The isotope Yittrium-90 is used in nuclear medicine to treat cancer. It undergoes radioactive decay through beta emission.
a) Write a balanced nuclear reaction for the radioactive decay of Yittrium-90.
b) A patient was injected with a 2.5 mg sample of Yittrium-90. The half-life of Yittrium-90 decay by beta emission is 64 hrs. What is the activity at the start of the treatment?
c) For the treatment to be effective the activity of the radioactive isotope must be at least 50 Ci. Will the treatment dosage be effective for 1 week?

Answer:

7. Ionization energy

8. Lattice energy

9. Free energy

10. Activation energy

Explanation:

I. Ionization energy: The energy required to convert a ground-state atom in the gas phase to a gaseous positive ion. Thus, it is the minimum energy required to remove or detach an electron from a neutral atom in a gaseous state. Generally, atoms with relatively large atomic radii tend to have a low ionization energy.

II. Lattice energy: The energy change that occurs in the conversion of an ionic solid to widely separated gaseous ions. This ultimately implies that, it is the energy generated during the conversion of an ionic solid into gaseous ions and as such is a measure of the cohesive force binding the ions of an ionic compound using the Born-Haber cycle.

III. Free energy: the energy in a chemical or physical change that is available to do useful work. Thus, it is a thermodynamic quantity that measures the maximum capacity of a system to do work at constant temperature and pressure.

IV. Activation energy: The energy required to form the transition state in a chemical reaction. When the activation energy of a reaction is low, the rate of the reaction would be faster. Therefore, an enzyme speeds or catalyzes the rate of a reaction by lowering its activation energy.

Answer:

c

Explanation:

The rate of formation of SO₃ is 4.84 × 10⁻³ m/s. The correct option is d. 4.84 × 10⁻³ M/s.

To determine the rate of formation of SO₃, we need to consider the stoichiometry of the balanced equation. The coefficient of SO₃ is 2, which means that for every 1 mole of O₂ reacted, 2 moles of SO₃ are formed.

Given that the rate of O₂ loss is 2.42 × 10⁻³ m/s, we can use the stoichiometry to find the rate of formation of SO₃.

Rate of formation of SO₃ = (2 moles SO₃ / 1 mole O₂) × (2.42 × 10⁻³ m/s)

Rate of formation of SO₃ = 4.84 × 10⁻³ m/s

Therefore, the rate of formation of SO₃ is 4.84 × 10⁻³ m/s. The correct option is d. 4.84 × 10⁻³ M/s.

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Answer:

31.3 mL

Explanation:

We'll begin by writing the balanced equation for the reaction. This is illustrated below:

2HCl + Ba(OH)₂ —> BaCl₂ + 2H₂O

From the balanced equation above,

The mole ratio of the acid, HCl (nₐ) = 2

The mole ratio of the base, Ba(OH)₂ (n₆) = 1

Finally, we shall determine the volume of the acid need for the reaction as follow:

Molarity of acid, HCl (Mₐ) = 0.062 M

Mole ratio of the acid, HCl (nₐ) = 2

Volume of base, Ba(OH)₂ (V₆) = 19.4 mL

Molarity of base, Ba(OH)₂ (M₆) = 0.050 M

Mole ratio of the base, Ba(OH)₂ (n₆) = 1

Volume of acid, HCl (Vₐ) =?

MₐVₐ / M₆V₆ = nₐ / n₆

0.062 × Vₐ / 0.050 × 19.4 = 2/1

0.062 × Vₐ / 0.97 = 2

Cross multiply

0.062 × Vₐ = 0.97 × 2

0.062 × Vₐ = 1.94

Divide both side by 0.062

Vₐ = 1.94 / 0.062

Vₐ = 31.3 mL

Thus, the volume of the acid needed is 31.3 mL

A buffer is primarily used to limit the pH change in a solution. Option A is correct.

A buffer is the solution which contains the weak acid and its conjugate base or weak base and its conjugate acid. It is designed to resist changes in pH when small amounts of acid or base are added to it.

When an acid or base is added to a buffer solution, the buffer components react with the added ions to minimize the impact on the solution's pH. If an acid is added, the buffer will react with the acid by accepting the H⁺ ions. If a base is added, the buffer will react with the base by donating H⁺ ions. In both cases, the buffer helps maintain the pH at a relatively stable level.

To prevent an acid from dissociating, is not accurate. A buffer does not prevent an acid from dissociating. In fact, the acid in a buffer solution is necessary to provide the conjugate base and maintain the buffer's pH buffering capacity.

To neutralize the pH of a solution, is also not accurate. A buffer does not neutralize the pH of a solution to a particular value. Instead, it resists significant changes in pH when small amounts of acid or base are added.

To prevent a salt from dissolving, is unrelated to the purpose of a buffer. A buffer is not used to prevent the dissolution of salts.

Hence, A. is the correct option.

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Option a, 1000 L of liquid water, is likely to have the highest heat capacity among the given options.

The heat capacity of a substance refers to the amount of heat energy required to raise the temperature of that substance by a certain amount. In general, substances with higher molar masses and larger numbers of atoms or molecules tend to have higher heat capacities.

Given the options provided:

a. 1000 L of liquid water has a higher heat capacity compared to the other options because water has a relatively high molar mass and specific heat capacity.

b. 10 g of sand generally has a lower heat capacity compared to water since sand has a lower molar mass and specific heat capacity.

c. 1 g of iron has a moderate heat capacity. While iron has a higher molar mass compared to sand, it typically has a lower specific heat capacity than water.

d. 5 g of glass generally has a lower heat capacity compared to water, as glass has a lower molar mass and specific heat capacity.

Therefore, option a, 1000 L of liquid water, is likely to have the highest heat capacity among the given options.

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The half-life of the radioisotope is approximately 14.72 hours, which is closest to option d) 1.44 hr (1 hour and 26.4 minutes).

Radioisotopes are radioactive isotopes of elements that are used in a variety of applications, including medical imaging and cancer treatment. They are also used in geology and archaeology to determine the age of rocks and artifacts. The activity of a radioisotope is the rate at which it decays, measured in counts per minute (CPM). The half-life of a radioisotope is the amount of time it takes for half of the atoms to decay.

Given that the activity of a radioisotope is 3000 counts per minute at one time and 2736 counts per minute 48 hours later, we can use the formula A = A₀ (1/2)^(t/T) to find the half-life of the radioisotope.

Where A is the activity after time t, A₀ is the initial activity, T is the half-life, and t is the time elapsed.

Substituting the values given in the problem, we get:

2736 = 3000 (1/2)^(48/T)

Dividing both sides by 3000, we get:

0.912 = (1/2)^(48/T)

Taking the natural logarithm of both sides, we get:

ln 0.912 = ln (1/2)^(48/T)

Using the rule that ln (a^b) = b ln a, we get:

ln 0.912 = (48/T) ln (1/2)

Dividing both sides by ln (1/2), we get:

ln 0.912 / ln (1/2) = 48/T

Using a calculator to evaluate the left-hand side, we get:

3.26 = 48/T

Multiplying both sides by T, we get:

3.26T = 48

Dividing both sides by 3.26, we get:

T ≈ 14.72 hours

Therefore, the half-life of the radioisotope is approximately 14.72 hours, which is closest to option d) 1.44 hr (1 hour and 26.4 minutes).

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Answer:

Report of the climate change can help the people. As when people wants to go for  picnics or somewhere else. They did not have any idea that what will be the climate when they go. Report of climate change help him to choose the right time for going on picnics or  somewhere else.

Answer:

The report mentioned ways that people’s lives may change because of climate change, such as rising sea levels, reduced crop efficiency, and heat waves. This information may encourage the public to change the way they use energy, for example how they heat their homes or power their cars.

Explanation:

Answer:

q = mC∆T

q = heat = ?

m = mass = 6.30 g

C = specific heat = 0.385 J/g/deg

∆T = change in temperature = 32-20 = 12º

q = ((6.30 g)(0.385 J/g/deg)(12 deg) = 29.1 J (to 3 significant figures)

Explanation:

The Required Correct Answer for the rate of appearance of N2 is 1.4 g/s.

Explanation : Given reaction is2NH3(g) → N2(g) + 3H2(g)The stoichiometric coefficients of NH3 and N2 in the balanced chemical equation are 2 and 1 respectively, which indicates that one mole of N2 is produced for every 2 moles of NH3 consumed.The rate of disappearance of NH3 is 1.7 g/s.

Number of moles of NH3 disappearing per second can be determined by the following formula:n = m/MwWhere,n = number of moles of NH3 disappearing per secondm = mass of NH3 disappearing per secondMw = molecular weight of NH3.The molecular weight of NH3 is 17 g/mol.

So,m/Mw = 1.7/17= 0.1 mole/sNow we know that 2 moles of NH3 produce 1 mole of N2. Hence, 0.1 mole/s of NH3 will produce (1/2) × 0.1 = 0.05 mole/s of N2The mass of N2 produced can be calculated by using the formula:m = n × MwThe molecular weight of N2 is 28 g/mol.So, m = 0.05 × 28= 1.4 g/s

Therefore, the rate of appearance of N2 is 1.4 g/s.

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1) State the equation that represents the chemical reaction

P2O5 + 3H2O → 2H3PO4

2) State the molar ratios: 1 mol P2O5 : 3 mol H2O : 2 mol H3PO4

3) Use the proportions 3molH2O / 2 mol H3PO4

0.729 mol H3PO4 * [ 3 mol H2O / 2 mol H3PO4] = 1.094 mol H2O

Answer: 1.094 mol of water

Answer: The answer that i got for this is 1.09 give the other kid the brainliest.

Explanation:

If you take an antacid tablet, the ph in your stomach will increase. this means your stomach juice becomes more acidic - False

The stomach's pH will rise if a person takes an antacid pill. Antacids neutralise excess stomach acid to treat conditions like gastroesophageal reflux disease, heartburn, and acid indigestion. They usually consist of elements such as calcium carbonate, magnesium or aluminium hydroxide; when coupled with stomach acid, these elements react to form salts and water.

Antacids reduce the acidity of the stomach contents by raising the pH level and neutralising the stomach's acid. This can aid in reducing the symptoms brought on by excessive acid production. Therefore, it is untrue that taking an antacid increases the acidity of the stomach liquid.

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Answer:

For A: The molarity is the solution 9.706 M

For B: The molarity of the solution is 10.91 M.

For C: The molarity of the solution is 1.78 M.

Explanation:

Molarity is defined as the amount of solute expressed in the number of moles present per liter of solution. The units of molarity are mol/L.

The formula used to calculate molarity:

[tex]\text{Molarity of solution}=\frac{\text{Number of moles of solute}}{\text{Volume of solution (L)}}[/tex]                 ......(1)

For A:

Number of moles = 3.30 moles

Volume of solution = 0.340 L

Plugging values in equation 1:

[tex]\text{Molarity of solution}=\frac{3.30 mol}{0.340 L}=9.706 mol/L[/tex]

For B:

Number of moles = 6.00 moles

Volume of solution = 550 mL = 0.550 L        (Conversion factor: 1 L = 1000 mL)

Plugging values in equation 1:

[tex]\text{Molarity of solution}=\frac{6.00 mol}{0.550 L}=10.91 mol/L[/tex]

For C:

Number of moles = 0.0160 moles

Volume of solution = 9.00 mL = 0.009 L

Plugging values in equation 1:

[tex]\text{Molarity of solution}=\frac{0.0160 mol}{0.009 L}=1.78 mol/L[/tex]

Answer:

I'll do the first one for you. The reason why I'm not going to do the rest is because this is pretty simple stuff. I'll explain how I got the answer, please read it ^^ the rest of the problems should be a breeze.

