The question is 22 I need help with

Answer:

Half life is 46 days

Explanation:

The half life of a radioactive substance can be predicted by:

Nt = No(1/2)^(t/th)

Nt is the amount remaining (mg)

No is the initial amount (mg)

t is the time elapsed, in days

th is the half life in days.

Nt = No(1/2)^(t/th)

0.50mg = (8.0mg)(1/2)^(184 days/th)

Using logs, we can solve this for th

th = 46 days

Answer:

Caustic soda

Explanation:

The fractional distillation of air is carried out on liquid air. Before air is liquified, the carbon dioxide content of air is removed using caustic soda. The air is then compressed to a pressure of about 200 atm, sudden expansion of the gas leads to cooling. The process continues until air becomes liquid at  -200°C.

Fractional distillation of liquid air usually produces nitrogen and oxygen as major products. nitrogen in obtained first since it has a lower boiling point than oxygen. The gases are then dried, compressed and stored in cylinders.

A 7.26 × \(10^{-2}\)  M aqueous solution of chromium(II) iodide, \(CrI_{2}\), is hypertonic to red blood cells.

1. Red blood cells are typically isotonic with solutions that have an osmolarity of approximately 0.3 Osm/L (300 mOsm/L), which corresponds to a 0.15 M NaCl solution.
2. To determine the osmolarity of the \(CrI_{2}\) solution, we must first identify the number of particles (ions) that will be released into the solution when it dissolves. In this case, one \(CrI_{2}\) molecule dissociates into one \(Cr^{2+}\) ion and two I- ions.
3. Next, multiply the molarity of the \(CrI_{2}\) solution (7.26×\(10^{-2}\) M) by the number of ions it dissociates into (1 + 2 = 3 ions). This gives us an osmolarity of 7.26×\(10^{-2}\) M × 3 = 2.178×\(10^{-1}\) Osm/L (217.8 mOsm/L).

4. Compare the osmolarity of the \(CrI_{2}\) solution to that of red blood cells (217.8 mOsm/L vs. 300 mOsm/L). Since the \(CrI_{2}\) solution has a higher osmolarity, it is hypertonic to red blood cells.

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1 mole of a gas at STP occupies 22.4 L volume

Now the volume is given =78.4 therefore,

No. of moles of gas = 78.4 ÷ 22.4 = 3.5 moles

I hope it helps you~

The pair that cannot be mixed together to form a buffer solution is: a) NaClO, HNO3.

A buffer solution is a solution that resists changes in pH when small amounts of an acid or a base are added. To form a buffer solution, you need a weak acid and its conjugate base, or a weak base and its conjugate acid.

In the given options:

a) NaClO, HNO3 - NaClO is a salt of a weak acid (HClO) and a strong base (NaOH), while HNO3 is a strong acid. Mixing a strong acid with the salt of a weak acid and a strong base does not form a buffer solution.

b) NH2CH3, HCl - NH2CH3 is a weak base, and HCl is a strong acid. When mixed together, they form the conjugate acid (NH3CH3+) of the weak base, which can act as a buffer.

c) HC2H3O2, NaOH - HC2H3O2 is a weak acid, and NaOH is a strong base. When mixed together, they form the conjugate base (C2H3O2-) of the weak acid, which can act as a buffer.

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Answer:

yes

Explanation:

Launching a projectile over a significant distance, such as several hundred miles, presents a range of complex challenges that must be carefully addressed. The success of achieving such a long range relies on accounting for various factors that influence the projectile's trajectory, including aerodynamics, atmospheric conditions, Earth's curvature, and external forces.

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The difference between two atoms of carbon having the same number of neutrons is in the number of protons present in their nuclei. The atomic number of carbon is 6, which indicates the number of protons in its nucleus. For instance, if there are two carbon atoms with the same number of neutrons but have different numbers of protons, they are isotopes of carbon. This is because their atomic numbers will be different, but the mass number will be the same.

Isotopes have the same atomic number and the same number of protons but a different number of neutrons and mass numbers. In general, isotopes have the same chemical properties but different physical properties. These properties include radioactivity and stability, half-life, and atomic mass. Carbon-12 and carbon-14 are examples of isotopes of carbon, with carbon-12 having six neutrons and carbon-14 having eight neutrons.

Two atoms of carbon having the same number of neutrons are called isotopes. They differ in the number of protons present in their nuclei.

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The molecular weight (W) of the polyatomic ideal gas is equal to the temperature (T) divided by the volume (V) calculated as 0.123 kJ/(K).

The molecular weight (W) of the polyatomic ideal gas can be determined using the ideal gas equation:

PV = mRT

where:

P = pressure of the gas (in this case, it is not given)

V = volume of the gas (in this case, it is not given)

m = mass of the gas (in kilograms)

R = ideal gas constant (0.123 kJ/(kg.K))

T = temperature of the gas (in Kelvin)

To calculate the molecular weight (W), we need to find the value of m. Since the pressure and volume are not provided, we can rearrange the ideal gas equation as follows:

m = PV / (RT)

Now, let's assume a hypothetical situation where we have 1 kg of the polyatomic ideal gas. In this case, the mass (m) would be equal to 1 kg.

Substituting the values into the equation:

m = (1 kg) * V / (0.123 kJ/(kg.K) * T)

Here, we can see that the units of kilograms (kg) cancel out, leaving us with:

1 = V / (0.123 kJ/(K))

To isolate V, we multiply both sides of the equation by 0.123 kJ/(K):

0.123 kJ/(K) = V

Now, we have the volume (V) in cubic meters. The molecular weight (W) can be calculated using Avogadro's law, which states that equal volumes of gases, at the same temperature and pressure, contain an equal number of molecules.

To calculate the molecular weight (W), we need to determine the number of moles (n) of the gas. The number of moles can be found using the equation:

n = PV / (RT)

However, since the pressure and volume are not provided, we cannot calculate the number of moles directly. Instead, we can make use of the molar mass (M) of the gas, which is the mass of 1 mole of the gas.

The molar mass (M) is related to the molecular weight (W) as follows:

M = W / 1000

Since we assumed a mass of 1 kg earlier, the molar mass (M) can be calculated as:

M = (1 kg) / n

Substituting the value of n from the equation above:

M = (1 kg) / (PV / (RT))

M = RT / PV

Now, substituting the value of R (0.123 kJ/(kg.K)) and rearranging the equation:

M = (0.123 kJ/(kg.K)) * T / (0.123 kJ/(K) * V)

The units of kJ cancel out, leaving us with:

M = T / V

Using the value of V we calculated earlier (0.123 kJ/(K)), we can determine the molecular weight (W) of the polyatomic ideal gas.

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The surface excess of the different concentrations of sugar solutions are 0.052, 0.124, 0.200, 0.279, and 0.361 umol/m2 for concentrations of 0.01, 0.02, 0.03, 0.04, and 0.05 M, respectively.

Given:
The concentration and the surface tension at 25 degrees Celsius of different sugar solutions.

The surface tension (γ) of water decreases when dissolved with sucrose (a common non-ionic molecular solid) as it causes an increase in the surface excess (Γ).

Surface excess of a solute in a solution is the difference in the concentration of a solute between the bulk and surface of the solution.

For sugar solution, the relationship between surface tension and surface excess is given by the Gibbs adsorption equation:

∆G = -RT ln (1 + Γ/C)

Where ∆G is the Gibbs free energy of adsorption,

R is the gas constant,

T is temperature,

C is the concentration of the solute,

and Γ is the surface excess of the solute.

Calculating the surface excess of the different concentrations of sugar solutions shown below:

Concentration Surface Tension at 25 (N/m) Surface Excess (umol/m^2)

0.01 0.841 ?

0.02 0.862 ?

0.03 0.894 ?

0.04 0.912 ?

0.05 0.955 ?

Let's calculate the surface excess for a 0.01 M sugar solution.

The molar mass of sucrose (C12H22O11) is 342.3 g/mol.0.01 M

sucrose solution contains:(0.01 mol / 1 L) x (342.3 g / 1 mol)

= 3.423 g/LConvert g/L to umol/m2 (1 L

= 10^6 umol/m2):3.423 g/L x (1 mol / 342.3 g) x (10^6 umol / 1 mol)

= 9.992 umol/m2

Use the Gibbs adsorption equation to calculate surface excess,Γ = (C/RT) * (∆G - ln (1 + Γ/C))

where R = 8.314 J/mol.

K and T = 25 + 273.15 = 298.15 K

At 0.01 M sugar solution,

∆G = 42.2 J/mol.

∆G = -RT ln (1 + Γ/C) + 0.06 Γ42.2 J/mol

= -8.314 J/mol.K x 298.15 K x ln (1 + Γ/3.423) + 0.06 ΓSolving for Γ:Γ

= 0.052 umol/m2

For 0.02 M sugar solution,∆G = 50.6 J/mol.Γ = 0.124 umol/m2

For 0.03 M sugar solution,∆G = 55.7 J/mol.Γ = 0.200 umol/m2

For 0.04 M sugar solution,∆G = 60.0 J/mol.Γ = 0.279 umol/m2

For 0.05 M sugar solution,∆G = 63.9 J/mol.Γ = 0.361 umol/m2

The calculated values of surface excess for the different concentrations of sugar solutions are as follows:

Concentration Surface Tension at 25 (N/m) Surface Excess (umol/m^2)

0.01                0.841        0.052

0.02               0.862       0.124

0.03               0.894       0.200

0.04                0.912       0.279

0.05               0.955        0.361

Therefore, the surface excess of the different concentrations of sugar solutions are 0.052, 0.124, 0.200, 0.279, and 0.361 umol/m2 for concentrations of 0.01, 0.02, 0.03, 0.04, and 0.05 M, respectively.

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In the body, neurotransmitters are chemical messengers that travel short distances (e.g., brain); whereas hormones are chemical messengers that travel long distances.

In the body, neurotransmitters are chemical messengers that travel short distances, such as within the brain, to transmit signals between nerve cells (neurons). Neurotransmitters are released from the synaptic vesicles of a neuron into the synaptic cleft, where they bind to receptors on the neighboring cell, transmitting the signal across the synapse.

Hormones, on the other hand, are chemical messengers that travel long distances throughout the body via the bloodstream. They are produced by endocrine glands and are released into the bloodstream, which carries them to target cells or organs located at a distance from the site of hormone secretion. Hormones regulate various physiological processes, including growth, metabolism, reproduction, and response to stress.

In summary, neurotransmitters act as chemical messengers for short-distance communication within the nervous system, while hormones serve as chemical messengers for long-distance communication throughout the body via the bloodstream.

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To identify the limiting reactant, we need to compare the amount of each reactant to the balanced chemical equation. The balanced equation for the reaction between nitrogen and hydrogen to produce ammonia is:

N2 + 3H2 → 2NH3

From the equation, we can see that one mole of nitrogen reacts with three moles of hydrogen to produce two moles of ammonia.

First, let's convert the mass of nitrogen to moles:

45.25 g N2 x (1 mol N2/28.02 g N2) = 1.612 mol N2

Next, let's convert the volume of hydrogen to moles using the ideal gas law:

PV = nRT

n = PV/RT

n = (52.5 L) (1 atm) / (0.0821 L·atm/mol·K) (273 K) = 2.19 mol H2

Now we can compare the number of moles of each reactant to see which is limiting:

N2 : H2 = 1.612 mol : 2.19 mol

According to the balanced equation, one mole of nitrogen reacts with three moles of hydrogen. So we need 4.836 moles of hydrogen to completely react with 1.612 moles of nitrogen. However, we only have 2.19 moles of hydrogen, which means it is the limiting reactant.

Therefore, the amount of ammonia that can be produced is limited by the amount of hydrogen available.

The balanced equation shows that 3 moles of hydrogen produces 2 moles of ammonia. So, with 2.19 moles of hydrogen, we can produce:

2.19 mol H2 x (2 mol NH3/3 mol H2) = 1.46 mol NH3

Now, let's convert the moles of ammonia to liters using the ideal gas law:

PV = nRT

V = nRT/P

V = (1.46 mol) (0.0821 L·atm/mol·K) (273 K) / (1 atm) = 31.2 L

Therefore, 31.2 liters of ammonia gas can be produced from the given amount of nitrogen To identify the limiting reactant, we need to compare the amount of each reactant to the balanced chemical equation. The balanced equation for the reaction between nitrogen and hydrogen to produce ammonia is:

N2 + 3H2 → 2NH3

From the equation, we can see that one mole of nitrogen reacts with three moles of hydrogen to produce two moles of ammonia.

First, let's convert the mass of nitrogen to moles:

45.25 g N2 x (1 mol N2/28.02 g N2) = 1.612 mol N2

Next, let's convert the volume of hydrogen to moles using the ideal gas law:

PV = nRT

n = PV/RT

n = (52.5 L) (1 atm) / (0.0821 L·atm/mol·K) (273 K) = 2.19 mol H2

Now we can compare the number of moles of each reactant to see which is limiting:

N2 : H2 = 1.612 mol : 2.19 mol

According to the balanced equation, one mole of nitrogen reacts with three moles of hydrogen. So we need 4.836 moles of hydrogen to completely react with 1.612 moles of nitrogen. However, we only have 2.19 moles of hydrogen, which means it is the limiting reactant.

Therefore, the amount of ammonia that can be produced is limited by the amount of hydrogen available.

The balanced equation shows that 3 moles of hydrogen produces 2 moles of ammonia. So, with 2.19 moles of hydrogen, we can produce:

2.19 mol H2 x (2 mol NH3/3 mol H2) = 1.46 mol NH3

Now, let's convert the moles of ammonia to liters using the ideal gas law:

PV = nRT

V = nRT/P

V = (1.46 mol) (0.0821 L·atm/mol·K) (273 K) / (1 atm) = 31.2 L

Therefore, 31.2 liters of ammonia gas can be produced from the given amount of nitrogen and hydrogen.

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Answer:

Study Island:

The answer is...

C.  The test variable (independent variable) and outcome variable (dependent variable) have no affect on each other.

Explanation:

The test variable (independent variable) and the outcome variable (dependent variable) have no effect on each other. Hence, option C is correct.

The independent variable can be altered, manipulated and changed in an experimental study.

Researchers often measure independent and dependent variables in studies to test cause-and-effect relationships.

The independent variable is the reason or cause. Its value is independent of other variables.

The dependent variable is the outcome whose values depend on changes in the independent variable.

Hence, option C is correct.

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198 ml To create 4% NaOH, you will need 7.92 grammes of sodium hydroxide, or (4 x 198)/100. So, 7.92 grammes of sodium hydroxide are dissolved in 198 ml of water.

The molarity of a solution is decreased by dilution. An aqueous solution's volume grows with the addition of more water, while the solute's moles remain constant. As a result, the solution's concentration and molarity are reduced.

Dilution happens as the solution's volume increases. As just a result, conductivity decreases and ions per millilitre increase. The molar conductivity is calculated using one mole of ions. The molar conductivity of the solution rises as a result of increased ion separation and mobility.

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Expressing the answer in exponential form we get 3⁴.

To simplify the expression (3⁷/(3³), we can apply the properties of exponents. When dividing two exponential expressions with the same base, we subtract the exponents.

In this case, we have 3⁷ divided by 3³, which can be simplified as:

3⁽⁷⁻³⁾

3⁴

Therefore, the simplified expression is 3⁴.

To understand why we subtract the exponents when dividing, we can break down the steps.

The expression 3⁷ represents 3 multiplied by itself seven times:

3 × 3 × 3 × 3 × 3 × 3 × 3.

The expression 3³ represents 3 multiplied by itself three times:

3 × 3 × 3.

When dividing these two expressions, we can cancel out common factors by subtracting the exponents:

(3 × 3 × 3 × 3 × 3 × 3 × 3) / (3 × 3 × 3)

This simplifies to:

3 × 3 × 3 × 3

Which is equivalent to 3⁴.

Thus, the answer in exponential form is 3⁴

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Explanation:

so why some metals react with cold water and not hot water because in the reactivity series the some of which are more reactive like potassium and sodium which can react with cold water and which react with hot water it's because those need more activation energy compared to the others so in cold water will provide less activation energy compared to hot water has thermal energy that's what I can say is that's why some metals react with hot water and cold water hot water has more activation energy, activation energy is the energy needed to initiate a chemical reaction and the diagram I would say you could use the apparatus like measuring cylinder Beaker and water so you take magnesium ribbon you first insert it in cold water will see there's no reaction but when you insert in hot water they will be formation of magnesium hydroxide and hydrogen gas.

Answer:

C, organelles can all be different in an animal

Explanation:

Organelles DO perform a certain function for a cell,

Organelles ARE membrane enclosed structures,

and Organelles ARE separated from other parts of the cell

Comparing the energy of an electrostatic interaction between two ions bearing single opposite charges separated by 3 angstroms, the energy level of these ions in water is lower than that in hexane because the dielectric constant of water is higher than the dielectric constant of nonpolar solvent.

The dielectric constant of water is 80 whereas the dielectric constant of hexane is 2. the dielectric constant is a measure of the solvent's ability to decrease the Coulombic forces between ions or polar molecules. When two oppositely charged ions are placed in a solvent, their electrostatic attraction for one another may be reduced due to the presence of other ions and solvent molecules that mediate the interaction. The magnitude of this decrease is dependent on the dielectric constant of the solvent. A solvent with a high dielectric constant will more effectively screen electrostatic interactions than a solvent with a low dielectric constant. Water has a high dielectric constant due to its polar nature, whereas hexane has a low dielectric constant due to its nonpolar nature.

The energy level of these ions in water is lower than that in hexane because the dielectric constant of water is higher than the dielectric constant of nonpolar solvent.

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Answer:

Atoms are at their most stable when their outermost energy level is either empty of electrons or filled with electrons.

Answer:

Iodine

Explanation:

Iodine is located in the 5th period, meaning that it will have 5 energy levels.

Additionally, Iodine has an atomic mass of about 127 atomic mass units, and since it has 53 protons, it will have 74 neutrons.

Let me know if this helps!

Explanation:

e is right now answer for teaching us

Answer:

Explanation:

Answer:

In a periodic table the average atomic mass of magnesium is given as 24.312 u.

The equilibrium equation for the salt AB can be represented as;AB ⇌ a^+ + b^-Ksp= [a^+] [b^-]The solubility product for the salt AB.

Ksp is given by the product of the molar concentration of the two ions raised to their respective powers. For the given equilibrium, the concentration of b^- is 8.3 × 10^-7 M, then the solubility product can be calculated by substituting the concentration of b^- into the equilibrium equation.Ksp = [a^+] [8.3 × 10^-7].Hence, the solubility product for the salt AB can be determined by multiplying the concentration of the ions raised to their respective powers. In this case, the concentration of b^- is 8.3 × 10^-7 M, then the solubility product can be calculated by substituting the concentration of b^- into the equilibrium equation.

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In an octahedral transition metal complex, Ao can be measured as the energy difference between two sets of d-orbitals : D) (dxy, dx2-y2) & (dz?, dxz, dyz).

Option A includes the sets (dxy, dxz, dyz) and (dz2, dx2-y2), which are relevant when the ligands are all in the xy-plane. Option B includes the sets (dxy, dxz) and (dyz, dz2, dx2-y2), which are relevant when the ligands are split into two groups, one in the xy-plane and the other along the z-axis. Option C includes the sets (dxy, dxz, dx2-y) and (dyz, dz?), which are relevant when the ligands are split into two groups, one in the xy-plane and the other along the z-axis, but with some degree of degeneracy. Option D includes the sets (dxy, dx2-y2) and (dz?, dxz, dyz), which are relevant when the ligands are all along the z-axis.

The energy difference between these sets of d-orbitals is denoted as Ao, and it represents the amount of energy required to transition an electron from the lower energy set to the higher energy set. This energy difference is related to the colors observed in transition metal complexes, with higher Ao values corresponding to higher energy transitions and shorter wavelength colors (e.g. blue and violet), and lower Ao values corresponding to lower energy transitions and longer wavelength colors (e.g. orange and red).

In conclusion, the answer to the question is D) (dxy, dx2-y2) & (dz?, dxz, dyz), as these are the two sets of d-orbitals involved in measuring the energy difference Ao in an octahedral transition metal complex with ligands along the z-axis.

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Answer:

b because the detective ate coffee all day

The final temperature of both substances at thermal equilibrium is 51.96°C.

Solution:

31.91 T =10374.27

T= 325.11 K or T= 51.96 °c

Final equilibrium Temperature (T) = 51.96°C.

Two systems are said to be in thermal equilibrium when they are in contact with each other and there is no energy flow between them. Simply put, thermal equilibrium means that two systems are at the same temperature. The zero law of thermodynamics states that if two systems are in thermodynamic equilibrium with his third system, then the original He said that the two systems are in thermal equilibrium with each other.

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