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:
THE VOLUME OF THE BALLOON IS 1.45 L
Explanation:
At sea level:
Volume = 2 L
Pressure = 1 atm
Temperature = 12 °C
At 30000 ft altitude:
Pressure = 0.30 atm
Temperature = -55°C
Volume = unknown
Using the general gas formula:
P1 V1 / T1 = P2 V2 / T2
Re-arranging the formula by making V2 the subject of the equation, we have;
V2 = P1 V1 T2 / T1 P2
V2 = 1 * 2 * 12 / 0.30 * 55
V2 = 24 / 16.5
V2 = 1.45 L
The volume of the balloon at the temperature of -55 C and 0.30 atm is 1.45 L
= 30802.53 im pretty sure if im wrong let me know its the best i can do :/
Answer:
The resulting solution contains approximately 666 g of water.
Explanation:
In the initial solution we have:
1g salt : 8g sugar : 200g water
This means that the ratios are:
In the final solution we have:
5g salt: xg sugar: yg water
The new ratios are:
Now we can calculate the amount of sugar in the final solution:
Finally, we calculate the amount of water:
Answer:
CaCl₂(s) ⟶ Ca²⁺(aq) + 2Cl⁻(aq)
Explanation:
When the calcium chloride dissolves. the calcium and chloride ions leave the surface of the solid and go into solution as hydrated ions.
