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3 years ago

Which radioisotope is a beta emitter?(1) 90Sr (3) 37K(2) 220Fr (4) 238U

1 answer:

4 0

The answer is (1) 90 Sr. The definition of beta decay is that a type of radioactive decay in which one proton will change to one neutron and release one electron inside the nucleus. And 90Sr is a common beta emitter.

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Relate the number of protons in the nucleus of an atom to the properties of matter.

Sauron [17]

Answer:

The number of electrons, in turn, determines the chemical properties of the atom. Protons contribute to the mass of an atom and provide the positive charge to the nucleus. The number of protons also determines the identity of the element

4 0

3 years ago

PLEASE HELPPP

rusak2 [61]

Answer; molecule

Explanation:

5 0

3 years ago

How to find protons, neutrons, electrons of an element.

Zina [86]

Find your element on the periodic table. Locate the element’s atomic number.
Determine the number of electrons. Look for the atomic mass of the element. Subtract (-) the atomic number from the atomic mass

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3 years ago

Which of the following is NOT a postulate of the Kinetic Molecular Theory?

kotegsom [21]

Answer:

"3. Energy can either be destroyed or created. Its goes from one form to another."

Explanation:

The third answer choice, "3. Energy can either be destroyed or created. Its goes from one form to another. " is related to the Law of Conservation of Energy from thermodynamics. Is it not a postulate of the Kinetic Molecular Theory.

"1. Average Kinetic Energy of the system is a measure of the temperature of the system."

Postulate of Kinetic Molecular Theory $\checkmark$

The average kinetic energy of the system is measured by its temperature and nothing else

"2. Energy is conserved in the collisions between gas molecules.."

Postulate of Kinetic Molecular Theory $\checkmark$

All collisions between gas molecules are perfectly elastic, meaning no energy is lost

"3. Energy can either be destroyed or created. Its goes from one form to another.

$\times$ NOT a Postulate of Kinetic Molecular Theory

Related to Conservation of Energy from thermodynamics

"4. Gases travel in straight line until they collide with other gas molecules"

Postulate of Kinetic Molecular Theory $\checkmark$

All gas molecules will travel in a straight line until they collide with other gas molecules or some object (e.g. a container)

8 0

2 years ago

Cu20(s) + C(s) - 2Cu(s) + CO(g)

Romashka-Z-Leto [24]

Answer:

That means Cu2O is limiting reagent and C is excess reagent

Explanation:

Based on the reaction, 1 mole of Cu2O reacts per mole of C. The ratio of reaction is 1:1.

To solve this question we need to convert the mass of each reactant to moles. The reactant with the lower amount of moles is limiting reactant and the excess reactant is the reactant with the higher number of moles.

Moles Cu2O -Molar mass: 143.09 g/mol-

114.2g Cu2O * (1mol / 143.09g) = 0.798 moles Cu2O

Moles C -Molar mass: 12.01g/mol-

11.1g C * (1mol / 12.01g) = 0.924 moles C

<h3>That means Cu2O is limiting reagent and C is excess reagent</h3>

6 0

3 years ago