Question 1

Barium is a nonessential element in the human body, but some organisms build exoskeletons using barium sulfate, which has a K_sp of 1.1 $\times$ 10^-10 at 25S1U1P1$\circ$S1S1P0C. What is the mass of barium in 1.0 L of a saturated solution of barium sulfate at 25S1U1P1$\circ$S1S1P0C?

Accepted Answer

The solubility product constant (Ksp) for barium sulfate (BaSO4) at 25°C is 1.1 × 10^-10. To find the mass of barium in a saturated solution, we first calculate the molar solubility of BaSO4. Since BaSO4 dissociates into Ba^2+ and SO4^2- in a 1:1 ratio, the concentration of Ba^2+ in a saturated solution is equal to the molar solubility of BaSO4. $$ K_{sp} = [Ba^{2+}][SO_4^{2-}] = (s)(s) = s^2 $$Solving for s (molar solubility):$$ s^2 = 1.1 \times 10^{-10} $$$$ s = \sqrt{1.1 \times 10^{-10}} $$$$ s \approx 1.05 \times 10^{-5} \, M $$To find the mass of barium in 1.0 L of this solution, we convert the molarity of Ba^2+ to moles and then to grams:$$ 1.05 \times 10^{-5} \, mol/L \times 1.0 \, L = 1.05 \times 10^{-5} \, mol $$$$ 1.05 \times 10^{-5} \, mol \times 137.33 \, g/mol \approx 1.44 \times 10^{-3} \, g $$$$ 1.44 \times 10^{-3} \, g = 1.4 \, mg $$Therefore, the mass of barium in 1.0 L of a saturated solution of barium sulfate at 25°C is approximately 1.4 mg.

Question 2

Pacemakers implanted in the chests of patients with certain heart conditions are powered by a lithium/iodine PVP battery, where PVP represents polyvinylpyridine. The cell reaction and standard cell potential are given below. The standard reduction potential for Li/LiS1U1P1+S1S1P0 is -3.05 V. What is the standard reduction potential for the iodine PVP half-reaction?  $~~~~~~~~$3.59 V

Accepted Answer

The answer of Pacemakers implanted in the chests of patients...

Question 3

The cation BiO⁺ is found in some over-the-counter antacids. Draw the Lewis structure of this cation that satisfies the octet rule for both atoms. Based on this Lewis structure, this cation has ________ of nonbonding electrons.

Accepted Answer

The answer of The cation BiO⁺ is found in some...

Question 4

Rhenium-186 has medical applications. It decays by $\beta$ emission. What isotope is formed from this decay?

Accepted Answer

Rhenium-186 decays by beta-minus (F1) emission, which converts a neutron into a proton, and emits an electron and an antineutrino. The resulting isotope will have an atomic number that is one greater than rhenium (75) but the same mass number (186), as the electron has very little mass. This corresponds to choice B, which is osmium-186 (76 protons, 186 neutrons).

Question 5

Thallium-201 is used in cardiac imaging. It decays by electron capture. What isotope is produced when thallium-201 captures an electron?

Accepted Answer

When thallium-201 undergoes electron capture, it transforms into mercury-201. This process involves the capture of an inner orbital electron by the nucleus, which decreases the atomic number by one, changing thallium (atomic number 81) to mercury (atomic number 80).

Question 6

Hearing aid batteries utilize a zinc/air electrochemical cell. The reduction half-reactions and standard reduction potentials for this cell are given below. What species are oxidized and reduced in the cell reaction?  $~~~~~~~~$-1.249 V $~~~~~~~~$+0.401 V

Accepted Answer

The answer of Hearing aid batteries utilize a zinc/air electrochemical...

Question 7

Radioactive tritium, ³H, is used as a tracer in many biological experiments. It decays by $\beta$ emission. What is the product of this decay?

Accepted Answer

Tritium (³H) undergoes beta decay, where a neutron is converted into a proton, resulting in the formation of helium-3 (³He).

Question 8

Which element may contribute to sudden infant death syndrome (SIDS), as it is used as a fire retardant in mattresses?

Accepted Answer

Antimony is often used as a fire retardant in mattresses and has been identified as a potential contributor to SIDS. Studies have shown a correlation between the presence of antimony in crib mattresses and an increased risk of SIDS.

