8. What does the term 'sustainable mean? *

​

Answer:

jhhhhhhhhh

Explanation:

dffffffffffffg

Answer:

Rust forms on iron filings faster than on a large iron block

Explanation:

Because the surface area exposed to air in the refrigerator is greater than its area by mass, the rust-forming reaction occurs faster.

Answer:

35.75 days

Explanation:

From the given information:

For first-order kinetics, the rate law can be expressed as:

[tex]\mathsf{In \dfrac{C}{C_o} = -kt}[/tex]

Given that:

the rate degradation constant = 0.12 / day

current concentration C = 0.05 mg/L

initial concentration C₀ = 3.65 mg/L

[tex]\mathsf{In( \dfrac{0.05}{3.65})= -(0.12) t}[/tex]

㏑(0.01369863014) = -(0.12) t

-4.29 = -(0.12)

t = -4.29/-0.12

t = 35.75 days

Answer:

the Rhyniognatha hirsti

Explanation:

at age 400 million years old

Answer:

B - The high temperature makes the gas molecules spread apart according to Charles's law because this law describes how a gas will behave at constant pressure.

Explanation:

Charle's Law describes the relationship between temperature and volume, where increased temperature leads to increased volume. When volume is increased, that means the gas molecules are more spread apart and have more random motion. Therefore, the answer is B.

The high temperature causes the gas molecules to spread apart according to Charles's law because explain how a gas, behave at constant pressure.

The physical principle called Charles' law which  states that the volume of a gas equals a constant value many by its temperature as measured on the Kelvin scale.

Volume regaled by a clinched amount of gas is directly proportional to its temperature and pressure if remains steady.

Thus, option "B" is correct, the volume of a gas equals a constant value.

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Answer: pH = 2,897 , basic[tex][H+][OH-] = 10^{-14} ==> [H+] = \frac{10^{-14}}{7,89*10^{-12} } =\frac{1}{789} \\pH= -lg([H+]) = 2,897 \\pH<7 ==> basic[/tex]

Explanation:

Answer: The set of quantum numbers for the electrons in Be atom are (2, 1, -1, 1/2), (1, 0, 0, 1/2), (1, 0, 0, -1/2) and (2, 0, 0, -1/2)

Explanation:

There are 4 quantum numbers:

Berylium (Be) is the 4th element of periodic table having electronic configuration of [tex]1s^22s^2[/tex]

For first electron:

[tex]n=1\\l=0\text{ (for s-subshell)}\\m=0\\s=+\frac{1}{2}[/tex]

For second electron:

[tex]n=1\\l=0\\m=0\\s=-\frac{1}{2}[/tex]

For first electron:

[tex]n=2\\l=0\text{ (for s-subshell)}\\m=0\\s=+\frac{1}{2}[/tex]

For second electron:

[tex]n=2\\l=0\text{ (for s-subshell)}\\m=0\\s=-\frac{1}{2}[/tex]

Hence, the set of quantum numbers for the electrons in Be atom are (2, 1, -1, 1/2), (1, 0, 0, 1/2), (1, 0, 0, -1/2) and (2, 0, 0, -1/2)

Answer:

Q was < K. Partial pressure of hydrogen decreased, iodine increased

Explanation:

After iodine was added the Q was [Select] K so the reaction shifted toward the Products [Select] ,The partial pressure of hydrogen [Select], Iodine [Select] |,and hydrogen iodide Decreased

Based on the equilibrium:

H2(g) + I2(g) ⇄ 2HI(g)

K of equilibrium is:

K = [HI]² / [H2] [I2]

Where [] are concentrations at equilibrium

And Q is:

Q = [HI]² / [H2] [I2]

Where [] are actual concentrations of the reactants.

When the reaction is in equilibrium, K=Q.

But as [I2] is increased, Q decreases and Q was < K

The only concentration that increases is [I2], doing partial pressure of hydrogen decreased, iodine increased

Answer:

C. 2.70 g/mL

Explanation:

Density is the ratio between the mass of a substance and the volume it occupies. Based on Archimedes' volume, the displaced volume of the aluminium is the volume it occupies. To solve this question we must find the difference in volume between initial volume of water = 30mL and final volume of water + aluminium = 39.26mL. This difference is the volume of the aluminium. With its mass we can find density:

39.26mL - 30mL = 9.26mL

Density = 25.00g / 9.26mL =

2.70g/mL

Right answer is:

Answer:

Sound travels through the air in approximately 332 metres per second?

Explanation:

is this what you are looking for>

Answer: The amount of heat needed to melt the given amount of octane is 84.6 kJ

Explanation:

We know:

Boiling point of Octane = [tex]125.6^oC[/tex]

Few processes involved are:

(1): [tex]C_8H_{18} (s) (-57^oC, 219K) \rightleftharpoons C_8H_{18}(s) (-57^oC, 219K[/tex]

(2): [tex]C_8H_{18}(l) (-57^oC, 219K) \rightleftharpoons C_8H_{18}(l) (99.2^oC,372.2K)[/tex]

Calculating the heat absorbed for the process having same temperature:

[tex]q=n\times \Delta H_{(f)}[/tex] ......(i)

where,

q is the amount of heat absorbed, n is the moles of sample and [tex]\Delta H_{(f)}[/tex] is the enthalpy of fusion

Calculating the heat released for the process having different temperature:

[tex]q=n\times C_{l}\times (T_2-T_1)[/tex] ......(ii)

where,

n = moles of sample

[tex]C_{l}[/tex] = specific heat of liquid

[tex]T_2\text{ and }T_1[/tex] are final and initial temperatures respectively

The number of moles is defined as the ratio of the mass of a substance to its molar mass.

The equation used is:

[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex] ......(3)

Given mass of octane = 160. g

Molar mass of octane = 114.23 g/mol

Plugging values in equation 3:

[tex]\text{Moles of octane }=\frac{160.g}{114.23g/mol}=1.40 mol[/tex]

We are given:

[tex]n=1.40mol\\\Delta H_{fusion}=20.740 kJ/mol[/tex]

Putting values in equation (i), we get:

[tex]q_1=1.40mol\times 20.470kJ/mol\\\\q_1=28.658kJ[/tex]

We are given:

[tex]n=1.40mol\\C=255.68J/mol^oC\\T_2=99.2^oC\\T_1=-57^oC[/tex]

Putting values in equation (ii), we get:

[tex]q_2=1.40mol\times 255.68J/mol^oC\times (99.2-(-57))\\\\q_2=55912.10J=55.912kJ[/tex]

Calculating the total amount of heat released:

[tex]Q=q_1+q_2[/tex]

[tex]Q=[(28.658)+(55.912)]kJ=84.6kJ[/tex]

Hence, the amount of heat needed to melt the given amount of octane is 84.6 kJ

Answer: 88 grams

Explanation:

Answer:

Solubility indicates the maximum amount of a substance that can be dissolved in a solvent at a given temperature. Such a solution is called saturated. Divide the mass of the compound by the mass of the solvent and then multiply by 100 g to calculate the solubility in g/100g .

Solubility of solute:

To calculate the solubility in g/100g:

Solubility of NaNO₃=[tex]\frac{21.9g*100g}{25 g} =87.6[/tex]

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Answer:

The more concentrated acetic acid buffer has a better buffer capacity because requires more moles of acid or base to change the pH than a more diluted acetic acid buffer.

Explanation:

Buffer capacity is defined as the moles of an acid or base that are needed to change the pH of a buffer in 1 unit.

A more concentrated solution of acetic buffer contains more moles of the acid per liter of solution. A solution that contains more moles of the acetic ion or the acetic acid requires more moles of base or acid to change the pH, that means:

The more concentrated acetic acid buffer has a better buffer capacity because requires more moles of acid or base to change the pH than a more diluted acetic acid buffer.

