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3 years ago

A radioactive nucleus alpha decays to yield a sodium-24 nucleus in 14.8 hours. What was the identity of the original nucleus?

Chemistry

1 answer:

Rudik [331]3 years ago

5 0

Answer:

2813Al

Explanation:

You know that alpha decay takes place when a α-particle is being ejected from the nucleus of a radioactive isotope.An

α-particle is simply the nucleus of a helium-4 atom. A helium-4 atom has a total of two protons and two neutrons in its nucleus, and two electrons surrounding that nucleus.

In that case, if a α-particle is the nucleus of a helium-4 atom, then it must have a mass number equal to 4, since it has two protons and two neutrons, and a net charge of (2+) since it no longer has the two electrons that the helium-4 atom has.

So, you know that an unknown radioactive isotope decays via alpha decay to yield a sodium-24 nucleus.

A sodium-24 nucleus contains 11 protons and 13 neutrons. This means that you can write

AZX→2411Na+42α

Here A and Z represent the unknown element's mass number and atomic number, respectively.

So, if you take into account the fact that mass number and atomic number must be conserved in a nuclear reaction, you can say that

A=24+4 and Z=11+2

The unknown isotope will thus have

{A=28Z=13

A quick look at the periodic table will show you that the element that has 13 protons in its nucleus is aluminum, Al. This means that you're dealing with aluminum-28, an isotope of aluminum that has 15 neutrons in its nucleus.

The complete nuclear equation will be

2813Al→2411Na+42α

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What will happen if a crystal of ammonium nitrate is added to a supersaturated ammonium nitrate solution? Will it dissolve in wa

romanna [79]

Answer:

It will not dissolve. More crystals will separate from the solution.

Step-by-step explanation:

If you add a crystal of ammonium nitrate to a supersaturated solution of the solute, it will not dissolve.

Instead, it will act as a "seed" on which more ammonium nitrate crystals will form.

They will separate from the solution as long, colourless, needle-like crystals until the solution is no longer supersaturated.

5 0

3 years ago

Priscilla was building a circuit that used copper wires to connect a battery to a light bulb. As she connected the final wire fr

algol [13]

Answer:

The voltage or potential difference

Explanation:

What makes current flow in a circuit is the voltage or the potential difference.

This force is supplied by the battery or the mains electrical circuit.

Every circuit requires the voltage to drive current through
When a circuit is complete, the battery is able to overcome any resistance by the generating enough voltage which is the force to drive the current through.

7 0

2 years ago

0.023 M solution of perchloric acid

kogti [31]

The original question is to find the pH and the pOH of 0.023 M of perchloric acid.

Answer:
pH = 1.638
pOH = 12.362

Explanation:
1- getting the pH:
pH can be calculated using the following rule:
pH = -log[H+]
Since the given solution is an acid, this means that [H+] is the same as the concentration of the solution.
This means that:
[H+] = 0.023
Substitute in the above equation to get the pH as follows:
pH = -log[0.023]
pH = 1.638

2- getting the pOH:
We know that:
pH + pOH = 14
We have calculated that pH = 1.638.
Substitute in the above equation to get the pOH as follows:
pOH + 1.638 = 14
pOH = 14 - 1.638
pOH = 12.362

Hope this helps :)

5 0

3 years ago

How are the following aspects of a reaction affected by the addition of a catalyst? 1) activation energy of the reverse reaction

snow_tiger [21]

These are four questions and four answers.

Answers:

1) activation energy of the reverse reaction

b. Decreased

2) Rate of the forward reaction

a. Increased

3) Rate of the reverse reaction

a. Increased

4) Activation energy of the forward reaction

b. decreased

Explanation:

Activarion energy is the energy required by the reactants to form the intermediate transition state and become products.

Catalysts are substances that change the path of the chemical reactions, lowering the activation energy, and thus speeding up the rate of the reactions, since the products can reach the new lower activation energy faster.

The equilibrium reactions are the chemical process in which two reactions, the forward and the reverese reactions, occur simultaneously and at the same rate. The equlibrium reactions may be represented by:

A ⇄ B

Where A → B is the direct or forward reaction, and A ← B is the reverse reaction (note the inversed arrow, from right to left).

For the direct reaction A represents the reactants and B represents the products. On the other hand, B represents the reactants and A represents the reactants of the reverse reaction and A. This, is A is the reactant of the forward reaction and the product of the reverse reaction, while B is the reactant of the reverse reaction and the product of the forward reaction.

Since, the addition of a catalyst lowers the activation energy of the process, the new activation energy is lower for both the forward and the reverse reaction, meaning that:

1. The activation energy of the reverse reaction is decreased (option b. of the first question)

2. The rate of the forward reaction is increased (option a. of the second question)

3. The rate of the reverse reaction is increased (option a. of the third question).

4. Activation energy of the forward reaction is decreased (option b. of the fourth question).

In summary, the addition of a catalyst decreases the activation energy for both forward and reverse reactions, and increases the rate of both forward and reverse reactions.

3 0

3 years ago

Read 2 more answers

Convert 22 ml in to liters

prisoha [69]

Answer:

0.022

Explanation:

milliter (ml) = 1 cubic centimeter (cc)= 0.001 liters (l) = 0.000001 cubic meters (m3).

1 ml = 0.061024 cubic inches (in3) ; 1 in3 = 16.4 ml.

1 ml = 0.000035 cubic feet (ft3); 1 ft3 = 28,317 ml.

1 ml = 2.64 x 10-4 U.S. gallons (gal); 1 gal = 4.55 x 103 ml.

8 0

2 years ago