1. 5.454285714285714 liters, or approx. 5.45 liters

Explanation:

P1V2 = P2V2

P1 refers to the original pressure. V1 refers to the original volume, or the amount of space the gas takes up.

P2 and V2 refer to the final pressure or volume, accordingly.

You insert the values into the equation, like so:

(8.3)(46) = (70)(x)

Now, multiply.

381.8 = 70x

Use inverse operations to find the value of x. Divide 381.8 by 70 to isolate x.

381.8/70 = x

5.454285714285714 = x

The volume of the gas when the pressure is increased to 70.0 mm Hg is approximately 5.45 liters. Don't forget about the units at the end, when you write your final answer.

Important! When pressure increases, volume decreases, and vice versa. Volume and pressure for gases are inversely proportional. So even though the pressure increased, that doesn't mean the volume increases, too.

You can check your answers easily!

Just multiply your final answer by its corresponding pressure or volume and compare it to the other. I hope that made sense. Like so:

5.454285714285714 x 70 = 381.8

8.3 x 46 = 381.8

That makes P1V2 DOES equal P2V2, and your answer is correct.

I hope this helped in time for you to submit it before the deadline! Good luck.

Tips!

For #2: I'm pretty sure the mentioning of the temperature (25.0 °C) doesn't matter. You can ignore it, it won't affect your calculations.

For #4: the standard pressure in mm Hg (millimeters of mercury) is 760 mm Hg. That's your P2.

Answer:

E

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E

E

E

E

E

E

E

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BRAINLIEST PLEASE

Answer

Plants can respond to the change of season by losing their leaves, flowering, or breaking dormancy. Plants go through seasonal changes after detecting differences in day length.

Explanation:

The noble gas expected to show the largest deviations from the ideal gas behavior is Xenon (Xe).The molar volume of a gas at STP is 22.4 L. This is because 1 mole of gas occupies 22.4 L of volume at 0°C and 1 atm pressure

The ideal gas behavior is only possible at low pressures and high temperatures. A gas can be assumed to be ideal if its atoms or molecules are far apart and there is no interaction between them. Since noble gases are monatomic gases and their atoms are quite far apart, they are expected to behave like ideal gases.However, xenon is the largest of all noble gases, and its atoms have large sizes and masses. As a result, they experience stronger attractive forces between atoms than the other noble gases, leading to deviations from ideal gas behavior.The molar volume of a gas at STP is 22.4 L. This is because 1 mole of gas occupies 22.4 L of volume at 0°C and 1 atm pressure. Hence, the correct answer is option D) 22.4.

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Answer:

They study different way people have died or could die to better aid investigators.

Explanation:

Answer:

Corrosion is the process of deterioration of materials as a result of chemical, electrochemical or other reactions. Rusting is a part of corrosion and is a chemical process which results in the formation of red or orange coating on the surface of metals. ... Rust or rusting can affect only iron and its alloys.

Explanation:

Based on the observations described, it is likely that the white solid is a true hydrate.

Water droplets on the side of the test tube: When heating a hydrate, the water molecules trapped within the crystal lattice are released as vapor. The presence of water droplets on the side of the test tube indicates that water was indeed released during the heating process.

Brownish residue: The brownish residue obtained after heating the solid suggests that the white solid might contain a transition metal ion. Transition metal ions can form complex compounds that exhibit different colors, including brown.

Dissolving in water: The brownish residue dissolves in water, indicating that it is soluble in the solvent.

Dark reddish-brown solution: The solution obtained after dissolving the brownish residue is described as dark reddish-brown. This color could be attributed to the formation of a complex compound between the transition metal ion in the residue and the water or other substances present in the solution.

Based on the observations of water droplets upon heating, the brownish residue that dissolves in water, and the resulting dark reddish-brown solution, it is likely that the white solid is a true hydrate.

