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
butalik [34]
3 years ago
6

The element lanthanum has two stable isotopes, lanthanum-138 with an atomic mass of 137.9 AMU and lanthanum-139 with an atomic m

ass of 138.9 AMU.
From the atomic weight of La = 138.9, one can conclude that:

A. there is an isotope of lanthanum with an atomic mass of 138.9
B. lanthanum-139 has the highest percent natural abundance
C. lanthanum-138 has the highest percent natural abundance
D. both isotopes have the same percent natural abundance
Chemistry
1 answer:
dmitriy555 [2]3 years ago
7 0

Answer:

A. there is an isotope of lanthanum with an atomic mass of 138.9

Explanation:

By knowing the different atomic masses of both Lanthanum atoms, we can not tell anything about their occurence in nature. Therefore, all the last three options are incorrect. Because, the atomic mass does not tell anything about the availability or natural abundance of an element.

Now, the isotopes of an element are those elements, which have same number of electrons and protons as the original element, but different number of neutrons. Therefore, they have same atomic number but, different atomic weight or atomic masses.

Hence, by looking at an elements having same atomic number, but different atomic masses, we can identify them as isotopes.

Thus, the correct option is:

<u>A. there is an isotope of lanthanum with an atomic mass of 138.9.</u>

You might be interested in
What is the difference between Hydrolysis and Hydration?​
Grace [21]
Hydrolysis involves the reaction of water with another compound.Hydrolysis is the process in which the bond breaks due to addition of water whereas in hydration there is just addition of water, the molecule doesn’t break down.
7 0
3 years ago
Read 2 more answers
Which of these events explains the presence of the volcano?
kenny6666 [7]
I would say the answer is C

hope this helps :)
5 0
3 years ago
Read 2 more answers
Regarding the Lyman series of hydrogen, calculate the frequency of the n = 5 line.
zvonat [6]
The Lyman series can be expressed in the formula <span><span>1/λ</span>=<span>RH</span><span>(1−<span>1/<span>n2</span></span>) where </span><span><span>RH</span>=1.0968×<span>107</span><span>m<span>−1</span></span>=<span><span>13.6eV</span><span>hc

</span></span></span></span>Where n is a natural number greater than or equal to 2 (i.e. n = 2,3,4,...). Therefore, the lines seen in the image above are the wavelengths corresponding to n=2 on the right, to n=∞on the left (there are infinitely many spectral lines, but they become very dense as they approach to n=∞<span> (Lyman limit), so only some of the first lines and the last one appear).
 The wavelengths (nm) in the Lyman series are all ultraviolet
:2 3 4 5 6 7 8 9 10 11
 Wavelength (nm) 121.6 102.6 97.3 95 93.8 93.1 92.6 92.3 92.1 91.9 91.18 (Lyman limit)
In your case for the n=5 line you have to replace "n" in the above formula for 5 and you should get a value of 95 x 10^-9 m for the wavelength. then you have to use the other equation that convert wavelength to frequency. </span>
4 0
3 years ago
Which would exert more pressure on the floor, a 100kg man wearing snow shoes or a 60kg woman wearing high heels? PLEASE EXPLAIN
iris [78.8K]

Pressure can be defined as the force acting on a perpendicular surface per unit area.

Force exerted by a man of mass 100 kg wearing snow shoes = m.a

Where m = mass of the man = 100 kg

a = acceleration due to gravity= 9.8 m/s^{2}

Force exerted by the man of mass 100 kg = 100 kg(9.8 m/s^{2}) = 980 N

Force exerted by woman of mass 60 kg = 60 kg(9.8 m/s^{2}) = 588 N

Force exerted by 100 kg man is greater than that exerted as 60 kg woman. The area on which this force is acting determines the pressure. Pressure is inversely proportional to the area on which the force acts. Therefore, the pressure exerted by 100 kg man wearing snow shoes is less than the pressure exerted by a 60 kg woman woman wearing high heels as the force acts over a larger area when the man wears snow shoes when compared to the force exerted over a smaller area in case of the woman wearing high heels.

5 0
3 years ago
(First to answer gets some good) Order the following components of the universe from largest to smallest: Moon, planet,universe,
cluponka [151]

Answer:

Universe, galaxy, solar system, star, planet, moon and asteroid.

Explanation:

You're welcome!

7 0
3 years ago
Other questions:
  • If element X has 25 protons, how many electrons does it have?
    6·2 answers
  • What material is the buddha statue gautama buddha belum caves?
    12·1 answer
  • An element's atomic number is 45. how many electrons would an atom of this element have?
    9·1 answer
  • I'll mark brainliest if you can answer this quick and correctly only correct cause i don't accept bad answers or i'll report you
    14·1 answer
  • What is the molarity of a solution that contains 25 g of HCl in 150 mL of solution? (The molar mass of HCl is 36.46 g/mol.)
    14·2 answers
  • What is the answer?
    12·1 answer
  • Which element is always found in impure form naturally
    10·2 answers
  • 2 NaOH + H2SO4 ------&gt; 2 H2O + Na2SO4
    14·1 answer
  • type of environmental factors such as temperature or amount of light that might affect an organism's phenotype is___________​
    8·1 answer
  • Which of the following equations correctly describes how to calculate net income? a. net income = (cost of goods sold) - (net sa
    5·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!