Which of the following describes a chemical change?
A. a suspension of corn starch and water
B. formation of a precipitate
C. formation of a solution
D. filtration of a solid from a liquid

Answer:

x/2

Explanation:

X = 2 molecules of H2

For 2 molecules of H2, there's only 1 molecule of O2. Meaning, there's twice the amount of H2, so O2 = x/2 molecules.

I hope I'm understanding this question right.

The change in temperature (∆T) if 500 J of heat are added to a 23 g sample of silver is calculated to be 90.58°C.

The change in temperature of a substance can be calculated using the following formula:

Q = mc∆T

Where;

500 = 23 × 0.24 × ∆T

500 = 5.52∆T

∆T = 500/5.52

∆T = 90.58°C

Therefore, the change in temperature (∆T) if 500 J of heat are added to a 23 g sample of silver is calculated to be 90.58°C.

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Answer: Most metalloids have some physical properties of metals and some of non-metals. So metalloids are similar to metals and non-metals.

Aluminium (Al) is a better conductor of electricity than Boron (B) which is a non-metal.

HAZWOPER training and certification recognize:

The correct option is both A and C

HAZWOPER (Hazardous Waste Operations and Emergency Response) training and certification recognize that a large number of victims (as much as 80%) in hazardous waste incidents or emergencies will self-present or be self-referred for medical treatment.

Additionally, HAZWOPER training acknowledges that victims may use any entrance they can access at a hospital, not just the emergency department entrance.

This is because individuals affected by hazardous materials may arrive at different areas of the hospital seeking medical assistance.

Therefore, option d. Both A and C are correct statements regarding the recognition of HAZWOPER training and certification.

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The chemical formula for the molecule you provided is C2H5Cl.

In the molecule, the central atom is carbon (C), which is bonded to two hydrogen atoms (H) and one chlorine atom (Cl). The carbon atom forms single bonds with each of the hydrogen and chlorine atoms, resulting in a linear structure.

To write the chemical formula, we start by indicating the number of atoms of each element present in the molecule. In this case, there are two carbon atoms (C2), five hydrogen atoms (H5), and one chlorine atom (Cl1).

Next, we write the symbols for the elements in the order of their appearance. The formula is typically written with the carbon atom first, followed by hydrogen, and then any other elements in alphabetical order. Therefore, the chemical formula for the molecule is C2H5Cl.

The subscripts in the formula indicate the number of atoms of each element in the molecule. In this case, there are two carbon atoms, five hydrogen atoms, and one chlorine atom.

It's important to note that the formula represents the simplest ratio of atoms in the molecule. It does not provide information about the spatial arrangement or bonding pattern of the atoms. Additional structural information, such as the arrangement of atoms in space, would require a more detailed representation, such as a Lewis structure or a three-dimensional model.

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Covalent compounds are held together with an intra molecular attraction which is weaker than metallic bond

hence covalent compounds exist as liquids, gases and soft solids

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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Answer:

\(\boxed {\boxed {\sf C. \ 4}}\)

Explanation:

First, define some important terms.

We know the mass number is 9. So, the sum of protons and neutrons is 9.

We also know the atoms has 5 neutrons. Therefore, the rest must be protons.

Subtract the 5 neutrons from the overall mass number of 9.

There are 4 protons, so the atomic number is also 4. This atom is beryllium.

Answer:

A. The reaction shifts to the right (products) and the concentrations of I and H₂ decrease.

Explanation:

If gas is removed from the system at equilibrium, the system will try to compensate for the loss by shifting the reaction in a direction that produces more gas molecules. This is known as Le Chatelier's principle, which states that a system at equilibrium will respond to a disturbance by shifting in a way that minimizes the effect of the disturbance.

In this case, since gas is being removed from the system, the reaction will shift to the side that produces more gas molecules. Looking at the balanced equation, we can see that 2HI(g) has a greater number of gas molecules compared to H₂(g) and I₂(g). Therefore, the system will shift to the right (products) to produce more HI(g) and reestablish equilibrium.

Answer:

will be 9.7 Liters

Explanation:

Answer:

the answer is

2,1,1,1

Explanation:

The standard change in Gibbs free energy for the reaction at 25 °C is 278.0 kJ/mol  for the given enthalpy of reaction .

The Gibbs free energy (or Gibbs energy as the preferred name; symbol G) is a thermodynamic potential that can be used to calculate the maximum amount of non-volume expansion work that a thermodynamically closed system can perform at constant temperature and pressure. It also serves as a prerequisite for processes like chemical reactions that may place under these conditions. The Gibbs free energy is denoted by the symbol G(p,T) = U+pV-TS = H-TS, where p denotes pressure, T denotes temperature, U denotes internal energy, V denotes volume, H denotes enthalpy, and S denotes entropy.

A thermodynamic quantity equal to a system's entire heat content. It is equivalent to the system's internal energy plus the product of pressure and volume.

According to the table, the standard Gibbs free energy of formation values are;

Fe₂O₃ (s) = -822.1 kJ/mol

Al₂O₃ (s) = -1675.2 kJ/mol

Al (s) = -1477.7 kJ/mol

Fe (s) = 0 kJ/mol

The reaction is:

Fe₂O₃ (s) + 2 Al (s) → Al₂O₃ (s) + 2 Fe (s).

Therefore, the standard change in Gibbs free energy for the reaction at 25 °C is:

AG = -822.1 kJ/mol + (2 x -1477.7 kJ/mol) - (-1675.2 kJ/mol) - (2 x 0 kJ/mol) = 278.0 kJ/mol

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Answer:

If the primary predator of a prey species is eliminated, the prey species’ population will increase to the point of overpopulating the ecosystem. This overpopulation will result in depletion of the prey species’ food supplies as more individuals compete for the same resources and can ultimately lead to the prey species starving.

Explanation:

Elimination of a predator from an ecosystem might lead to famine amongst its prey species because:

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Answer

The Balanced reaction is: Fe₂O₃ + 3C → 2Fe + 3CO

The grams of iron (Fe) produced = 48.96 grams.

Explanation

Given:

Mass of Fe₂O₃ used = 70.0 grams

What to find:

The grams of iron (Fe) produced.

Step-by-step solution:

The balanced reaction between iron(III) oxide and pure carbon in a blast furnace to produce molten iron metal and carbon monoxide is:

Fe₂O₃ + 3C → 2Fe + 3CO

The next step is to convert 70.0 grams of Fe₂O₃ to moles using the mole formula

Now, we can use the moles of Fe₂O₃ and the mole ration from the equation above to determine the moles of Fe produced.

Finally, we can convert 0.876698603 mol Fe to mass in grams as follows

The grams of iron (Fe) produced is 48.96 grams.

The activation energy of this reaction is approximately -13.770 J/mol.

1. To graphically determine the activation energy, we need to plot two points. The given data points are:

  Point 1: (1, -1.275)

  Point 2: (2, 0.379725)

2. The rise is the change in the y-coordinate between the two points:

  Rise = y2 - y1 = 0.379725 - (-1.275) = 1.654725

3. The run is the change in the x-coordinate between the two points:

  Run = x2 - x1 = 2 - 1 = 1

4. The slope of the line formed by these two points can be calculated using the formula:

  Slope = rise / run = 1.654725 / 1 = 1.654725

5. The activation energy (Ea) can be determined using the equation:

  Ea = -R * slope

 Here, R is the ideal gas constant, which is approximately 8.314 J/(mol·K).

6. Plugging in the values:

  Ea = -8.314 * 1.654725 = -13.770 J/mol

Note that the activation energy is negative because it represents the energy difference between the reactants and the transition state (higher energy) in an exothermic reaction.

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Answer:

option a. iron,copper, aluminium.

Answer:

An atom is the smallest particle of an element that still has the properties of that element. Atoms, in turn, are composed of subatomic particles, including negative electrons, positive protons, and neutral neutrons. The number of protons in an atom determines the element it represents.

Explanation:

The smallest possible particle of an element is a atom. The remainder is made up of a cloud of negatively charged electrons around a positively charged nucleus made up of protons and neutrons.

The smallest unit of matter that may be split without producing electrically charged particles is the atom. It is also the smallest piece of substance with chemical element-like characteristics. Electric forces, which link electrons towards the nucleus of atoms, cause them to be drawn to any positive charge.

Space makes up the majority of an atom. The remainder is made up of a cloud of negatively charged electrons around a positively charged nucleus made up of protons and neutrons. Compared to electrons, that are the smallest charged particles in nature, the nucleus is tiny and dense.  

Therefore, the smallest possible particle of an element is a atom.

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Answer:

0.641 g of Nitrogen are present in the mixture.

Explanation:

We use the Ideal Gases Law, to solve this question.

For the mixture:

P mixture . V mixture = mol mixture . R . T

We convert the T° to K →  23°C + 273 = 296 K

R = Ideal gases constant → 0.082 L.atm/mol.K

1 atm . 2L = mol mixture . 0.082 L.atm/mol.K  . 296K

2 atm.L / ( 0.082 mol /L.atm) . 296 = 0.0824 moles

We know that sum of partial pressure = 1

Partial pressure N₂ + Partial pressure O₂ = 1

1 - 0.722 atm = Partial pressure N₂ → 0.278 atm

We apply the mole fraction concept:

Partial pressure N₂ / Total pressure = Moles N₂ / Total moles

Moles N₂ = (Partial pressure N₂ / Total pressure) . Total moles

Moles N₂ = (0.278 atm / 1 atm) . 0.0824 mol → 0.0229 moles

We convert the moles to mass → 0.0229 mol . 28 g/mol = 0.641 g

641 mg

At pOH value  of 6.0 the pH value of the following solution is 8.0 and the concentration of [\(H^{+}\) ] ion is \(10^{-8}\)

In this question we will apply the formula

      pH +pOH = 14 . . . . . . . . . . . . .(1)

where pH = concentration of [\(H^{+}\) ] ion

pOH = concentration of [\(OH^{-}\) ] ion

As per the question

pOH =6.0

Putting the value of pOH in equation (1) we get the value of pH

              pH + 6.0 =14

             pH = 14 -6.0

             pH  = 8.0

 The value of pH if the pOH value is 6.0 is 8.0

To find the concentration of \(H^{+}\) ion we will use the following formula

This is calculated by the formula

                                 [\(H^{+}\)} = \(10^{-pH}\)

where we will write the values of pH

Hence the concentration of [\(H^{+}\)} ion is \(10^{-8}\)

Therefore at  pOH of 6.0 the pH value of the following solution is 8.0 and the concentration of [\(H^{+}\) ] ion is \(10^{-8}\)

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The complete question is -

What is the pH value and concentration of [\(H^{+}\) ] ion of the following if the pOH value of the solution is 6.0 ?

There are 1000 g in one kg. It is a correctly reflect the relationship between SI units and units containing decimal prefixes.

What is meant by SI units?

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Answer:When a single compound breaks down into two or more compounds or elements in a chemical reaction then it is known as decomposition reaction.

The chemical symbol for sodium carbonate is .

The decomposition of sodium carbonate is:

The decomposition of sodium bicarbonate,  will result in the formation of sodium oxide,  and carbon dioxide, .

Hence, carbon dioxide,  will produce with sodium oxide,  on decomposition of .

Explanation:Na2CO3 Na2O +CO2   CO2 is the answer

Answer:

The molar mass is 138.8843 g/mol 

Answer:

Mass= 351.5kg

Explanation:

From the question

mole = 9.25mol.

Molar mass = C2H6 = 16×2+1×6=32+6=38molg.

Mass = ?

\(n = \frac{mass}{moler \: mass} \)

\(9.25 = \frac{m}{38} \\ = 9.25 \times 38 = m \\ = 351.5kg\)

therefore mass is 351.5kg

Answer:

Endothermic is something that needs heat added into it, while exoteric gives heat off

Explanation:

1. Endo(Melting ice)

2. Endo(heat enters the system)

3. Exothermic(making ice)

4. Endothermic( liquid to gas)

5. Exothermic(campfire)

6. exothermic(gas to a liquid)

7. Exothermic (the flame of a candle)

8. Exothermic (heat leaves the system)

9. I don’t know if photosynthesis is exo or endothermic

The carrying capacity of the area was reduced in the year 10 according to the graph that shows the number of foxes on the island over a span of 15 years.

The graph shows a population of foxes over a span of 15 years. The y-axis represents the number of foxes on the island, while the x-axis represents time. The study began with the earlier 0 and ran until the start of year 15. According to the graph, the carrying capacity of the area was reduced in the year 10.

In the graph, it is shown that the population of foxes on Sunday Gill island had a significant increase from year 0 to year 3. After year 3, the fox population started to decrease and then remained fairly constant until year 10. After year 10, the population of foxes on the island started to decline more rapidly until the end of the study in year 15

This decline in the population of foxes on the island is most likely due to the reduction in carrying capacity of the area. Carrying capacity refers to the maximum number of individuals that an environment can sustain. When the carrying capacity of an environment is reached, it means that the environment can no longer provide the necessary resources to sustain the population.  

There are various factors that can cause a reduction in carrying capacity, such as environmental degradation, competition for resources, or a natural disaster. In this case, it is not clear what caused the reduction in carrying capacity in year 10, but it is likely that it was due to some environmental factor that impacted the availability of resources for the fox population.
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Answer: methane

Explanation:

Answer:

If n = 4, then the possible values of 1 and m depend on the equation or expression being used. Without more information, it is impossible to determine what the possible values of 1 and m might be. Can you please provide more context or information about the problem you are trying to solve?

Answer:

I think the answer is 12.0107 u and 6 (6 as the atomic number) and (12.0107 u as the atomic mass).

Explanation:

I Hope this helps.

The heat required is 2347 J

The heat required for a change of state depends on the substance, the amount of the substance, and the specific change of state involved.

When a substance undergoes a change of state, such as melting or boiling, heat is added or removed to cause the particles in the substance to gain or lose energy and rearrange themselves into a new physical state. The amount of heat required to effect this change is known as the heat of transformation, or the heat of fusion

We know that;

H1 = 25.0 *  0.235 * (962 - 950)

= 70.5 J

H2 = 25 g * 88 J/g

= 2200 J

H3 = 25 * 0.278  * (972 - 962)

=76. 5 J

Then we have that;

70.5 J + 2200 J + 76. 5 J

=2347 J

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