1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
Nitella [24]
3 years ago
12

How many neutrons does element X have if its atomic number is 30 and its mass number is 70?

Chemistry
1 answer:
Yanka [14]3 years ago
3 0
The answer is 40.

We can solve this by finding out the number of protons, and neutrons. Atomic number of an element means the number of protons in that element. So, the atom has 30 protons if the atomic number is 30.

On the other hand, mass number is the total number of protons and neutrons, but not electrons, because they're too light comparing to the other 2. Therefore, we can simply solve the number of neutrons in the atom by subtracting the number of protons from the mass number. 70 - 30 = 40.

Therfore, the number of neutrons is 40.
You might be interested in
Consider a voltaic cell where the anode half-reaction is Zn(s) → Zn2+(aq) + 2 e− and the cathode half-reaction is Sn2+(aq) + 2 e
notsponge [240]

<u>Answer:</u> The concentration of Sn^{2+} in the cell is 9.0\times 10^{-3}M

<u>Explanation:</u>

We are given:

<u>Oxidation half reaction:</u>  Zn(s)\rightarrow Zn^{2+}(aq.)+2e^-   E^o_{Zn^{2+}/Zn}=-0.76V

<u>Reduction half reaction:</u>  Sn^{2+}(aq.)+2e^-\rightarrow Sn(s)   E^o_{Sn^{2+}/Sn}=-0.136V

The substance having highest positive E^o potential will always get reduced and will undergo reduction reaction. Here, fluorine will undergo reduction reaction will get reduced.

Here, tin will undergo reduction reaction and will get reduced.

Oxidation reaction occurs at anode and reduction reaction occurs at cathode.

To calculate the E^o_{cell} of the reaction, we use the equation:

E^o_{cell}=E^o_{cathode}-E^o_{anode}

Putting values in above equation, we get:

E^o_{cell}=-0.136-(-0.76)=0.624V

To calculate the EMF of the cell, we use the Nernst equation, which is:

E_{cell}=E^o_{cell}-\frac{0.059}{n}\log \frac{[Mn^{2+}]}{[Cu^{2+}]}

where,

E_{cell} = electrode potential of the cell = 0.660 V

E^o_{cell} = standard electrode potential of the cell = +0.624 V

n = number of electrons exchanged = 2

[Zn^{2+}]=2.5\times 10^{-3}M

[Sn^{2+}] = ?

Putting values in above equation, we get:

0.660=0.624-\frac{0.059}{2}\times \log(\frac{2.5\times 10^{-3}}{[Sn^{2+}})

[Sn^{2+}]=9.0\times 10^{-3}M

Hence, the concentration of Sn^{2+} ions is 9.0\times 10^{-3}M

3 0
3 years ago
What will determine the number of moles in a sample
julsineya [31]

Answer:

weigh it and divide the weight by the molecular weight. :) good luck!!

Explanation:

3 0
3 years ago
Read 2 more answers
What is the definition of Amplitude?
katen-ka-za [31]

Answer:

the maximum extent of a vibration or oscillation, measured from the position of equilibrium.

Explanation:physics

4 0
3 years ago
How was Bohr’s atomic model different from Rutherford’s atomic model?
Aleks04 [339]

C is the answer.

It says on the third picture that Bohr refined Rutherford's model by giving distinct orbits for the electrons with distinct radii.


3 0
3 years ago
Read 2 more answers
What chemicals need to make liquid bakelite ?
Jet001 [13]
It begins with heating of phenol and formaldehyde in the presence of a catalyst such as hydrochloric acid, zinc chloride, or the base ammonia. This creates a liquid condensation product, referred to as Bakelite A, which is soluble in alcohol, acetone, or additional phenol.
5 0
3 years ago
Other questions:
  • What are 3 Properties of Convalent electrons
    15·1 answer
  • What type of chemical bond would form between an atom of carbon (C) and an atom of nitrogen (N). Explain specifically why this t
    5·1 answer
  • Which accurately represents these building blocks of matter from the smallest to the largest?
    5·1 answer
  • PLEASE HELLLLOOPLPPPPP
    13·2 answers
  • a 125g bar of aluminum at 22 degrees celsius. determine the final temperature of the aluminum, if the amount of energy applied i
    7·1 answer
  • Helpppppppppppppp please
    8·1 answer
  • Give valency of the cation and anion in zinc sulphate​
    11·1 answer
  • Vitamin C is a covalent compound with the molecular
    13·1 answer
  • A) melissa planted more seeds than juan.
    7·2 answers
  • An airplane flew 3043 km from Houston to Seattle in 5.5 hours. What was the average speed, in m/s rounded to the nearest hundred
    14·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!