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5 days ago

Heavy nuclides with too few neutrons to be in the band of stability are most likely to decay by what mode?

Chemistry

1 answer:

Anarel [2.7K]5 days ago

6 0

Answer:

Positron emission

Explanation:

In positron emission, a proton transforms into a neutron. This alteration results in a daughter nucleus with its mass number increased by 1, while the atomic number remains unchanged. The formation of a new neutron boosts the neutron count in the daughter nucleus, thus enhancing the N/P ratio.

Concurrently, a positron is emitted along with an anti-neutrino to ensure spin conservation.

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66.667 mL of 3.000 M H2SO4 (aq) solution was neutralized by the stoichiometric amount of 4.000 M Al(OH)3 solution in a coffee cu

eduard [2645]

Answer:

$\large \boxed{\Delta_{\textbf{r}}H =\text{-4600 J$\cdot$ mol}^{-1}}$

Explanation:

This scenario is unrealistic since Al(OH)₃ is not soluble in water.

The question consists of two parts:

A. Stoichiometry — where we determine volumes, masses, and moles for the products

B. Calorimetry — where we assess the enthalpy of the reaction.

A. Stoichiometry

1. Determine the volume of Al(OH)₃

(a) The balanced chemical equation:

2Al(OH)₃ + 3H₂SO₄ ⟶ Al₂(SO₄)₃ + 6H₂O

M/V: 66.667

c/mol·L⁻¹: 4.000 3.000

(b) Moles of H₂SO₄

$\rm \text{66.667 mL H$_{2}$}SO_{4} \times \dfrac{\text{3.000 mmol H$_{2}$SO}_{4}}{\text{1 mL H$_{2}$SO}_{4}} = \text{200.00 mmol H$_{2}$SO}_{4}$

(c) Moles of Al(OH)₃

The molar ratio stands at 2 mmol Al(OH)₃: 3 mmol H₂SO₄

$\text{Moles of Al(OH)}_{3} = \text{200.00 mmol of H$_{2}$SO}_{4} \times \dfrac{\text{2 mmol Al(OH)}_{3}}{\text{3 mmol H$_{2}$SO}_{4}}\\\\= \text{133.33 mmol Al(OH)}_{3}$

(d) Volume of Al(OH)₃

$\text{Moles of Al(OH)}_{3} = \text{200.00 mmol of H$_{2}$SO}_{4} \times \dfrac{\text{1 mL Al(OH)}_{3}}{\text{4 mmol H$_{2}$SO}_{4}} = \text{50.000 mL Al(OH)}_{3}$

B. Calorimetry

This reaction has two energy exchanges.

q₁ = heat from the reaction

q₂ = heat used to heat the calorimeter

q₁ + q₂ = 0

nΔH + mCΔT = 0

Data:

Moles of Al₂(SO₄)₃ = 0.066 667 mol

C = 1.10 J°C⁻¹g⁻¹

T_initial = 22.3 °C

T_final = 24.7 °C

Calculations

(a) Mass of solution

Assume solutions are as dense as water (though not realistic).

Mass of sulfuric acid solution = 66.667 g

Mass of aluminium hydroxide solution = 50.000

TOTAL = 116.667 g

(b) ΔT

ΔT = T_final - T_initial = 24.7 °C - 22.3 °C = 2.4°C

(c) ΔH

$\begin{array}{ccccl}n\Delta H & +& mC \Delta T& = &0\\\text{0.066 667 mol }\times \Delta H& + & \text{116.667 g} \times 1.10 \text{ J$^{\circ}$C$^{-1}$g$^{-1}$} \times 2.4 \, ^{\circ}\text{C} & = & 0\\0.066667 \Delta H \text{ mol} & + & \text{310 J} & = & 0\\&&0.066667 \Delta H \text{ mol} & = & \text{-310 J} & & \\\end{array}\\$

$\begin{array}{ccccl}& &\Delta H & = & \dfrac{\text{-310 J}}{\text{0.066667 mol}}\\\\& &\Delta H & = & \textbf{-4600 kJ/mol}\\\end{array}\\\large \boxed{\mathbf{\Delta_{\textbf{r}}H} =\textbf{-4600 J$\cdot$ mol}^{\mathbf{-1}}}$

This result appears nonsensical, but it is derived from your given figures.

6 0

1 month ago

In which of these statements are protons, electrons, and neutrons correctly compared?

Alekssandra [2891]

<span>Quarks exist inside protons and neutrons but are not components of electrons. Quarks are subatomic particles that possess mass and fractional (non-integer) electric charge. Protons and neutrons are composed of quarks, whereas electrons are not, since electrons are considered energy carriers with charge rather than massive matter. Because quarks have mass, they cannot be part of electrons.</span>

5 0

20 days ago

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An atom of the element zinc has an atomic number of 30 and a mass number of 65. How many protons does an uncharged zinc atom hav

KiRa [2857]

Answer: The correct option is, 30 protons

Explanation:

Element = Zinc

Atomic number = 30

Atomic mass number = 65

Recall that the atomic number equals the number of electrons and protons.

Atomic number = Number of electrons = Number of protons = 30

Number of neutrons = Atomic mass - Number of protons = 65 - 30 = 35

Therefore, an uncharged zinc atom has 30 protons.

6 0

22 days ago

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Global Precipitation Measurement (GPM) is a tool scientists use to forecast weather. Which statements describe GPM? Select three

Anarel [2728]

Answer:

This is a satellite that gathers information on rainfall and snow.

• Its orbit spans 90 percent of the Earth's surface.

• The sensors detect microwaves.

Explanation:

Right on track

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9 days ago

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How is the periodic law demonstrated in halogens

Anarel [2728]

Halogens are characterized as a group of 7 on the periodic table. Each of these elements has 7 valence electrons, needing just one additional electron to fill their outer shell, resulting in their high reactivity. Moreover, the periodic law indicates that when the elements are arranged by increasing atomic number, similar patterns in their properties emerge. Thus, halogens exhibit comparable behaviors during chemical reactions with one another, which is indeed accurate.

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20 days ago

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