Answer:
What information can climatologists learn from fossils? Fossils of plants and animals can show adaptations that organisms had for a particular type of climate that existed millions of years ago. Climatologists look at many pieces of evidence to study climate change. These pieces of evidence can support each other.
Explanation:
,.,
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>
Answer:
exp:
two ways of activities performed by a veterinarian is:
performing surgery and checkups.
Answer is: the osmotic pressure of aqueous solution of aspirin is 0.0407 atm.
m(C₉H₈O₄) = 75 mg ÷ 1000 mg/g = 0.075 g.
n(C₉H₈O₄) = 0.075 g ÷ 180.16 g/mol.
n(C₉H₈O₄) = 0.000416 mol.
c(C₉H₈O₄) = 0.000416 mol ÷ 0.250 L.
c(C₉H₈O₄) = 0.00167 M; concentration of solution.
T(C₉H₈O₄) = 25°C = 298.15 K; temperature in Kelvins.
R = 0.08206 L•atm/mol•K; universal gas constant.
π = c(C₉H₈O₄) • T(C₉H₈O₄) • R.
π = 0.00167 mol/L • 298.15 K • 0.08206 L•atm/mol•K.
π = 0.0407 atm.