Answer:

See explanation and image attached

Explanation:

The reaction between benzophenone and phenylmagnesium bromide is a Grignard reaction.

A Grignard reagent is any alkyl magnesium halide compound. In this case, the Grignard reagent is phenylmagnesium bromide.

Reaction of Grignard reagent with a ketone yields all alcohol. Thus, the reaction of benzophenone with phenylmagnesium bromide yields triphenyl methanol.

The mechanism of the reaction and all electron movements are shown in the image attached to this answer.

Answer:

.094 M

Explanation: 0.32molNaCl/ 3.4L = .094M

Answer: The correct option is A) a nitrogen molecule.

Explanation:

Polar covalent molecules are defined as chemical compounds in which the difference in electronegativity between the atoms is not equal to 0. These molecules are formed by heteronuclear molecules.

Heteronuclear molecules are defined as the molecules which are formed by the combination of more than one type of atom having a different nucleus.

Non-polar covalent molecules are defined as chemical compounds in which the difference in electronegativity between the atoms is equal to 0. These molecules are formed by homonuclear molecules.

Homonuclear molecules are defined as the molecules which are formed by the combination of one type of atom having the same nucleus.

From the given options:

It is a homonuclear molecule formed by the combination of 2 nitrogen atoms

It is a heteronuclear molecule formed by the combination of 1 nitrogen and 1 oxygen atoms

It is a heteronuclear molecule formed by the combination of 2 nitrogen and 1 oxygen atom and has some dipole moment. Thus, is considered a polar molecule

It is a heteronuclear molecule formed by the combination of 1 nitrogen and 2 oxygen atoms and has some dipole moment. Thus, is considered a polar molecule

Hence, the correct option is A) a nitrogen molecule.

Answer:

maybe it's c. An endothermic reaction

An endothermic reaction is a chemical reaction that absorbs heat. Therefore, the correct option is option C.

An endothermic reaction in thermochemistry would be any thermodynamic process that results in a rise in the system's enthalpy H (or heat capacity U). A closed system typically helps to absorb thermal energy from the surroundings during such a process, which causes heat transfer through into system.

It could be a physical process, like the melting of ice cubes, or a chemical process, like the dissolution of ammonium nitrate (NH[tex]_4[/tex]NO[tex]_3[/tex]) throughout water (H[tex]_2[/tex]O).  An endothermic reaction is a chemical reaction that absorbs heat.

Therefore, the correct option is option C.

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Answer:

The equation: (NH₄)₂SO₄ = 2NH4(+) + SO4(-2)

The number of moles = 5 g / 132.14 g/mol = 0.038 mol

The number of molecules = 0.038 X 6.022x10^23 = 2.29x10^23

the number of positive ions present in the ammonium sulphate solution:

2 positive ions for every 1 molecule of (NH₄)₂SO₄

so 2 x 2.29x10^23 = 4.58x10^23

the number of negative ions present in the ammonium sulphate solution

1 negative ion for every 1 molecule of (NH₄)₂SO₄

so 1 x 2.29x10^23 = 2.29x10^23

the total number of ions present in the ammonium sulphate solution​

4.58x10^23 + 2.29x10^23 = 6.87x10^23

Answer:

H

Explanation:

try not to put your hands on him

Answer:

Wearing goggles or other eye protection will remove the risk or danger for these students

Explanation:

Soft contact lenses are usually worn in the eyes and Ammonia compound may fog the lens thereby retaining the particles of ammonia which could spread to the eye and cause a lot of damage to it.

Using a goggle is usually more effective in dealing with the risks involved as they prevent the Ammonia from having any contact at all with the eyes due to the far proximity to the eyes when compared to contact lenses.