Question 9

Lithium is used in the treatment of which disease?

Accepted Answer

Lithium is primarily used in the treatment of bipolar disorder, a mental health condition characterized by mood swings between mania and depression. It is considered a mood stabilizer and can help reduce the frequency and severity of manic or depressive episodes in patients with bipolar disorder.

Question 10

Pacemakers implanted in the chests of patients with certain heart conditions are powered by a lithium/iodine PVP battery, where PVP represents polyvinylpyridine. The cell reaction and standard cell potential are given below. The standard reduction potential for Li/LiS1U1P1+S1S1P0 is -3.05 V. What species is oxidized in this reaction? 
 $~~~~~~~~$3.59 V

Accepted Answer

In the cell reaction, Li is being reduced (since it has the higher reduction potential) while I- is being oxidized. Therefore, the species being oxidized is I-.

Question 11

A patient is injected with a 5.0 $\mu$M solution of gallium citrate containing radioactive gallium-68 for a PET study. The half-life of gallium-68 is 9.4 hr. How long does it take for the activity of this isotope to drop to 1% of its initial value?

Accepted Answer

The answer of A patient is injected with a 5.0...

Question 12

The release of radioactive cesium-137 into the environment by the nuclear accident at Chernobyl produced a health hazard because cesium ions can substitute for ________ in plants, making them unsafe for human consumption.

Accepted Answer

The answer of The release of radioactive cesium-137 into the...

Question 13

The isotope ¹⁸F is used in a range of radio imaging applications. It has a first-order rate constant, k, of 6.30 $\times$ 10^-3 min^-1. What is the half-life for ¹⁸F?

Accepted Answer

The answer of The isotope ¹⁸F is used in a...

Question 14

Hearing aid batteries utilize a zinc/air electrochemical cell. The reduction half-reactions and standard reduction potentials for this cell are given below. Write the balanced reaction equation for the cell and report the sum of the stoichiometric coefficients. 
 $~~~~~~~~$-1.249 V  $~~~~~~~~$+0.401 V

Accepted Answer

The answer of Hearing aid batteries utilize a zinc/air electrochemical...

Question 15

The isotope ²⁰¹Th is used in the diagnosis of heart disease. It has a first-order rate constant, k, of 9.49 $\times$ 10^-3 h^-1. What is the half-life for ²⁰¹Th?

Accepted Answer

The half-life (t1/2) of a first-order reaction is given by the formula t1/2 = 0.693/k. Given k = 9.49 × 10^-3 hr^-1, substituting into the formula gives a half-life of approximately 73 hours.

Question 16

A radioactive isotope that emits the shortest range particles and therefore would be a good choice for implantation therapy most likely decays via ________

Accepted Answer

Alpha particles have the shortest range because they are the heaviest and most charged among the options, causing them to lose energy quickly when passing through matter. This makes them suitable for implantation therapy, where minimizing damage to surrounding tissues is crucial.

Question 17

The essential elements found in the human body are classified as major, trace, and ultratrace based on their concentration levels. What are the concentration ranges that define each of these classifications?

Accepted Answer

The answer of The essential elements found in the human...

Question 18

Hearing aid batteries utilize a zinc/air electrochemical cell. The reduction half-reactions and standard reduction potentials for this cell are given below. What is the standard cell potential of a zinc/air cell?  $~~~~~~~~$-1.249 V  $~~~~~~~~$+0.401 V

Accepted Answer

The answer of Hearing aid batteries utilize a zinc/air electrochemical...

Question 19

A patient is injected with a 5.0 $\mu$M solution of gallium citrate containing radioactive gallium-68 for a PET study. The half-life of gallium-68 is 9.4 hr. How long does it take for the activity of this isotope to drop to 1% of its initial value?

Accepted Answer

The answer of A patient is injected with a 5.0...

Question 20

Calcium is a major essential element in the human body. What is the dominant role played by calcium?

Accepted Answer

The answer of Calcium is a major essential element in...

Quiz 21: The Main Group Elements: Life and the Periodic Table

Barium is a nonessential element in the human body, but some organisms build exoskeletons using barium sulfate, which has a K_sp of 1.1 $\times$ 10^-10 at 25^$\circ$C. What is the mass of barium in 1.0 L of a saturated solution of barium sulfate at 25^$\circ$C?

The cation BiO⁺ is found in some over-the-counter antacids. Draw the Lewis structure of this cation that satisfies the octet rule for both atoms. Based on this Lewis structure, this cation has ________ of nonbonding electrons.

Rhenium-186 has medical applications. It decays by $\beta$ emission. What isotope is formed from this decay?

Thallium-201 is used in cardiac imaging. It decays by electron capture. What isotope is produced when thallium-201 captures an electron?

Hearing aid batteries utilize a zinc/air electrochemical cell. The reduction half-reactions and standard reduction potentials for this cell are given below. What species are oxidized and reduced in the cell reaction? $$ -1.249 V $$ +0.401 V

Radioactive tritium, ³H, is used as a tracer in many biological experiments. It decays by $\beta$ emission. What is the product of this decay?

Which element may contribute to sudden infant death syndrome (SIDS) , as it is used as a fire retardant in mattresses?

Lithium is used in the treatment of which disease?

A patient is injected with a 5.0 $\mu$ M solution of gallium citrate containing radioactive gallium-68 for a PET study. The half-life of gallium-68 is 9.4 hr. How long does it take for the activity of this isotope to drop to 1% of its initial value?

The release of radioactive cesium-137 into the environment by the nuclear accident at Chernobyl produced a health hazard because cesium ions can substitute for ________ in plants, making them unsafe for human consumption.

The isotope ¹⁸F is used in a range of radio imaging applications. It has a first-order rate constant, k, of 6.30 $\times$ 10^-3 min^-1. What is the half-life for ¹⁸F?

Hearing aid batteries utilize a zinc/air electrochemical cell. The reduction half-reactions and standard reduction potentials for this cell are given below. Write the balanced reaction equation for the cell and report the sum of the stoichiometric coefficients. $$ -1.249 V $$ +0.401 V

The isotope ²⁰¹Th is used in the diagnosis of heart disease. It has a first-order rate constant, k, of 9.49 $\times$ 10^-3 h^-1. What is the half-life for ²⁰¹Th?

A radioactive isotope that emits the shortest range particles and therefore would be a good choice for implantation therapy most likely decays via ________

The essential elements found in the human body are classified as major, trace, and ultratrace based on their concentration levels. What are the concentration ranges that define each of these classifications?

Hearing aid batteries utilize a zinc/air electrochemical cell. The reduction half-reactions and standard reduction potentials for this cell are given below. What is the standard cell potential of a zinc/air cell? $$ -1.249 V $$ +0.401 V

A patient is injected with a 5.0 $\mu$ M solution of gallium citrate containing radioactive gallium-68 for a PET study. The half-life of gallium-68 is 9.4 hr. How long does it take for the activity of this isotope to drop to 1% of its initial value?

Calcium is a major essential element in the human body. What is the dominant role played by calcium?

Quiz 21: The Main Group Elements: Life and the Periodic Table

Barium is a nonessential element in the human body, but some organisms build exoskeletons using barium sulfate, which has a Ksp of 1.1 ×\times× 10-10 at 25 ∘\circ∘ C. What is the mass of barium in 1.0 L of a saturated solution of barium sulfate at 25 ∘\circ∘ C?

The cation BiO+ is found in some over-the-counter antacids. Draw the Lewis structure of this cation that satisfies the octet rule for both atoms. Based on this Lewis structure, this cation has ________ of nonbonding electrons.

Rhenium-186 has medical applications. It decays by β\betaβ emission. What isotope is formed from this decay?

Thallium-201 is used in cardiac imaging. It decays by electron capture. What isotope is produced when thallium-201 captures an electron?

Hearing aid batteries utilize a zinc/air electrochemical cell. The reduction half-reactions and standard reduction potentials for this cell are given below. What species are oxidized and reduced in the cell reaction? ~~~~~~~~ -1.249 V ~~~~~~~~ +0.401 V

Radioactive tritium, 3H, is used as a tracer in many biological experiments. It decays by β\betaβ emission. What is the product of this decay?

Which element may contribute to sudden infant death syndrome (SIDS) , as it is used as a fire retardant in mattresses?

