Answer:
<em>To calculate the average atomic mass, multiply the fraction by the mass number for each isotope, then add them together.</em>
<em>hope this helps</em><em> </em><em><</em><em>3</em>
Ln(P2/P1) = (L/R).(1/T1 - 1/T2)
<span>with P1 = 1 atm, P2 = 45.9 atm, R = 8.314 J/mol.K, T1 = 452.15 K, T2 = 695.15 K. This gave the latent heat L as 41.2 kJ/mol.K. </span>
<span>Using this value, and calculating the vapour pressure at 120°C = 393.15 K </span>
<span>ln(P2) = (41.2 x 10^3/8.314).(1/452.15 - 1/393.15) </span>
<span>which gives the vapour pressure P2 as 0.1931 atm = 146.7 torr. </span>
This is in the assumption that these are the only 2 isotopes. This means that:
abundance of Li-6 = X
abundance of Li-7 = 1-X
Hence from your equations
6.9409 = (X * 6.015121amu) + ((1-X) * <span>7.016003amu</span>)
Solve for X = 0.075 or 7.50%
Answer:
B, C
Explanation:
The atoms or ions with the valid Lewis dot structures are B and C.
In A;
The Lewis structure of the carbon is correct. Each of the four dots represent the four valence electrons.
The nitrogen with one dot on top, left and to the bottom and has a charge of minus 3 is wrong. For it to have a charge of -3 it must have 8 lewis dots ( two on the top, right, bottom and to the left)
The nitrogen with four dots (on top, right, bottom and to the left) is wrong.
In B;
An oxygen has two dots on top and bottom and one dot to the left and to the right. This is correct , the 6 dots represent the valence electrons of oxygen.
In C;
A carbon has two dots on top, right, bottom and to the left and a charge of plus four. This is correct because the charge indicates that it has gained four extra electrons so its valence electrons is now 8.
In D;
An oxygen has two dots on top, left and to the bottom and a charge of minus 2. This is wrong because the lewis dots are incomplete. Two dots are missing.
