and volumes indicated, calculate the density in grams per cubic centimeter mass = 1.00 lb; volume = 500. cm^3. Thus option c is correct.

Density is defined as a material is the measure of how densely it is packed together.

It can also be defined as a measure of the density of a substance or object's mass.

The SI unit of density is kilogram per cubic meter or gram per cubic meter

Density can be expressed as

Density = mass / volume

Density = 1.00 / 500

Density = 0.002 lb / cm^3

Thus, the masses and volumes indicated, calculate the density in grams per cubic centimeter mass = 1.00 lb; volume = 500. cm^3. Thus option c is correct.

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Answer:

The answer is True

Explanation:

I got it right on my quiz, hope this helps!

To draw the two circles, we would need to draw a smaller circle with a diameter of 2,532.5 miles (representing the moon) and a larger circle with a diameter of 75,974.4 miles (representing the Earth) that is 30 times larger than the smaller circle.

If we assume that the larger circle represents the Earth, then the diameter of the Earth would be 30 times the diameter of the smaller circle representing the moon. Let's say that the diameter of the smaller circle is x. Then the diameter of the larger circle (Earth) would be 30 times x or 30x.

To find the correct distance from Earth to the moon at this scale, we need to know the actual distance from Earth to the moon, which is approximately 238,855 miles or 384,400 kilometers. If we divide this distance by the scale factor of 30, we get:

238,855 miles / 30 = 7,961.8 miles

Therefore, the diameter of the smaller circle (moon) would be approximately 7,961.8 miles / π = 2,532.5 miles (rounded to one decimal place). And the diameter of the larger circle (Earth) would be 30 times that or 75,974.4 miles

So, to draw the two circles, we would need to draw a smaller circle with a diameter of 2,532.5 miles (representing the moon) and a larger circle with a diameter of 75,974.4 miles (representing the Earth) that is 30 times larger than the smaller circle.

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Answer:

No.2)answer

Explanation:

As elevation increases, atmospheric pressure decreases, causing water to boil at lower temperatures, which lengthens cooking times.A pressure cooker provides constant, precise atmospheric conditions inside the cooker, reducing cooking times even at high altitudes.

No.3 Answer

When something changes its state of matter (formally, a phase change), regardless of whatever it is, it remains at it's melting point/boiling point/freezing point UNTIL all of it has changed its state of matter.

When something changes its state of matter (formally, a phase change), regardless of whatever it is, it remains at it's melting point/boiling point/freezing point UNTIL all of it has changed its state of matter.So, to clear up, ice and water can both exist at 0°C at 1 atmosphere. The difference is that water has more energy than ice does, therefore solid water can break up the bonds and become a liquid.

When something changes its state of matter (formally, a phase change), regardless of whatever it is, it remains at it's melting point/boiling point/freezing point UNTIL all of it has changed its state of matter.So, to clear up, ice and water can both exist at 0°C at 1 atmosphere. The difference is that water has more energy than ice does, therefore solid water can break up the bonds and become a liquid.I heavily suggest you take a look at calorimetry, it explains it greatly and is related to your question.

Answer:

16:1

Explanation:

Atoms of element X weigh 32 times more than atoms of element Y. We can write this in a symbolic way.

mX = 32 mY   [1]

where,

A compound has the formula: XY₂, that is, in 1 molecule of XY₂ there is 1 atom of X and 2 atoms of Y. The ratio of the mass of X to the mass of Y in this compound equals:

mX/2 mY  [2]

If we substitute [1] in [2], we get:

mX/2 mY = 32 mY/2 mY = 16 = 16:1

283.875 mL of ethanol are in a 0.750gallon sample of the gasohol. Therefore, the correct option is option A.

Ethanol, sometimes known as ethyl alcohol, is a chemical liquid having the formula C2H5OH. Its primary application is as a solvent. To comprehend the chemical composition of ethanol, you must first grasp what alkenes are.

Alkenes are carbon and hydrogen molecules containing at at least one double bond between two carbons. Ethene is an example of an alkene.

1 gall = 3.785 L

0.750gallon =?

0.750gallon ×3.785 L / 1 gallon

= 2838.75 ml

10% of  2838.75 ml= 283.875 mL

Therefore, the correct option is option A.

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To balance the equation and identify the type of reaction, let's start by assigning coefficients to each compound: 2H2O + 1SO3 -> 1H2SO4

To balance the equation, we need to ensure that the number of atoms on both sides is the same. Here, we have two hydrogen (H) atoms on the left side and two on the right side, so hydrogen is already balanced.

We have two oxygen (O) atoms on the left side and four on the right side, so we need to balance oxygen by adding a coefficient of 2 in front of the water molecule:

2H2O + 1SO3 -> 1H2SO4

Now the equation is balanced with two hydrogen, four oxygen, and one sulfur (S) atom on both sides.

The type of reaction represented by this equation is a combination or synthesis reaction. In a combination reaction, two or more substances combine to form a new compound. In this case, water (H2O) and sulfur trioxide (SO3) combine to form sulfuric acid (H2SO4).

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Answer:

D)Polishing..

Answer:

Wouldn't it be rusting

Explanation:

Melting and bending are physical changes so is polishing. so rusting is the only choice, for metal to rust wouldn't it need a chemical change.

Answer:

radiation, hope this helps

There are 15.4 equivalents of chloride ion present in the solution

We need to multiply the total number of moles of chloride ion in the solution by the number of equivalents.

The molar mass of NaCl is 58.44 g/mol, so 3.5 mol of NaCl contains :

3.5 mol NaCl x 2 mol Cl⁻/1 mol NaCl = 7 mol Cl⁻

Similarly, the molar mass of MgCl₂ is 95.21 g/mol, so 4.2 mol of MgCl₂ contains:

4.2 mol MgCl₂ x 2 mol Cl⁻/1 mol MgCl₂ = 8.4 mol Cl⁻

Therefore, the total number of moles of chloride ion in the solution is:

7 mol Cl⁻ + 8.4 mol Cl⁻ = 15.4 mol Cl⁻

By dividing the total number of moles by the number of equivalents per mole, we can finally determine how many equivalents of the chloride ion there are. There is one equivalent of the chloride ion per mole since it has a valency of -1.

15.4 mol Cl⁻ x 1 eq/mol = 15.4 eq

So there are 15.4 equivalents of chloride ion present in the solution.

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The gravimetric factor for Br- using silver bromide is 0.425.

The gravimetric factor is an expression that is used to convert grams of a compound into grams of a single element.

It is expressed as a ratio of the formula weight (FW) of the substance that is being determined to that of a second substance that is weighed.

For example formula of silver bromide is AgBr and the formula mass of silver bromide is 188 g/mol

Formula mass of bromide ion = 80 g/mol

Gravimetric factor = 80/1188

Gravimetric factor = 0.425

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Answer:

the boiling point of solution at 3 decimal point is 100.329०C Ans.

Explanation:

given data -

molality of Nacl = 0.321 m

molal boiling point elevation constant (Kb) =0.512०C/m

# formula of change of boiling point of sample =

∆ Tb =i × Kb × m

Kb = molal boiling point of elevation constant

m = molality

i = vont's hoff factor.

Nacl is strong electrolyte and its 100% dissociate so the value of i for Nacl is 2

put value in the formula

∆ Tb = 2 × 0.512 ०C/m × 0.321m

= 0.3287

= 0.329०C

∆Tb = T'b - Tb

T'b = boiling point of solution

Tb= boiling point of solvent( water)

0.329०C = T'b - 100०c ( boiling point of water = 100०C)

T'b = 0.329०C + 100०C

= 100.329०C

hope this helps

MgSO4 + Na3PO4 = Na2SO4 + Mg3(PO4)2

Answer: The products of Na3PO4 + MgSO4 are Na2SO4 + Mg3(PO4)2

Explanation:

The percent recovery would be 83.65%

The percent recovery of a recrystallization reaction can be mathematically deduced as:

Percent recovery = recovered amount/amount of original sample x 100%

In this case, the recovered amount = 2.61 g, and the original amount of sample = 3.12. Thus:

Percent recovery = 2.61/3.12 x 100%

                           = 83.65%

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Answer:

The element is strontium and the number of neutrons it have is 51.

Explanation:

Based on the given information, the ionic compound is,  

XCl₂ ⇔ X₂⁺ + 2Cl⁻

X2+ is the ion of the mentioned element

As mentioned in the given question, the number of electrons of the element X is 36 and as seen from the reaction the charge present on the ion is +2. Now the atomic number will be,  

No. of electrons = atomic number - charge

36 = atomic number - 2

Atomic number = 38

Based on the periodic table, the atomic number 38 is for strontium element, and the sign of strontium is Sr. Hence, the element X is Sr.  

Now based on the given information, the mass number of the element is 89. Now the no. of neutrons will be,  

No. of neutrons = mass number - atomic number

= 89 - 38

= 51 neutrons.  

The molality of the solution is 0.0256 m.

The mole fraction of glycerol is  0.00046

The percent by mass concentration of glycerol is 0.23%

The ppm concentration is 2300 ppm

Molality is a measure of the concentration of a solute in a solution. It is defined as the number of moles of solute per kilogram of solvent.

The formula for molality is:

molality = moles of solute / mass of solvent in kilograms

1) Density of water = mass/volume

Mass of water = Density * volume of water

Mass =\(0.9982 g/mL * 998.9 mL\)

Mass =0.997 Kg of water

Number of moles of the glycerol =  \(2.550* 10^-2 M * 1 L\)

= \(2.550*10^-2\) moles

Molality of the solution = \(2.550*10^-2\)  moles/0.997 Kg

= 0.0256 m

Number of moles of water = 998.9/18 g/mol

= 55.5 mole

Mole fraction of glycerol = \(2.550*10^-2\) /\(2.550*10^-2\)  + 55.5

= 0.00046

By percent by mass;

2.3/1001.2 * 100/1

= 0.23%

Mass of glycerol = 2.3 g

Volume of solution = 1 L

Thus we have concentration in ppm as;

\(2.3 * 10^3\) mg/ 1 L =2300 ppm

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Answer:

it would take 2 years

Explanation:

93/55=1.69--->1.70------>2

Answer:

Q = 81.59kJ

Explanation:

Hello,

The heat of condensation is the energy required to to convert the steam into water.

Mass = 195g

Specific heat capacity of water = 4.184J/g°C

Initial temperature(T1) = 100°C

Final temperature(T2) = 0°C

Heat energy (Q) = ?

Heat energy (Q) = mc∇T

M = mass of the substance

C = specific heat capacity of the substance

∇T = T2 - T1 = change in temperature of the substance

Q = 195 × 4.184 × (0 - 100)

Q = -81588J

Q = -81.588kJ

The heat required for the condensation of 195g of steam is 81.59kJ

The car took 3 seconds to accelerate from 15 m/s to 30 m/s with an acceleration of 5 m/s^2.

We can use the following kinematic equation to solve this problem:

v = u + at

Where

Given:

u = 15 m/s (initial velocity)

v = 30 m/s (final velocity)

a = 5 m/s^2 (acceleration)

Substituting the given values into the equation, we get:

30 m/s = 15 m/s + 5 m/s^2 × t

Simplifying and solving for t, we get:

5 m/s^2 × t = 15 m/s

t = 15 m/s ÷ 5 m/s^2 = 3 seconds

Therefore, the car took 3 seconds to accelerate from 15 m/s to 30 m/s with an acceleration of 5 m/s^2.

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Answer:

16 neutrons

Explanation:

now that protons are equal to electrons, there are 15 electrons. The mass is equal to 31.0, which is the ≡ of protons and ≡ neutrons added together. To find the number of neutrons, subtract the atomic # from the total mass #. 31-15=16 this would be equal to 16 now that the atomic has 31 and the mass is 15 subtract them ... you would get 16 neutrons inside the nucleus.

hope this helped ((((: if it did then please mark brainliest and have a wonderful day d:

Answer:

16

Explanation:

To find the neutrons, it's always mass-atomic number. Since the atomic number for an atom is always the protons, it's really mass-protons.

31-15=16

1. The constituent gases of air are:

2. The surrounding air is not seen with the eyes because it is transparent. Air molecules are not visible to the na-ked eye, and they do not scatter or absorb visible light significantly. Therefore, air appears colorless and transparent.

3. To prove that air supports burning, you can perform an experiment with a burning candle. Place a glass jar or bell jar over a lit candle, ensuring that the jar is airtight. As the candle burns, it consumes oxygen from the air inside the jar. Eventually, the candle flame will go out due to the lack of oxygen, proving that air (specifically oxygen) is necessary for burning.

4. To show that air occupies space, you can perform a simple experiment using a plastic bottle or syringe. Fill the bottle or syringe with water, ensuring there are no air bubbles. Then, cover the opening tightly and try to compress the air inside. You will find that it is not possible to compress the air significantly, indicating that air occupies space.

5. To prove that air has weight, you can use a sensitive balance or scale. Weigh an airtight container or balloon, and then fill it with air. The weight of the container or balloon with the added air will be greater than its initial weight, demonstrating that air has weight.

6. Air is useful to us in various ways. Three points highlighting the importance of air are:

7. Three properties of air include:

Air exerts force in various ways. For example, air pressure allows objects like airplanes to fly by providing lift. Air resistance or drag opposes the motion of objects moving through the air, creating a force that can affect their speed and trajectory.

8. Four effects of air pollution include:

9. Causes of pollution:

10. Two control measures for air pollution include:

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The oxidation number of Ag in Ag2O is +1.

In Ag2O, there are two silver atoms (Ag) and one oxygen atom (O). Oxygen is known to have an oxidation number of -2 in most compounds. Since the compound is neutral, the sum of the oxidation numbers of all the atoms must equal zero.

Therefore, the oxidation numbers of the two silver atoms must add up to +2 to balance out the -2 oxidation number of the oxygen atom. Since there are two silver atoms, each silver atom must have an oxidation number of +1 to yield a total oxidation number of +2 for the compound.

In Ag2O, the silver atoms lose one electron each to form Ag+ ions. This results in an oxidation number of +1 for each silver atom. The oxygen atom gains two electrons from the silver atoms to achieve a stable octet configuration, resulting in an oxidation number of -2 for the oxygen atom. The compound Ag2O is formed through the transfer of electrons, with each silver atom exhibiting an oxidation number of +1.

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Answer:

A

Explanation:

I sad A because water is changeable doesn't have fixed shape or volume water depend on the area or the temperature or other things .

The percent yield is 74.4 %.

Fe₃O₄ + 4H₂ → 3Fe + 4H₂O

First, calculate the theoretical yield of H₂O.

Theor. yield =

0.112 g H

2

×

1 mol H

2

2.016 g H

2

×

4 mol H

2

O

4 mol H

2

×

18.02 g H

2

O

1 mol H

2

O

=

1.001 g H

2

O

Now calculate the percent yield.

% yield =

actual yield

theoretical yield

×

100

%

=

0.745 g

1.001 g

×

100

%

=

74.4

%

The mass in grams (theoretical yield) of hydrogen is produced is considered to be 0.119 g H2.

Since

Mass of Mg = 31.3 g

Mass of H2O = 2.12 g

First, we have to determine the mole

So,

Mole of Mg = mass of Mg / molar mass of Mg

= (31.3 g ) / (24.30 g/mol )

= 1.28 mole

And,

Mole of H2O = (2.12g ) / (18.01g /mol )

= 0.117 mole

As per the chemical reaction:

2 mole of H2O react with 1 mole of Mg

So, 0.117 mole of H2O will react with mole of Mg is

Now

= ( 1 mol Mg / 2 mol H2O ) * 0.117 mol H2O

= 0.058 mole of Mg

Now

1 mole of Mg produce , 1 mole of H2

So,

0.058 mole of Mg will produce 0.058 mole of H2

Now, determine the mass of H2

= Molar mass of H2 * mole of H2

= 2 * 0.058

= 0.116 g

= 0.119

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Density = mass/Volume    or    D = m/V  

Given:  V = 22.3 gal

           D = 0.8206 g/mL

1)  Rearrange the equation to solve for m

2)  Find conversion factor(s) and convert V from gal to mL (by dimensional analysis) so the units cancel

3)  Solve for m in g

4)  Find conversion factor(s) and convert m from g → lbs

1)  D = m/V  rearranges to  m = D ∗ V

2)  1 gal = 3.785 L  and  1 L = 1000 mL;     22.3 gal  ∗  3.785  L/1 gal  ∗  1000 mL/1 L   =  84 406 mL

3)  m =  0.8206 g/mL  ∗  84 406 mL    =  69 260 g

4)  1 lb = 453.6 g;   69 260  g  ∗  1 lb/453.6 g   =  153 lbs

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Answer:

11318 feet and 10.771 inches

Explanation:

there is 3280.84 in one Km

just do 3280.84x3.45