Lithium is used in the treatment of which disease?

A patient is injected with a 5.0 μ\muμ M solution of gallium citrate containing radioactive gallium-68 for a PET study. The half-life of gallium-68 is 9.4 hr. How long does it take for the activity of this isotope to drop to 1% of its initial value?

The release of radioactive cesium-137 into the environment by the nuclear accident at Chernobyl produced a health hazard because cesium ions can substitute for ________ in plants, making them unsafe for human consumption.

The isotope 18F is used in a range of radio imaging applications. It has a first-order rate constant, k, of 6.30 ×\times× 10-3 min-1. What is the half-life for 18F?

Hearing aid batteries utilize a zinc/air electrochemical cell. The reduction half-reactions and standard reduction potentials for this cell are given below. Write the balanced reaction equation for the cell and report the sum of the stoichiometric coefficients. ~~~~~~~~ -1.249 V ~~~~~~~~ +0.401 V

The isotope 201Th is used in the diagnosis of heart disease. It has a first-order rate constant, k, of 9.49 ×\times× 10-3 h-1. What is the half-life for 201Th?

A radioactive isotope that emits the shortest range particles and therefore would be a good choice for implantation therapy most likely decays via ________

The essential elements found in the human body are classified as major, trace, and ultratrace based on their concentration levels. What are the concentration ranges that define each of these classifications?

Hearing aid batteries utilize a zinc/air electrochemical cell. The reduction half-reactions and standard reduction potentials for this cell are given below. What is the standard cell potential of a zinc/air cell? ~~~~~~~~ -1.249 V ~~~~~~~~ +0.401 V

A patient is injected with a 5.0 μ\muμ M solution of gallium citrate containing radioactive gallium-68 for a PET study. The half-life of gallium-68 is 9.4 hr. How long does it take for the activity of this isotope to drop to 1% of its initial value?

Calcium is a major essential element in the human body. What is the dominant role played by calcium?

Barium is a nonessential element in the human body, but some organisms build exoskeletons using barium sulfate, which has a K_sp of 1.1 $\times$ 10^-10 at 25^$\circ$C. What is the mass of barium in 1.0 L of a saturated solution of barium sulfate at 25^$\circ$C?

The cation BiO⁺ is found in some over-the-counter antacids. Draw the Lewis structure of this cation that satisfies the octet rule for both atoms. Based on this Lewis structure, this cation has ________ of nonbonding electrons.

Rhenium-186 has medical applications. It decays by $\beta$ emission. What isotope is formed from this decay?

Hearing aid batteries utilize a zinc/air electrochemical cell. The reduction half-reactions and standard reduction potentials for this cell are given below. What species are oxidized and reduced in the cell reaction? $$ -1.249 V $$ +0.401 V

Radioactive tritium, ³H, is used as a tracer in many biological experiments. It decays by $\beta$ emission. What is the product of this decay?

A patient is injected with a 5.0 $\mu$ M solution of gallium citrate containing radioactive gallium-68 for a PET study. The half-life of gallium-68 is 9.4 hr. How long does it take for the activity of this isotope to drop to 1% of its initial value?

The isotope ¹⁸F is used in a range of radio imaging applications. It has a first-order rate constant, k, of 6.30 $\times$ 10^-3 min^-1. What is the half-life for ¹⁸F?

Hearing aid batteries utilize a zinc/air electrochemical cell. The reduction half-reactions and standard reduction potentials for this cell are given below. Write the balanced reaction equation for the cell and report the sum of the stoichiometric coefficients. $$ -1.249 V $$ +0.401 V

The isotope ²⁰¹Th is used in the diagnosis of heart disease. It has a first-order rate constant, k, of 9.49 $\times$ 10^-3 h^-1. What is the half-life for ²⁰¹Th?

Hearing aid batteries utilize a zinc/air electrochemical cell. The reduction half-reactions and standard reduction potentials for this cell are given below. What is the standard cell potential of a zinc/air cell? $$ -1.249 V $$ +0.401 V

A patient is injected with a 5.0 $\mu$ M solution of gallium citrate containing radioactive gallium-68 for a PET study. The half-life of gallium-68 is 9.4 hr. How long does it take for the activity of this isotope to drop to 1% of its initial value?