Answer:

Constitutional Isomers

Explanation:

Constitutional isomers can be regarded as structural isomers ,these are compounds that have the same molecular formula with different structural formulas. Example is Butane and isobutane; both compound posses the same molecular formula(C4H10) with different structural formulas. compounds of Constitutional isomers are differ in term of connectivity, which

is the way the constituent atoms are been connected to another. It should be noted that Constitutional Isomers Share the same molecular formula but have different connectivity of atoms and different physical properties.

Answer:

Talc powder suspended in air

Answer:

B

Explanation:

C and D is correct

To be clear that electrochemical is science that study the exchange conversion of chemical energy and electric energy through redox reaction

As c is salt bridge

And d is electrochemical define

A is correct as the electricity transfer in electric wire not in solution so its B) un correct

The statement which is not true about the electrochemical cell is option B, the metals that form the electrodes cannot be identical.

In an electrochemical cell, two different metals or metal ions are typically used as the electrodes. These electrodes are placed in separate compartments, which contain the reaction solutions and are connected by a salt bridge or porous membrane.

During the cell's operation, electrons flow through an external wire or circuit, from the anode (where oxidation occurs) to the cathode (where reduction occurs), and nonparticipating ions flow through the salt bridge or porous membrane to maintain charge neutrality.

An oxidation-reduction reaction must occur to generate an electrical potential difference between the two electrodes, driving the flow of electrons through the external circuit. Therefore, options A, C, and D are true for an electrochemical cell. Hence, B is incorrect.

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Answer:

Chlorine gas reacts with potassium bromide to form potassium chloride in solution and liquid bromine.

Answer:

DDDDD

Explanation:

Answer:

The maximum theoretical percent recovery from the recrystallization of 1.00 g of benzoic acid from 15 mL of water = 94.9%

Note: The question is incomplete. A similar but complete question is given below:

The solubility of benzoic acid in water is 6.80g per 100mL at 100 degrees C and 0.34 g per 100mL at 25 degrees C.

Calculate the maximum theoretical percent recovery from the recrystallization of 1.00 g of benzoic acid from 15 mL of water, assuming the solution is filtered at 25 degrees C.

Explanation:

Solubility of benzoic acid in water at 100 degrees C = 6.80g per 100mL

Solubility of benzoic acid in water  at 25 degrees C =  0.34 g per 100mL

Mass of benzoic acid to be theoretically recovered from 100 mL of water = 6.80 g - 0.34 g = 6.46 g

At 25 degrees;

0.34 g of benzoic acid is present in 100 mL of water

x g of  benzoic acid will be present in 15 mL of water

x = 0.34 × 15 / 100 = 0.051 g

Mass of benzoic acid to be theoretically recovered from 25 mL of water = 1.00 g - 0.051 g = 0.949 g

Maximum theoretical percent recovery = (mass recovered / original mass dissolved) x 100%

Maximum theoretical percent recovery =  (0.949 / 1.00) × 100% = 94.9 %

Therefore, the maximum theoretical percent recovery from the recrystallization of 1.00 g of benzoic acid from 15 mL of water = 94.9%

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Answer:

5Atm

Explanation:

I just guess and it’s right

Answer:

[tex]1 {s}^{2} 2 {s}^{2} 2 {p}^{4} [/tex]

OR

[tex]2 : 6[/tex]

Answer:

If we look at the ground state (electrons in the energetically lowest available orbital) of oxygen, the electron configuration is [tex]1s^{2} 2s^{2} 2p^{4}[/tex] . If the element were to become excited, the electron could occupy an infinite number of orbitals. However, in most texts, the example will be the next available one. So for oxygen, it might look like this:  [tex]1s^{2} 2s^{2} 2p^{3}3s^{1}[/tex]  - where the valence electron now occupies the 3s orbital in an excited (i.e. not ground) state.

So, the electron configuration of oxygen in its excited state​ is [tex]1s^{2} 2s^{2} 2p^{3}3s^{1}[/tex].

Answer:

?

Explanation: