Answer:
The statement that best describes the trend in first ionization enery of elements on the periodic table is:
It generally decreases down a group because valence electrons are farther from the nucleus.
The first ionization energy measures how difficult is to release an electron from the outermost shell. The higher the ionization energy the more difficult it is to release an electron, the lower the ionication energy the easier to release an electron.
As the atomic number of the atom increases (which is what happens when you go down a group) the furthest the outermost shell of electrons will be (the size of the atoms increases) and so those electrons require less energy to be released, which means that the ionization energy decreases.
Hope it helps!
Answer:

Explanation:
Given data:
Mass of mixture = 454 kg
Initial temperature is 10°C
Heat added is Q = 121300 kJ
Heat capacity (Applesuace) at 32.8°C is 4.02kJ/kg K
From heat equation we have



Putting all value to get required final temperature value


Two [hydrogen] atoms and one [oxygen] atom
Answer:
1425 mmHg.
Explanation:
The following data were obtained from the question:
Initial volume (V1) = 1.5 L
Initial pressure (P1) = 1 atm
Final volume (V2) = 0.8 L
Final pressure (P2) =?
Next, we shall determine the final pressure of the gas by using the Boyle's law equation as follow:
P1V1 = P2V2
1 × 1.5 = P2 × 0.8
1.5 = P2 × 0.8
Divide both side by 0.8
P2 = 1.5/0.8
P2 = 1.875 atm
Finally, we shall convert 1.875 atm to mmHg.
This can be obtained as follow:
1 atm = 760 mmHg
Therefore,
1.875 atm = 1.875 × 760 = 1425 mmHg.
Therefore, the new pressure of the gas is 1425 mmHg.
Calculating for the moles of H+
1.0 L x (1.00 mole / 1 L ) = 1 mole H+
From the given balanced equation, we can use the stoichiometric ratio to solve for the moles of PbCO3:
1 mole H+ x (1 mole PbCO3 / 2 moles H+) = 0.5 moles PbCO3
Converting the moles of PbCO3 to grams using the molecular weight of PbCO3
0.5 moles PbCO3 x (267 g PbCO3 / 1 mole PbCO3) = 84.5 g PbCO3