What do you call a way of acquiring knowledge through experiment?

a.Academic method C.Scientific method

b.Experimental method d.Scientific notation ​

The enthalpy change, ΔH of the process:  A → C + E  is -125 kJ.

The enthalpy change of a reaction is the sum of the heat changes that occur as reactants combine to form products.

The enthalpy change of the reaction is given by the following formula:

The delta H for the process A → C + E is given as follows;

1. A ─→ B ΔH = ─100 kJ

2. B ─→ C + D ΔH = ─50 kJ

3. E ─→ D delta H = ─25 kJ

-3. D → E = +25 kJ

A → C + D = 1 + 2 + (- 3)

A → C + E = (- 100 - 50 + 25) kJ

A → C + E = -125 kJ

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Oxidation takes place at the anode. Reduction takes place at the cathode. Oxidation takes place on the left and recution takes place on the right.

The standard cell notation for an electrolytic cell with alumium and gold electrodes:

To determine which metal undergoes oxidation and which undergoes reduction we use the standard cell potentetial of the metals. Au is the stronger oxidising agent of the two and so it is likely to undergo reduction and so the Al will undergo oxidation.

Answer: A

The first column represent the alkali metal, the second column represent alkaline earth metals, the 3rd horizontal middle block is d block, the right 6 columns of the periodic table represent p block and the rightest column is noble gas.

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Answer: You need to research what ever you are working on and find 2 examples.

Explanation:

Combination. Option E is correct.

Given the chemical reaction between carbon and oxygen expressed as:

From the equation, you can see that carbn combines with oxygen atom to produce carbonmonoxide. This type of reaction is known as the combination reaction since it involves the reaction of two elements to produce a compound (carbon monoxide)

Based on the explanations above, we can concude that the reaction of carbon with oxygen to produce carbon monoxide is an example of a combination reaction.

The enthalpy of formation (ΔH°) of the given chemical reaction is equal to -905.3 KJ/mol.

The standard enthalpy of formation is defined as the change in enthalpy when one mole of a substance is formed from its pure elements under the standard state (1 atm of pressure and 298.15 K).

The standard enthalpy of formation is the energy released or absorbed when one mole of a substance is formed from its constituents under standard conditions. The symbol of the standard enthalpy of formation is represented by  [tex]\triangle {H^o_f}[/tex].

The equation for the standard enthalpy change of formation  for a balanced chemical reaction is shown below,

ΔH° (reaction)  =  ∑ [ΔH° of (products)− ∑ ΔH° of (Reactants)]

The standard enthalpy of the formation of fluorine gas = 0

The standard enthalpy of the formation of iodine gas = 62.23 KJ/mol

The standard enthalpy of the formation of IF₅ = -843 KJ/mol

ΔH° (reaction)  = - 843 - 62.23 = - 905 .3 KJ/mol

Therefore, the enthalpy of formation (ΔH°) of the given chemical reaction is -905.3 KJ/mol.

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This alkyl halide can be prepared by electrophilic addition of HBr to 2 different alkenes because of alkenes undergo hydrogenation in presence of acid and base when HBr can added to the different alkyl 3-methyl-hex-2-ene, 3-methyl-hex-3-ene and 3-methylene hexane

Hydrogenation is the chemical reaction in which molecular hydrogen and another compound and element usually in presence of catalyst such as nickel, palladium or platinum and this process is commonly employed to reduce or saturated organic compound

Addition of hydrogen and halogen to the double bond or triple bond based on markovnikov rule of addition and when HBr is added to CH3- CH=CH2 then Br is added to CH group and H is added to the CH₂ group of the alkene and if the reaction is carried in the presence of any peroxide then reverse addition is taking place

Then different alkyl structure such as 3-methyl-hex-2-ene, 3-methyl-hex-3-ene and 3-methylene hexane and image is given below

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Answer:

The student changed too many variables.

Answer:A

Explanation:because i did the test

Component Q is more powerful in explaining a scientific phenomenon because peer conformation and support are characteristics of a theory.

Scientific phenomena are events that can be witnessed in the natural and artificial worlds that make people wonder and pose questions. A theory is a logical interpretation or explanation of a phenomenon or set of occurrences. For instance, the theory of evolution through natural selection is a hypothesis because it explains the variety of life on earth.

In addition to offering accurate explanations or interpretations, theories also serve additional objectives. Here, we examine three additional goals of theories: the organizing of well-understood phenomena, the forecasting of outcomes in novel circumstances, and the development of fresh lines of inquiry.

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Answer

a. Increasing the air pressure on the solution.

Explanation

Based on the kinetic molecular theory, the statements that are true of the gas particles are as follows:

The Kinetic Molecular Theory is the theory that molecules of a gas are in constant random motion colliding with one another and with the wall of their container.

These collisions between the gas molecules are perfectly elastic and are responsible for the pressure of gas molecules.

The higher the kinetic energy of the gas molecules, the higher the temperature of the gas.

The kinetic molecular theory explains the physical state of gases since gas molecules have negligible intermolecular forces.

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Complete question:

Imagine the movement of gas particles in a closed container. According to the kinetic molecular theory, which statements below are true of the gas particles? Check all that apply. Gas particles act like tiny, solid spheres. Gas particles are in constant, random motion. Gas particles at lower temperatures move faster. Collisions are elastic, there is no energy lost as the particle hits the sides of the container. Slower moving particles collide more often and with more force with the container.

The mass in grams of the 254 mL of the liquid, given that it has a density of 1.24 g/cm³ is 314.96 grams

We'll begin by listing the out the parameters obtained from the question. This is given below:

The mass of the liquid can be obtained as follow:

Density = mass / volume

Cross multiply

Mass = Density × Volume

Mass of liquid = 1.24 × 254

Mass of liquid = 314.96 grams

Thus, the mass of the liquid is 314.96 grams

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The atomic radius of boron atom is 0.09nm

What is an atomic radius?

Atomic radius, also known as atomic radii, is the total distance between an atom's nucleus and its electron's outermost orbital.

Atomic radius is thus defined as: The  distance from the nucleus's center to the edge of its surrounding electron shells.

The radius of an atom is comparable to a circle's radius. The electron's most distant orbital is likened to the circle's outside edge, and the nucleus to the circle's center. The position of the outermost electron is unclear, making it challenging to calculate the atomic radii.

According to the question,

1m = 10-9nm

So, 9*10-11m = 0.09nm

The atomic radius of boron atom is 0.09nm

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The pH of a solution that is 0.67 M in sodium fluoride and 0.43 M in hydrofluoric acid is 8.53

The pH of a solution is the negative logarithm of the hydrogen ion concentration of the solution.

Mathematically:

The pH of the given solution is calculated as follows:

Ka of HF = 7.2 * 10⁻⁴

Also, Kw = Ka * Kb

Kw = 1.0 * 10⁻¹⁴

Kb = 1.0 * 10⁻¹⁴ / 7.2 * 10⁻⁴

Kb = 1.39 x 10⁻¹¹

The [OH¯] is calculated using the Kb expression:

Kb = [OH⁻] * [H⁺] / [HA}

[OH⁻] = [H⁺] = x

Kb = x² / (0.83 - x)

Assuming x is negligible, the denominator = 0.83

x = √(1.39 x 10⁻¹¹ * 0.83)

x = 3.39 * 10⁻⁶

pOH = -log (3.39 * 10⁻⁶)

pOH = 5.47

pH = 14 - 5.47

pH = 8.53

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Answer:

E, C, A, 90, 5, D, B, D, D, D and B, A C and E, A, E

Explanation:

1. is correct, it is E
2. is C, not D. D is when the liquid is freezing/when the solid is melting.
3. the answer is A. B is when the gas is condensing or when the liquid is boiling.
4. 90 temperature units. This is the boiling point. Technically the substance can still condense below this point until 5 temperature units, or D, but ignore that.
5. 5 temperature units.
6. D, this is where the solid and liquids exchange states (ie melting/freezing)
7. B, this is where boiling and condensing occurs
8. Crystallisation is a fancy word for freezing. The melting and freezing points are the same, so D
9. D. Fusion means freezing.
10. D and B.
11. A, C, and E
12. A has the highest temperature and the highest kinetic and potential energy
13. E has the lowest kinetic and potential energy

Answer:

In this reaction, Ca(OH)2 is a reducing agent. It reacts with hydrogen chloride to form calcium chloride and water. Therefore, the following reaction shows that matter is neither created nor destroyed in a chemical reaction: Ca(OH)2 + 2HCI -> CaCl2 + 2H20. The formation of calcium chloride and water from the hydrolysis of calcium hydroxide is not an example of matter being created or destroyed in a chemical reaction because it does not involve the breaking down of any bonds between atoms.

Explanation:

You can see that NO₂⁻ has an oxidation number of -1 and V³⁺ has an oxidation number of +3.

When we state the chemical formula of these compounds, we need to have that the algebraic sum of the oxidation numbers must be zero. In this case, we have that the sum is -1 + 3 = 2, it is incorrect because we need to have the result of zero.

For this problem, we can multiply three times NO₂⁻ obtaining that the oxidation number is -3, so the algebraic sum would be: (-1)(3) + 3 = -3 + 3 = 0. This means that the chemical formula will have three times NO₂⁻ bonded with V³⁺ and it would be:

The amount of work (in J ) is involved in a chemical reaction if the volume decreases from 4.25 to 1.97 L against a constant pressure of 0.838 atm is: 8.78 Joules.

The work done by an object can be calculated by multiplying the force acting on it by the perpendicular distance covered by the physical object. Also, the work done during a chemical reaction can be determined by multiplying the change in volume by the accompanying level of pressure.

Mathematically, the work done by a system is given by the formula:

Work done = PΔV = P(V₂ - V₁)

Where:

Substituting the given parameters into the formula, we have;

Work done = 0.038(4.25 - 1.97)

Work done = 0.038(2.28)

Work done = 0.08664 L.atm

Next, we would convert L.atm to Joules:

Work done = 101.325 × 0.08664

Work done = 8.78 Joules.

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The amount, in grams, of C that can form from the reaction, is 0.7414 g.

From the equation of the reaction, the mole ratio of A to that of C is 5:6.

In other words, for every 5 moles of A that reacts, 6 moles of C is produced.

Molar mass of A = 146.70 g/mol

Molar mass of C = 21.31 g/mol

Recall that: mole = mass/molar mass

Mole of 4.253 g of A = 4.253/146.70

                                  = 0.029 mol

From the mole ratio, the equivalent mol of C that will be produced is:

             0.029 x 6/5 = 0.03479 mol

mass = mole x molar mass

Mass of 0.03479 mol of C = 0.03479 x 21.31

                                            = 0.7414 g (to the appropriate sig. fig.)

In other words, the amount of C that will be produced from 4.253 g of A will be 0.7414 g.

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Answer

The new volume = 0.503 L or 503 mL

Explanation

Given:

Initial volume, V₁ = 480 mL = (480/1000) = 0.480 L

Initial temperature, T₁ = 45.0°C = (45 + 273 K) = 318 K

Final temperature, T₂ = 60.0°C = (60 + 273 K) = 333 K

What to find:

The new volume, V₂ when the temperature increases to 60.0°C.

Step-by-step solution:

Since the pressure is constant, the new volume, V₂ can be calculated using Charle's law formula.

Plugging the values of the given parameters into the formula, we have

The new volume, V₂ when the temperature increased to 60.0°C = 0.503 L or (0.503 x 1000 mL) = 503 mL

The advise which would be given to the engineers is for them to determine the limiting reactant so water will not be in excess.

This is referred to as the reactant which is completely used up in a chemical reaction and it helps to determine when the reaction stops. In this scenario, either water, lemon juice or sugar is a limiting reactant.

The best option in this scenario is to tell the engineers to determine the limiting reactant so  as to ensure that the quality of lemonade made is maximized and is therefore the right choice.

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Any substance made of matter is by definition a chemical, which includes solids, liquids, and gases. Pure substances or mixtures of substances can both be found in chemicals. Water (H2O), for example, is a pure chemical because the same molecules and molecular combinations are present throughout its whole structure.

Any material with a known composition is a chemical. Some chemicals, like water, are found in nature, meaning they always consist of the same "stuff." Other chemicals, including chlorine, are produced (used for bleaching fabrics or in swimming pools).

A chemical compound is a material that contains a specific combination of atoms or ions. Chemical compounds are made up of two or more elements coming together through a chemical process. While all substances are compounds, not all substances are compounds.

On its list of substances covered by the Toxic Substances Control Act, the EPA has more than 85,000 chemicals listed.

Not all chemicals are detrimental to the economy.

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Answer:

Moles of Ca3(PO4)2 = 0.455 M * 0.125 L = 0.0569 mol

1 Mole of Ca3(PO4)2 = 3 moles of Ca2+ ions

Thus, moles of Ca2+ ion = 3 * 0.0569 = 0.1707 ~ 0.171 moles

The number of moles of ions in a solution can be calculated using the molarity and volume of the solution. The number of moles of Ca ²⁺ ions contained in 0.125 L of 0.455 M solution of Ca₃ (PO₄) ₂ is 0.0170 moles.

Molarity is a term used to represent the concentration of the solution. Mathematically it is the ratio of number of moles of solute to the volume of solution in liters.

The molarity of the calcium phosphate solution is given 0.455 M  and its volume is 0.125 L. Thus, the no.of moles of calcium phosphate in the solution is calculated as follows:

no.of moles of Ca₃ (PO₄) ₂  = molarity × volume

                                             = 0.455 M  × 0.125 L

                                             = 0.0568 moles.

It is clear from the formula that one mole of calcium phosphate contains 3 moles of Ca ²⁺ ions. Therefore,  the number of moles of calcium ions in 0.0568 moles of calcium phosphate is calculated as follows:

No. of moles of Ca ²⁺ ions  = 0.0568 × 3

                                            = 0.0170 moles.

Hence the number if moles of calcium ions in 0.125 L of 0.455 M calcium phosphate is 0.0170 moles.

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The change in enthalpy of the gas mixture during the reaction is - 95 kj.

The formula for the change in internal energy is given by:

ΔU = ΔH + W

ΔU = the change in inter energy = -181 kj ( decreased)

ΔH = the change in enthalpy

W = work done =  -86 kj

substituting the values in the formula we get :

ΔU = ΔH + W

- 181 kj = ΔH  - 86 kj

ΔH = -181 kj + 86  kj

ΔH = - 95 kj

Measurements show that the energy of a mixture of gaseous reactants decreases by 181.kj during a certain chemical reaction, which is carried out at a constant pressure. Furthermore, by carefully monitoring the volume change it is determined that -86.kj of work is done on the mixture during the reaction. The change in enthalpy of the gas mixture during the reaction is - 95 kj.

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Potassium oxide is an ionic compound formed by combining potassium and oxygen. It carries the chemical formula K2O.

So, this is expected product from the reaction of potassium with oxygen because of the following:

To get the net charge of the compound equal to zero, we need to satisfy the equation K2O. So that's the answer.

• According to the balanced equation, we have :

4 Fe(s) + 3 O2(g) → 2 Fe2O3(s)

4 x 55.85g of Fe reacts with 3 x 32g of Oxygen

Given 17.86 g of Ion, we want to find out how much oxygen will be required in this instance .

• So :

M.mass Fe: 4* 55.85 = 223.4

M.mass O2 : 3* 32 = 96

we can rearrange by :

223.4 → 96

17.86 → x .....(cross multiply )

223.4x = 96* 17.86

x = (96 *17.86) / 234.4

x = 7.314

• Therefore mass of oxygen required = 7.3g ,



Answer:

Species. A population is a group of plants or animals of the same species that live in an area.

Answer

Explanation

Note that a mole of any substance has 6.02 x 10²³ atoms of that substance.

Let x represent the mole of magnesium present in 5.01 x 10²² atoms of magnesium.

Therefore,

Cross multiply, and divide both sides by 6.02 x 10²³ atoms to get x

Answer:By combining two or more substances, a mixture is produced. A homogeneous solution tends to be identical, no matter how you sample it. Homogeneous mixtures are sources of water, saline solution, some alloys, and bitumen. Sand, oil and water, and chicken noodle soup are examples of heterogeneous mixtures.

Explanation: