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Answer: the answer is B estimation

Explanation:

i just took a test

The one that is represented by the number of significant figures in a quantity is scientific notation. The correct option is D.

Scientific notation is a method of expressing numbers that are either too large or too small to be written in decimal form.

In the United Kingdom, it is known as scientific form, standard index form, or standard form.

The proper scientific notation format is an x 10b, where an is a number or decimal number with an absolute value greater than or equal to one and less than ten, or 1 |a| 10. b is the power of ten required for scientific notation to be mathematically equivalent to the original number.

Scientific notation is represented by the number of significant figures in a number.

Thus, the correct option is D.

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Answer:

The Kₐ of the weak acid is 1.033×10⁻⁴

Explanation:

The dissociation of a weak acid in aqueous solution is limited to about 5 to 10%

The acid dissociation reaction is given as follows;

HA (aq) + H₂O (l) → H₃O⁺(aq) + A⁻ (aq)

Given that the pH = 2.5, we have

pH = -log₁₀[H₃O⁺] = 2.5

∴ [H₃O⁺] = 10^(-2.5) = 0.0031623

[tex]K_a = \dfrac{[H_3O^+][A^-]}{[HA]}[/tex]

Kₐ = [H₃O⁺][A⁻]/[HA] = (0.0031623^2)/(0.1 - 0.0031623) = 1.033×10⁻⁴

The acid dissociation constant, Kₐ for weak acid is very low as obtained

Answer:

Yes, at 20 °C the tank was filled to full capacity

Explanation:

Given;

let initial pressure, P₁ = 2.37 atm

let initial volume, V₁ = 1860 L

let final pressure, P₂ = 220 bar = 217.123 atm

let final volume, V₂ = ?

Subject the air volume (1860 L )  at 2.37 atm to the tank rating (220 bar)

Ideal law is given by;

PV = nRT

At a fixed mole and gas temperature, the equation becomes;

P₁V₁ = P₂V₂

V₂ = (P₁V₁) / P₂

V₂ = (2.37 x 1860) / 217.123

V₂ = 20.3 L

After subjecting the air volume to tank rating, the volume of the air at 220 bar is 20.3 L which is greater than tank volume (18 L).

The extra 2.3 L can be assumed to be compressed gas volume due to the given (lower) temperature.

Thus, at 20 °C the tank was filled to full capacity.

Explanation:

astronomers have discover that in general the future of a Galaxy is, the more redshift light is this mean that the further away the Galaxy are the faster they are moving this is similar to explosion where the bits moving fastest travel for furthest on the explosion redshift data provides evidence that the universe including space itself is expanding .

Answer:

C₅H₁₂ + 8O₂ → 5CO₂ + 6H₂O

Explanation:

Let's start by counting how many molecules we have on each side.

Reactants

C - 5

H - 12

O - 2

Products

C - 1

O - 3

H - 2

We have to balance both sides. Since we have 5 carbon atoms on the reactants side and 1 carbon atom on the products side, we'll start with that. Write 5 as the coefficient for CO₂ to balance the carbons.

C₅H₁₂ + O₂ → 5CO₂ + H₂O

Now that the carbons are balanced, let's look at the hydrogens. There's 12 on the reactants side and 2 on the products side. To balance the hydrogens, we have to write 6 as the coefficient for H₂O.

C₅H₁₂ + O₂ → 5CO₂ + 6H₂O

Now the hydrogens are balanced. All that's left to do is balance the oxygens. Let's start by counting how many atoms we have on each side.

Reactants

C - 5

H - 12

O - 2

Products

C - 5

H - 12

O - 16

So, to balance the number of atoms on both sides, write 8 as the coefficient for O₂.

C₅H₁₂ + 8O₂ → 5CO₂ + 6H₂O

Lastly, let's check to make sure everything is balanced.

Reactants

C - 5

H - 12

O - 16

Products

C - 5

O - 16

H - 12

Both sides are balanced. Therefore, the balanced chemical equation is: C₅H₁₂ + 8O₂ → 5CO₂ + 6H₂O.

Hope that helps.

Answer:

[tex]\boxed{C_{5}H_{12} + 8O_{2} -->5CO_{2} + 6H_{2}O}[/tex]

Explanation:

Part 1: Count the number of atoms on each side per element

To start, count the number of atoms per element on both sides of the equation.

Left Side

C - 5 atoms

H - 12 atoms

O - 2 atoms

Right Side

C - 1 atom

H - 2 atoms

O - 3 atoms

Part 2: Balance carbon atoms

Now, with this information, you can begin finding out how to properly balance both sides of the equation.

You need 5 carbon atoms on the left, so place a coefficient of 5 in front of the [tex]CO_{2}[/tex] product. This will balance the carbons. Do not place a coefficient in front of the [tex]C_{5}H_{12}[/tex] reactant - none are necessary!

Then, you can update your counts for your atoms.

Left Side

C - 5 atoms

H - 12 atoms

O - 2 atoms

Right Side

C - 5 atoms

H - 2 atoms

O - 11 atoms

The updated equation will look like this:

[tex]\boxed{C_{5}H_{12}+O_{2} --> 5CO_{2} + H_{2}O}[/tex]

Part 3: Balance hydrogen atoms

Now, balance the hydrogen atoms. Place a coefficient of 6 in front of the [tex]H_{2}O[/tex] product. This will balance the hydrogen atoms.

Once again, update the atom counts:

Left Side

C - 5 atoms

H - 12 atoms

O - 2 atoms

Right Side

C - 5 atoms

H - 12 atoms

O - 16 atoms

The updated equation will look like this:

[tex]\boxed{C_{5}H_{12} +O_{2}--> 5CO_{2} +6H_{2}O}[/tex]

Part 4: Balance oxygen atoms

To fully balance the equation, place a coefficient of 8 in front of the [tex]O_{2}[/tex] reactant. This will equalize the amount of oxygen atoms on both sides of the equation.

The updated equation will look like this:

[tex]\boxed{C_{5}H_{12} + 8O_{2} --> 5CO_{2} + 6H_{2}O}[/tex]

Part 5: Check the equation and atom counts

Now, update the atom counts one last time to make sure they are equal.

Left Side

C - 5 atoms

H - 12 atoms

O - 16 atoms

Right Side

C - 5 atoms

H - 12 atoms

O - 6 atoms

They are equal, so you may proceed.

Part 6: Check if reductions are necessary

If the equations coefficients can all be divided by a common divisor (i.e., 3), follow up with that step. However, any equation that has a reactant or product without a coefficient, skip this step entirely.

This equation falls into that category, so you may proceed past it.

Your final equation will look like this: [tex]\boxed{C_{5}H_{12} + 8O_{2} -->5CO_{2} + 6H_{2}O}[/tex]

Answer:

(b)

Explanation:

The 3s^2, 3p^6  orbitals form  -3 charge.

This is the element phosphorous and an example of a -3 ion is in aluminium phosphide, AlP3.

The electronic configuration which represents the element forming a simple ion having with a charge of -3 is; 1s², 2s², 2p⁶, 3s², 3p³. Option B is correct.

In this electronic configuration, the element has a total of 16 electrons. To form a simple ion with a charge of -3, the element needs to gain three electrons. This is achieved by adding three extra electrons to the existing configuration.

When the element gains three electrons, the electron configuration becomes:

1s², 2s², 2p⁶, 3s², 3p⁶

This configuration represents the stable octet configuration, where the element has a complete outer shell with eight electrons. Since the charge is -3, it means the element has gained three extra electrons to achieve a stable configuration.

Therefore, the correct electronic configuration representing the element that forms a simple ion with a charge of -3 is 1s², 2s², 2p⁶, 3s², 3p³

Hence, B. is the correct option.

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Answer:

Because Argon is a inert gas

Explanation:

Inert gases don't take place in any experiments

Answer:

Below.

Explanation:

The sodium reacts strongly with the chlorine to form NaCl and the heat of reaction continues the brightness, whereas it does not react with the inert gas  argon and soon cools down.

The number of protons and neutrons together makes the total atomic mass of the element. The atom of chromium has 28 neutrons. Thus, option b is correct.

An atomic mass is the property of an element that defines the number of protons and neutrons of the atom placed in a periodic table. The atomic mass is represented at the lower half of the atomic symbol.

The atomic mass is the sum of the neutrons and the protons that are held together in the nucleus of the atom as a concentrated mass. The atomic number is given as,

Atomic number = number of protons + number of neutrons

Given,

The atomic mass of chromium = 52

Number of protons = 24

Substituting values above:

52 = 24 + number of neutrons

number of neutrons = 52-24

= 28

Therefore, the number of neutrons of a chromium atom is 28.

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Answer: option b, 28

Answer:

A large point of evidence in this would be the rate of increase in how fast the polar ice caps are melting and the ocean is rising as a result. As the climate is getting warmer so are the oceans and this is causing the ice caps which are in the ocean.

Explanation:

Answer:

[tex]\boxed{\mathrm{Iodine}}[/tex]

Explanation:

Halogens are elements in group 17 or 7 in the periodic table.

Iodine is a halogen.

Therefore, iodine, an Halogen

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false,

sodium has a vigorous reaction with water.

This can be observed by putting a piece of sodium in water,

it moves swiftly across the surface of water and reacts violently.

Answer:

The metre is defined as the length of the path travelled by light in a vacuum in 1/299 792 458 of a second.

Answer:

balanced equation:

2Ca(NO3)2 (aq)-----> 2CaO (s) + 4NO2 (g) + O2 (g)

So heating 2 moles of Ca(NO3)2 gives 2 moles of CaO, 4 moles of NO2 and 1 mole of O2. This is a heat decomposition reaction. It gives a white precipitate (CaO), and brown pungent gas (NO2).

Answer:

The balanced equation of the reaction is below.

Explanation:

2Ca(NO3)2 -----> 2CaO + 4NO2 + O2.

Answer:

Chemical Changes are also called Chemical Reactions. Chemical reactions involve combining different substances. The chemical reaction produces a new substance with new and different physical and chemical properties. Matter is never destroyed or created in chemical reactions.

Explanation:

The single mark placed on the sidewalk by Julie has been acting as the reference point for detecting the motion of the snail. Thus, option D is correct.

The snail has been the shelled animal that has been mostly residing in the resting condition with limited movement. To evaluate the movement of the snail, there has been the consideration of a point that was the starting point from the movement.

The line that has been set across the sidewalk has been acting as the reference, and the distance traveled has been calculated from that point. Thus, option D is correct.

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Answer:

The correct option is;

The reaction pathway for the trials is different

Explanation:

The effect of a catalyst in a chemical reaction is to increase the rate of a reaction by changing the pathway or mechanism of the reaction and/or to lower the transition state's energy thereby lowering the activation energy of the reaction

The pathway of the reaction is changed by the catalyst by the formation of intermediate compounds by the catalyst which require lower activation energy to form the products than the original non-catalyzed reactants. In the process the catalyst is regenerated, thereby, not taking part in the reaction.

Answer:

b) 1s22s22p63s23p5

Explanation:

Answer:

b) 1s22s22p63s23p5

Explanation:

edge 2021

Answer:

0.020g de sulfato de plomo se requieren

La concentración de la solución diluida es de 3ppm

Explanation:

Las partes por millón (ppm) son definidas como:

miligramos soluto / 1L solución.

Si deseas preparar una solución a 100ppm de sulfato de plomo (II) necesitas 100mg de este sulfato en 1L. En 200mL = 0.200L vas a necesitar:

0.200L × (100mg / 1L) = 20mg de sulfato de plomo (II).

Como 1000mg = 1g,

20mg × (1g / 1000mg) = 0.020g de sulfato de plomo se requieren.

Ahora, se van a tomar 30mL de esta solución y se diluirán a 1000mL. Se diluye la solución:

1000mL / 30mL = 33.33 veces.

Como la solución inicial es de 100ppm, esta dilución genera una solución de concentración:

100ppm / 33.33 = 3ppm

Explanation:

pH is used to measure the concentration of H+ ions ([H+]) and therefore, whether a substance is acidic or basic (alkaline). Solutions with a pH of less than seven are acidic, while those with a pH greater than seven are basic (alkaline).

Answer:

greater than 7

Explanation:

A base is any solution with a pH greater than 7. A pH of 7 is considered neutral. For example, the pH of water. An acid is any solution with a pH less than 7.

Hope that helps.

[tex]7.408 \;X 10 ^ {-3} m^{-2} s^{-1}[/tex]  is rate of a reaction when k = 0.2, [A] = 3 M, [B] = 3 M, m = 1, n = 2 .

The rate at which the concentration of reactant or product participating in a chemical reaction alters is called the rate of reaction.

Rate of reaction = [tex]\frac{change \;in \;concentration}{time}[/tex] =  (mol/litre)/time.

m= 1 and n = 2

[tex]rate = K [A] [B]^2[/tex]

[tex]0.2 = K X 3 X 3 ^2[/tex]

K =   [tex]\frac{0.2 }{27 }[/tex]

K =   [tex]7.408 \;X 10 ^ {-3} m^{-2} s^{-1}[/tex]

Hence, [tex]7.408 \;X 10 ^ {-3} m^{-2} s^{-1}[/tex]  is rate of a reaction when k = 0.2, [A] = 3 M, [B] = 3 M, m = 1, n = 2 .

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Answer: 7.4 10-3

Explanation:

7.4 10-3 this is right ong

answer is 20

explanation: total Pressure = 205

partial pressure of N = 143

partial pressure of He = 41

total pressure = partial pressure of N + partial pressure of O + partial pressure of He

partial pressure of O = 205 - 185 = 20

Answer:

20

Explanation:

Answer:

The chemical bond between 2 molecules is called an intermolecular force.

Answer:

Chemical Bond:

Attraction between two atoms results in the formation of a bond which is called a chemical bond.

Inter molecular Forces:

Attractive Force that in between 2 molecules is called Inter molecular Forces. (Inter : Between)

Answer:

25 g

Explanation:

Mass percent implies the mass of solute dissolved in a solution

Mass percent = mass of solute/mass of solute + mass of solvent × 100/1

Since mass percent concentration= 20%

Mass of solvent = 100g

Let mass of solute = x

Hence;

20 = x/x +100 ×100/1

20/100= x/x + 100

0.2 = x/x + 100

0.2(x + 100) = x

0.2x + 20 = x

20 = x - 0.2x

20 = 0.8x

x= 20/0.8

x= 25 g

Answer:

The filament of a bulb has a high melting point because of the heat generated inside the bulb.

Explanation:

When electricity is concentrating and run through a bulb, it starts to generate heat. Leave it on long enough and it will start to build up a lot of heat. Have you ever tried touching a light bulb when it has been all day? It's scorching to the skin.

Since electricity generates heat, the bulb's filament has to have a high melting point so it doesn't melt, destroy the bulb, and leave you light-less. If the filament has a high melting point, then it is able to withstand heat generated by electricity and provide you light.

Answer:

Neutral substance is a substance that show no acid or base properties.

Explanation:

Neutral substance is a substances that show no acid or base properties, has an equal number of hydrogen and hydroxyl ions and does not change the color of litmus paper.

Answer:

They release no substance

Explanation:

Since the substance is neutral, nothing will be released from it.

Answer:

By giving electricity to copper compound solution.

Explanation:

Electrolysis is one of the major way of refined copper. The copper containing solution has two electrodes.i) positive electrodes called anode. ii) negative electrodes called cathode. When electricity is pass into the copper containing solution electrolysis process is starts and impure copper is formed in anode and pure copper is formed in cathode.

So, We can get pure copper in cathode through electrolysis.

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Answer:

See explanation

Explanation:

Charles law gives the relationship between volume and temperature of a gas. Charles law States that, the volume of a given mass of gas is directly proportional to its temperature at constant pressure.

Theoretically, it is assumed that when the absolute zero temperature has been achieved, the volume of any ideal gas will be found to be equal to zero. If the volume of the gas is zero, it now implies that all molecular motion will be stopped. This does not happen in real gases as all gases are found to condense to solids or liquids when this temperature is exceeded.

When volume is plotted against temperature, volume of the gas approaches zero at t = −273.15 °C, which is the x-intercept of the Charles law graph. Below this temperature, we can only get negative values of volume which does not exist hence, −273.15 °C is the lowest attainable temperature also known as the absolute zero.

Answer:

The acid solution is a concentrated solution.

Explanation:

Acetic acid is a weak acid, because it ionizes partially in water as shown below:

CH3COOH + H2O —> H3O+ + CH3COO-

A solution containing a larger quantity of acetic acid is termed concentrated solution.

This is so because a concentrated solution is a solution that contains more of the solute than the solvent.

A solute is the substance which dissolves in the solvent.

A solvent is the substance which dissolves a solute.

In this case, acetic acid is the solute and water is the solvent.

Solution is simply the combination of solute and solvent

Solution => Solute + Solvent

More solute + Less solvent => Concentrated solution

Therefore, a solution containing a higher quantity of acetic acid ( i.e the solute) in water (i.e the solvent) is called a concentrated solution.

Answer:

Here's what I get from one source.

Explanation:

[tex]\begin{array}{lc}\textbf{Source} &\textbf{Contribution \%} \\\text{Space heating }& 45\\\text{Water heating} &18\\\text{Space cooling} & 9 \\\text{Computers/Electronics} & 6 \\\text{Lighting} & 6 \\\text{Cooking} & 4 \\\text{Refrigeration} & 4 \\\text{Wet cleaning} & 3 \\\text{Other} & 5 \\\end{array}[/tex]

The pie chart is in the Figure below.

Answer:

oppositely charged ions in a chemical compound

Explanation:

Answer:

Between ions

Explanation: