Which statement best describes the use of a chemical indicator in a titration?

A. It must be measured to the nearest 0.01 mL.

B. It must be colored in the acid solution.

C. It must measure pH directly at all pH values.

D. It must change color near the equivalence point.​

Only reactions B and C would be spontaneous at 298 K.

Spontaneous reactions are reactions that occur naturally and do not require external energy input to proceed. This can be determined by calculating the Gibbs free energy of the reaction at a given temperature and pressure. Gibbs free energy can be calculated using the equation ΔG = ΔH - TΔS, where ΔH is the enthalpy change of the reaction, ΔS is the entropy change of the reaction, T is the temperature in Kelvin, and ΔG is the change in free energy of the reaction.
A spontaneous reaction will have a negative ΔG, meaning that the reaction is exergonic and releases energy. Therefore, the products of the reaction are more stable than the reactants. If ΔG is positive, the reaction is endergonic and requires energy input to proceed.
In order to determine which of the following reactions would be spontaneous at 298 K, we must calculate the ΔG of each reaction and determine if it is positive or negative. The reactions are:
A. 2H2O(l) → 2H2(g) + O2(g) ΔH = 484 kJ/mol, ΔS = 69.9 J/K mol
B. CO2(g) + H2(g) → CO(g) + H2O(g) ΔH = 41 kJ/mol, ΔS = -102.6 J/K mol
C. Fe2O3(s) + 2Al(s) → Al2O3(s) + 2Fe(l) ΔH = -850 kJ/mol, ΔS = -243 J/K mol
To calculate ΔG at 298 K, we will use the equation ΔG = ΔH - TΔS. The temperature in Kelvin is 298 K, or 25°C.
A. ΔG = (484,000 J/mol) - (298 K) x (69.9 J/K mol) = +4165 J/mol (positive, non-spontaneous)
B. ΔG = (41,000 J/mol) - (298 K) x (-102.6 J/K mol) = -2874 J/mol (negative, spontaneous)
C. ΔG = (-850,000 J/mol) - (298 K) x (-243 J/K mol) = -42600 J/mol (negative, spontaneous)

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Answer:

Phosphorus(P) and Oxygen(O)=Covalent bond

Chlorine(Cl) and Sodium(Na) = Ionic bond

Silver (Ag) and Silver (Ag)= Metallic bond

The environmental conditions of the ocean are:

In our oceans, there are known to be a lot of environmental conditions that are known to often affect the growth, survival and also the productivity of marine organisms. These are the ones listed above.

Note that the increased concentration of chemicals, e.g.  nitrogen and phosphorus is one that can be harmful to marine life.

Hence, The environmental conditions of the ocean are:

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Answer:

5.73498*10^13

Explanation:

............

a) 2.00 L of 18.5 M H2SO4, concentrated sulfuric acid

Sulfuric acid is a strong mineral acid commonly used in industrial settings for a variety of purposes. It is a colorless, odorless, oily liquid that is highly corrosive and reacts violently with many organic and inorganic materials.

Number of moles = Molarity x Volume

                      = 18.5 M x 2.00 L

                      = 37.0 moles

Mass of the solute = Number of moles x Molar Mass

                      = 37.0 moles x 98 g/mol

                      = 3,646 g

b) 100.0 mL of 3.8 X 10^-6 M NaCN, the minimum letal concentration of sodium cyanide in blood serum.

Number of moles = Molarity x Volume

                      = 3.8 x 10^-6 M x 0.100 L

                      = 3.8 x 10^-8 moles

Mass of the solute = Number of moles x Molar Mass

                      = 3.8 x 10^-8 moles x 49 g/mol

                      = 1.86 x 10^-7 g

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Answer: B. Ketone

Explanation: Another name for acetone is propanone, and it is the main ketone as it has the functional group in the middle, a CH3 on each side. Ketones have the C=O functional group.

Answer:

+26.6kJ/mol

Explanation:

The enthalpy of dissolution of NH₄NO₃ is:

NH₄NO₃(aq) + ΔH  → NH₄⁺ + NO₃⁻

Where ΔH is the heat of reaction that is absorbed per mole of NH₄NO₃,

The moles that reacts in 1.60g are (Molar mass NH₄NO₃:80g/mol):

1.60g * * (1mol / 80g) = 0.02 moles reacts

To find the heat released in the coffee cup calorimeter, we must use the equation:

Q = m×ΔT×C

Where Q is heat released,

m is mass of the solution

ΔT is change in temperature (Final temperature - Initial temperature)

C is specific heat of the solution (4.18J/g°C)

Mass of the solution is:

1.60g + 75g = 76.60g

Change in temperature is:

25.00°C - 23.34°C = 1.66°C

Replacing:

Q = m×ΔT×C

Q = 76.60g×1.66°C×4.18J/g°C

Q = 531.5J

This is the heat released per 0.02mol. The heat released per mole (Enthalpy change for the dissolution of NH₄NO₃) is:

531.5J / 0.02mol = 26576J/ mol =

+26.6kJ/mol

+ because the heat is absorbed, the reaction is endothermic-

Yes, that statement is generally correct. A scientific law is a statement that describes a phenomenon or pattern in nature, often expressed mathematically, without attempting to explain why it occurs. A scientific theory, on the other hand, is a well-substantiated explanation for a set of phenomena, based on empirical evidence and scientific reasoning.

A scientific law summarizes what happens in a particular situation, often in the form of an equation or formula, whereas a scientific theory attempts to explain why it happens.

For example, the law of gravity describes the attraction between masses, but it does not explain why this attraction occurs. In contrast, the theory of general relativity attempts to explain the underlying principles of gravity, including its effects on the curvature of space-time.

It's worth noting that both scientific laws and scientific theories are based on empirical evidence, but they serve different purposes in scientific inquiry. Laws describe what happens in a particular situation, while theories attempt to explain why it happens.

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Answer:

Volume = 3.4 L

Explanation:

In order to calculate the volume of CO₂ produced when 15.2 g of CaCO₃ is heated, we need to first write out the balanced equation of the thermal decomposition of CaCO₃:

CaCO₃ (s) + [Heat] ⇒ CaO (s) + CO₂ (g)

Now, let's calculate the number of moles in 15.2 g CaCO₃:

mole no. = \(\mathrm{\frac{mass}{molar \ mass}}\)

                 = \(\frac{15.2}{40.1 + 12 + (16 \times 3)}\)

                 = 0.1518 moles

From the balanced equation above, we can see that the stoichiometric molar ratios of CaCO₃ and CO₂ are equal. Therefore, the number of moles of CO₂ produced is also 0.1518 moles.

Hence, from the formula for the number of moles of a gas, we can calculate the volume of  CO₂:

mole no. = \(\mathrm{\frac{Volume \ in \ L}{22.4}}\)

⇒ \(0.1518 = \mathrm{\frac{Volume}{22.4}}\)

⇒ Volume = 0.1518 × 22.4

                 = 3.4 L

Therefore, if 15.2 g of CaCO₃ is heated, 3.4 L of CO₂ is produced at STP.

There are numerous ways to determine whether lead is present in an ore. Atomic absorption spectroscopy is a popular approach. With this method, an ore sample is dissolved in acid and then atomized in a flame or plasma.

The sample's atoms will absorb light at particular wavelengths that are peculiar to the element under investigation. The amount of light absorbed can be used to calculate how much lead is present in the sample. Inductively coupled plasma mass spectrometry and X-ray fluorescence spectroscopy are further techniques. It is crucial to remember that these procedures call for specialized tools and training, thus they ought to only be carried out in a lab by qualified experts.

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ANSWER

Single displacement reaction ---- Option A

EXPLANATION

Given that;

In the reaction above, Chlorine displaced bromine, this is possible because chlorine is more reactive than bromine.

The above reaction is an example of a single displacement reaction.

Single displacement reaction is a type of reaction in which an element displaces another element in the compound to produce a new compound and the displaced element.

Hence, the correct answer is option A

\(\qquad \qquad\huge \underline{\boxed{\sf Answer}}\)

This reaction is called decomposition reaction, furthermore it can be said to be decomposition of limestone.

The balanced chemical equation for the reaction is ~

\(\qquad \sf  \dashrightarrow \: CaCO_3 = CaO + CO_2\)

Answer:

The answer is B, in this case.

Explanation:

An isomer is a molecule with the same number of atoms as another compound, but they differ in arrangement of the atoms.

Answer:

The amount of work required to raise the TV from point A to point B is equal to the amount of gravitational potential energy the TV gains from its height above the ground. This is generally true for any object ...

Answer: the cells that make the lung tissue have mutated DNA

Explanation: I JUST DID THE ASSIGNMENT !!!

Answer: 1st Question C 2nd Question A and D

Explanation:

so u dont gotta look up the other one

The final broth temperature will be approximately 38.4°C.

When mixing two substances with different temperatures, we can use the principle of conservation of energy. The energy lost by the hot substance (broth) is equal to the energy gained by the cold substance (water), assuming no energy is lost to the surroundings. This can be expressed using the equation:

Q_lost = Q_gained

The energy lost by the broth can be calculated using the formula:

Q_lost = m_broth * c_broth * (T_final - T_initial)

where m_broth is the mass of the broth, c_broth is its specific heat capacity, T_final is the final temperature, and T_initial is the initial temperature of the broth.

Similarly, the energy gained by the water can be calculated using:

Q_gained = m_water * c_water * (T_final - T_initial)

Since the two substances reach thermal equilibrium, we can set Q_lost equal to Q_gained:

m_broth * c_broth * (T_final - T_initial) = m_water * c_water * (T_final - T_initial)

Plugging in the given values and solving for T_final, we find that the final temperature of the broth is approximately 38.4°C.

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The solution is supersaturated from the solubility curve shown.

A solubility curve is a graphical representation of the relationship between the solubility of a substance and temperature. It shows how the solubility of a solid solute (e.g., salt, sugar) changes with temperature in a given solvent (e.g., water).

A solubility curve is typically plotted with solubility on the y-axis and temperature on the x-axis. The curve generally slopes upward, meaning that as the temperature increases, the solubility of the solute in the solvent also increases. This is because higher temperatures increase the energy of the solvent and solute particles, making it easier for them to dissolve and form a homogeneous solution.

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Missing parts:

When 50 grams of potassium chloride KCI is dissolved in 100 grams of water at 50 C the solution can correctly be described as

A unsaturated

B saturated

C supersaturated

Answer:

Explanation:

a) The balanced equation for the double replacement reaction between lead (II) nitrate and potassium bromide is:

Pb(NO₃)₂(aq) + 2KBr(aq) → PbBr₂(s) + 2KNO₃(aq)

In this reaction, lead (II) bromide (PbBr₂) will precipitate, while potassium nitrate (KNO₃) will remain in solution.

b) To determine the amount of precipitate produced, we need to first determine the limiting reactant. We can do this by calculating the number of moles of each reactant and comparing it to the stoichiometry of the balanced equation.

The molar mass of lead (II) nitrate is 331.21 g/mol and the molar mass of potassium bromide is 119.00 g/mol.

The number of moles of lead (II) nitrate is 32.5 g / 331.21 g/mol = 0.0981 mol The number of moles of potassium bromide is 38.75 g / 119.00 g/mol = 0.3256 mol

According to the balanced equation, one mole of lead (II) nitrate reacts with two moles of potassium bromide to produce one mole of lead (II) bromide. This means that if all the lead (II) nitrate were to react, it would require 0.0981 mol * 2 = 0.1962 mol of potassium bromide.

Since we have more than enough potassium bromide (0.3256 mol > 0.1962 mol), lead (II) nitrate is the limiting reactant.

The number of moles of lead (II) bromide produced will be equal to the number of moles of lead (II) nitrate consumed, which is 0.0981 mol.

The molar mass of lead (II) bromide is 367.01 g/mol, so the mass of lead (II) bromide produced will be 0.0981 mol * 367.01 g/mol = 36.0 g.

c) To determine the amount of excess reactant remaining, we need to subtract the amount consumed from the initial amount.

The number of moles of potassium bromide consumed is half the number of moles of lead (II) nitrate consumed, which is 0.0981 mol / 2 = 0.04905 mol.

The mass of potassium bromide consumed is 0.04905 mol * 119.00 g/mol = 5.84 g.

The mass of potassium bromide remaining is 38.75 g - 5.84 g = 32.91 g.

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The structure of fatty acids involves long carbon-based chains with a carboxyl group (―COOH) located in the end, triglycerides phospholipids contain a phosphate group and glycerol, while steroids are cyclic and they contain C atoms linked via 4 fused rings.

Lipids are a broad category of biomolecules that include fatty acids, triglycerides phospholipids, and steroids. For example, fatty acids are long carbonated chains that contain exactly identical CH2 groups in the interior of the molecule and a carboxyl group (―COOH) located at one extreme side.

Triglycerides phospholipids are composed of three fatty acids chains linked to a glycerol backbone and also a phosphate group that may confer polar properties to the molecule.

Finally, steroids are another important class of lipids composed of several carbon-based fused rings.

Therefore, we can conclude that fatty acids, triglycerides phospholipids, and steroids are structurally different lipids that are mainly composed of carbon-based structures.

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Answer: sexual  reproduction results to the offspring having a mix of genetic characteristics of the parents. Where as Asexual offspring tend to look like their parent.  

Explanation:

Intercourse leads to the mixing of genetic material. Asexual reproduction is often the parent making a separate copy of themselves.

We have to write the net ionic equation for the reaction between HCl and NaHCO₃.

The molecular equation will show us the products of this equation.

Molecular equation:

HCl (aq) + NaHCO₃ (aq) ------> NaCl (aq) + CO₂ (g) + H₂O (l)

Now we can split this compounds into their ions to get the total ionic equation:

Total ionic equation:

H+ (aq) + Cl- (aq) + Na+ (aq) + HCO3- (aq) ----> Na+ (aq) + Cl- (aq) + CO₂ (g) + H₂O (l)

And finally we can identify the spectator ions. The ones that we have on both sides, they are Na+ and Cl-. We can cancel them out.

Net ionic equation:

H+ (aq) + HCO3- (aq) ----> CO₂ (g) + H₂O (l)

Answer: H+ (aq) + HCO3- (aq) ----> CO₂ (g) + H₂O (l)

Answer:

It's True.

Explanation:

Matter is anything that has mass and takes up space. Mass gives an object the property of weight and inertia (resistance to change in the motion of an object). There are four states of matter, solid, liquid, gas, and plasma.

Answer:

The number of these organisms in the soil would decrease.

Explanation:

\(K_{sp}\) of the compound is found to be  5.04 ×\(10^{-10}\).

Solubility :Solubility can be define as the amount of a substance that dissolves or mixes in a given amount of solvent at specific conditions.

Solubility equilibrium

Ksp = \([A^{+} ]^{a}\) \([B^{-} ]^{b}\)

Ksp = solubility product constant

A+ = cation in an aquious solution

B- = anion in an aqueous solution

a, b = relative concentrations of a and b

Given,

Solubility = s = 3.60 × \(10^{-2}\) g/L

molar mass = 288 g/ mol

∴ s= 3.60 × \(10^{-2}\) g/L ÷ 288 g/ mol = 1.25 ×\(10^{-4}\) mol/ L

Reaction:

MX3 ⇄ M + 3X

           s       3s

\(K_{sp}\) =[ \(M^{+3}\)] [ \(X^{-1}\)\(]^{3}\) = solubility product

∴ \(K_{sp}\) =\([s]^{} [3s]^{3}\)

∴ \(K_{sp}\) = 3 \(s^{4}\)

∴ \(K_{sp}\) = 3 × (3.60 × \(10^{-2}\) \()^{4}\)

∴ \(K_{sp}\) = 503.8848 ×\(10^{-8}\)  = 5.04 ×\(10^{-10}\)

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Answer:

170.38g is the mass of 1 mole of C₁₂H₂₆

Explanation:

To solve this question we must find the molar mass of the alkane C₁₂H₂₆. The molar mass is defined as the mass of one mole of a substance.

In 1 mole of C₁₂H₂₆ we have 12  moles of Carbon and 26 moles of Hydrogen. With the periodic table of elements we can know the molar mass of 1 mole of Carbon and 1 mole of hydrogen, and, thus, the molar mass of the alkane (Molar mass C = 12.01g/mol, H = 1.01g/mol)

Molar mass C₁₂H₂₆:

12C = 12*12.01g/mol = 144.12g/mol

26H = 26*1.01g/mol = 26.26g/mol

144.12g/mol + 26.26g/mol =

Answer: 212

Explanation:

Answer:

D

Explanation:

The rest have characteristics of a plant cell

Use these cubes to answer the questions below. The cubes contain the same quantity (same number of moles) of gas at the same temperature. The gases have similar structures and similar molecular weights 1st attempt

1. Which cube will have the greatest pressure?

A: The cube with the smallest volume will have the greatest pressure. This is due to the ideal gas law, which states that pressure is proportional to the number of gas particles and inversely proportional to the volume. So, if the number of gas particles is constant and the temperature is constant, a decrease in volume will result in an increase in pressure.

2. Which cube will have the smallest volume?

A: The cube that is compressed the most will have the smallest volume. The volume of a gas is directly proportional to its temperature and inversely proportional to its pressure. So, if the temperature is constant and the pressure increases, the volume will decrease.

3. Which cube will have the highest temperature?

A: If the cubes contain the same quantity of gas, the temperature will be the same in all cubes. The temperature of a gas is proportional to the average kinetic energy of its particles. Since the number of particles and their total kinetic energy are constant, the temperature will remain constant.

A cube is a three-dimensional figure which is box shaped and has six square faces which meet each other at right angles. It has eight vertices and 12 edges.

Formula :

where "a" is equal to ''Area''

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