Answer:
an atom with a half-filled subshell - hydrogen
an atom with a completely filled outer shell - argon
an atom with its outer electrons occupying a half-filled subshell and a filled subshell- copper
Explanation:
The outermost shell or the valence shell of the atom is the last shell in the atom. Chemical reactions occur at this outer most shell. The number of electrons on the outermost shell of an atom determines the group to which it belongs in the periodic table as well as its chemical properties.
Hydrogen has a half filled 1s sublevel. Only one electron is present in this sublevel.
Let us consider argon
1s2 2s2 2p6 3s2 3p6
The outermost ns and np levels are completely filled. Thus the outermost shell is completely filled.
In the last case; let us look at the electronic configuration of nitrogen;
1s2 2s2 2p3
The outermost 2p subshell is exactly half filled while the 2s sublevel is fully filled. The outermost shell of nitrogen is made up of 2s2 and 2p3 sublevels.
Avagadros constant states that 1 mol of any substance is made of 6.022 x 10^23 units.
These units could be atoms making up elements or molecules making up compounds.
1 mol of molecular oxygen (O2) is made of 6.022 x 10^23 molecules of O2
The mass of 1 mol of O2 is 32 g/mol
This means that the number of oxygen molecules in 32 g are 6.022 x 10^23 molecules
Therefore in 7.36 g of oxygen gas there are - 6.022 x 10^23 /32 g/mol x 7.36 g = 1.39 x 10^23 oxygen molecules
Answer is 1.39 x 10^23 oxygen molecules
Missing in your question :
Concentration by (M):
Xy: y: X
initial 0.2 0.3 0.3
change +X -X -X
equilibrim (0.2+x) (0.3-x) (0.3-x)
according to Kc formula: when Kc = 0.2
Kc = [XY]/[X]*[Y]
0.2 = (0.2+x) / (0.3-x)*(0.3-x)
0.2=(0.2+x) / (0.3-x)^2 by solving this equation
0.2*(0.3-x)^2 = 0.2+x
0.2* (0.09-0.6x+x^2)= 0.2 +x
0.0018 - 0.12 X +0.2X^2 = 0.2 + X
0.2X^2 -1.12 X -0.1982 = 0
∴X= 0.17
∴[XY] = 0.2 + 0.17 = 0.37 m
∴[X] = 0.3 - 0.17 =0.13 m
∴[y] = 0.3 - 0.17 = 0.13 m
Answer:
Hydrogen peroxide should be stored in
1) a cool environment
2) with amber bottles away from sunlight
3) with little drops of sodium phosphate
Explanation:
It has been confirmed that heat and light aids in the decomposition of hydrogen peroxide according to the equation; 2H2O2→2 H2O + O2.
This means that hydrogen peroxide must be stored in a cool place. This will reduce its rate of decomposition. Secondly, it should be stored in amber bottles away from light since light also aids in its decomposition.
Thirdly, drops of sodium phosphate may be added to prevent its catalytic decomposition during storage.
