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ipn [44]
3 years ago
7

PLEASE HELP

Chemistry
1 answer:
lisabon 2012 [21]3 years ago
6 0

Answer:

The answer is B.

Explanation:

Trust me i took the test already its b.

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Which of the following statements regarding alpha particles are true? Check all that apply.a. Alpha particles have a mass number
egoroff_w [7]

Answer:

The only true statement is:

  • a. <u><em>Alpha particles have a mass number of 4</em></u>

Explanation:

<em>Alpha particles</em> are radiactive particles equivalent to a helium nucleus, so they have two protons and two neutrons.

Hence, alpha particles, α, are represented as:

  • ⁴₂He

The superscript 4 to the left of the chemical symbol is the <em>mass number:</em> 2 protons + 2 neutrons = 4

The subscript 2 to the left of the chemical symbol is the atomic number: 2 protons = 2.

Hence, the statement "a. Alpha particles have a mass number of 4" is true.

As for the other statements, you have:

<em>b. Alpha particles have a nulear charge of +1:</em> <u>false</u>

Since, these particles are the nucleous of the helium atom, the nuclear charge equals the number of protons of this atom: +2. Hence, the statement is false.

c. <em>Alpha particle formation is accompanied by the conversion of a proton into a neutron</em> and d. <em>Alpha particle formation is accompanied by the conversion of a neutron into a proton</em>. <u>(both false</u>)

The conversion of a protons into a neutrons and the conversion of a neutron into a proton are product of other kind of radiactive desintegrations.

  • The conversion of a proton into a neutron involves the emission of a positron ( particle with same mass as the electron but positive charge) from the nucleus, which is represented as ⁰₊₁β.

  • The conversion of a neutron into a proton involves the emssion of an electron from the nucleus, which is the emission of a beta particle represented as ⁰₋₁β.

Therefore, these last two statements are also false.

4 0
3 years ago
how many milliliters of 1.50 m hno3 contain enough nitric acid to dissolve an old copper penny with a mass of 3.94 g?
Lerok [7]
Molar mass HNO₃ = 63.0 g/mol

number of moles = 3.94 / 63.0 => 0.0625 moles

Volume = moles / molarity

V = 0.0625 / 1.50

V = 0.04166 L x 1000 = 41.66 mL

hope this helps!

5 0
3 years ago
After a covalent bond has stabilized an atom, the atom will have
padilas [110]
<span>A full valence electron shell.</span>
6 0
3 years ago
Read 2 more answers
Calculate the pH of the following simple solutions:
IceJOKER [234]

Answer :

(1) pH = 1.27

(2) pH = 13.35

(3) The given solution is not a buffer.

Explanation :

<u>(1) 53.1 mM HCl</u>

Concentration of HCl = 53.1mM=53.1\times 10^{-3}M

As HCl is a strong acid. So, it dissociates completely to give hydrogen ion and chloride ion.

So, Concentration of hydrogen ion= 53.1\times 10^{-3}M

pH : It is defined as the negative logarithm of hydrogen ion concentration.

pH=-\log [H^+]

pH=-\log (53.1\times 10^{-3})

pH=1.27

<u>(2) 0.223 M KOH</u>

Concentration of KOH = 0.223 M

As KOH is a strong base. So, it dissociates completely to give hydroxide ion and potassium ion.

So, Concentration of hydroxide ion= 0.223 M

Now we have to calculate the pOH.

pOH=-\log [OH^-]

pOH=-\log (0.223)

pOH=0.65

Now we have to calculate the pH.

pH+pOH=14\\\\pH=14-pOH\\\\pH=14-0.65=13.35

<u>(3) 53.1 mM HCl + 0.223 M KOH</u>

Buffer : It is defined as a solution that maintain the pH of the solution by adding the small amount of acid or a base.

It is not a buffer because HCl is a strong acid and KOH is a strong base. Both dissociates completely.

As we know that the pH of strong acid and strong base solution is always 7.

So, the given solution is not a buffer.

5 0
3 years ago
A 15.0 L tank of gas is contained at a high pressure of 8.20 x 10^4 torr. The tank is opened and the gas expands into an empty c
Inga [223]

Answer:

20.5torr

Explanation:

Given parameters:

V₁  = 15L

P₁  = 8.2 x 10⁴torr

V₂ = 6 x 10⁴L

Unknown:

P₂  = ?

Solution:

To solve this problem we have to apply the claims of Boyle's law.

Boyle's law is given mathematically as;

            P₁ V₁   = P₂V₂

where P₁ is the initial pressure

          V₁ is the initial volume

           P₂ is final pressure

           V₂ is final volume

   8.2 x 10⁴  x 15  = P₂  x 6 x 10⁴

         P₂  = 20.5torr

5 0
3 years ago
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