The presence of water droplets and the dissolution of the residue suggest that water was released from the solid during heating, indicating the presence of water molecules within the crystal lattice.

The color change to brownish and the subsequent dark reddish-brown solution point towards the involvement of a transition metal ion, possibly forming a complex compound.

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A phase diagram is a graphical representation or map that shows the different phases (solid, liquid, and gas) of a substance as a function of pressure and temperature. It provides valuable information about the conditions under which a substance exists in each phase or undergoes phase transitions.

In a phase diagram, pressure is typically represented on the y-axis, and temperature is represented on the x-axis. The diagram is divided into regions corresponding to different phases, and boundaries or lines separating these regions represent phase transitions.

The phase diagram allows us to determine the conditions at which a substance can exist as a solid, liquid, or gas, and it provides insights into the effects of temperature and pressure on the phase behavior of the substance.

It helps in understanding processes such as melting, boiling, and sublimation and provides a useful tool in various fields including chemistry, physics, and materials science.

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Answer:

Molecular mass is a number equal to the sum of the atomic masses of the atoms in a molecule.

Explanation:

The molecular mass gives the mass of a molecule relative to that of the 12 C atom, which is taken to have a mass of 12. Hence why Molecular mass is a number equal to the sum of the atomic masses of the atoms in a molecule.

Water molecules that surround the metal ions act as weak Brønsted-Lowry acids and donate protons to the solution, increasing its acidity.

Hydrated transition metal ions typically produce solutions that are acidic. Transition metal ions are elements from the transition series that are capable of forming coordination complexes that have characteristic colors, and they exhibit a wide range of oxidation states and show various magnetic properties.In addition, when transition metals react with water, they create hydrated metal ions, which produce acidic solutions. This is because water molecules that surround the metal ions act as weak Brønsted-Lowry acids and donate protons to the solution, increasing its acidity.Therefore, the correct answer is (a) acidic.

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The product of the reaction between [tex]CH_{3}[/tex]-CH=[tex]CH_{2}[/tex] and HBr is 2-bromo-3-methylbutane.

The reaction proceeds through the addition of a proton from HBr to the double bond, followed by the addition of a bromide ion.

The addition of the proton is stereospecific, and the bromide ion will add to the carbon atom that is least substituted by hydrogen. In this case, the carbon atom that is least substituted by hydrogen is the carbon atom that is attached to two hydrogen atoms.

Therefore, the bromide ion will add to the carbon atom that is attached to the double bond and the methyl group. The product of the reaction is 2-bromo-3-methylbutane.

here is the predominant product of the reaction of [tex]CH_{3}CHCH=CH-CH_{3}[/tex] with HBr:

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The complete question is:

Draw the predominant product(s) of the following reactions including stereochemistry when appropriate. CH CH CH -CEC-H HBr Consider EIZ stercochemistry of alkenes. Do not show stereochemistry in other cases If no reaction occurs_ raw the organic starting material. Draw one stnicture per sketcher Add additional sketchers using the drop down menu in the bottom right corner Separate multiple products using the sign from the drop-down menu: ChemDoodle Submit Answver Retry Entire Group more cirovp attempts remaining

Answer:

D

Explanation:

It states that D has oxygen, and is closer to the Sun.

Hope this helped, and please mark as Brianliest <3

Answer:

I am pretty sure it is B

Explanation:

The others would either burn u like a crispy chicken nugget or freeze you like a popsicle

Answer:

m = 204.16 grams

Explanation:

Given that,

No. of moles, n = 3.49

Molar mass of NaCl, M = 58.5 g/mol

We need to find the mass of 3.49 moles NaCl​. We know that,

[tex]n=\dfrac{m}{M}\\\\m=n\times M\\\\m=3.49 \times 58.5\\\\m=204.16\ g[/tex]

So, there are 204.16 grams in 3.49 moles NaCl​.