The third equation is properly balanced.
To figure this out, set up tables to check if each element has the same amount on both sides. If you do this for the third equation, copper, hydrogen, oxygen, and nitrogen are all balanced,
The first equation is incorrect due to the fact Iron, Fe, is not balanced on both sides. This is shown by the subscripts given.
The second equation is incorrect as Sulfur is not properly balanced and neither is sodium.
The fourth equation is incorrect as Aluminum is not properly balanced. On the reactants side, Aluminum is 4 while on the products, Aluminum is 8.
Hope this helps!
Answer:
The correct statements that you must check are:
- The oxygen atom has a greater attraction for electrons than the hydrogen atom does (second statement).
- The electrons of the covalent bond are not shared equally between the hydrogen and oxygen atoms (fourth statement).
Explanation:
Electronegativity is the relative ability of an atom to pull the electrons in a covalent bond.
Hydrogen has an electronegativity of 2.20 and oxygen has 3.44. That means that oxygen attracts the electrons more strongly than hydrogen does (second statement).
As consequence, the electrons in the covalent bond H - O of water are not shared equally (fourth statement): the electron density will be higher around the O atoms.
Of course, this discards the statement telling that hydrogen atom attracts electrons much more strongly than the oxygen atom, and the statement telling that hydrogen and oxigen have same electronegativity.
Such difference in electron densities creates a dipole moment, so you discard the last statement (that the water dipole moment is equal to zero).
<span>361.4 pm is the length of the edge of the unit cell.
First, let's calculate the average volume each atom is taking. Start with calculating how many moles of copper we have in a cubic centimeter by looking up the atomic weight.
Atomic weight copper = 63.546
Now divide the mass by the atomic weight, getting
8.94 g / 63.546 g/mol = 0.140685488 mol
And multiply by Avogadro's number to get the number of atoms:
0.140685488 * 6.022140857x10^23 = 8.472278233x10^22
Now examine the face-centered cubic unit cell to see how many atoms worth of space it consumes. There is 1 atom at each of the 8 corners and each of those atoms is shared between 8 unit cells for for a space consumption of 8/8 = 1 atom. And there are 6 faces, each with an atom in the center, each of which is shared between 2 unit cells for a space consumption of 6/2 = 3 atoms. So each unit cell consumes as much space as 4 atoms. Let's divide the number of atoms in that cubic centimeter by 4 to determine the number of unit cells in that volume.
8.472278233x10^22 / 4 = 2.118069558x10^22
Now calculate the volume each unit cell occupies.
1 cm^3 / 2.118069558x10^22 = 4.721280262x10^-23 cm^3
Let's get the cube root to get the length of an edge.
(4.721280262x10^-23 cm^3)^(1/3) = 3.61426x10^-08 cm
Now let's convert from cm to pm.
3.61426x10^-08 cm / 100 cm/m * 1x10^12 pm/m = 361.4 pm
Doing an independent search for the Crystallographic Features of Copper, I see that the Lattice Parameter for copper at at 293 K is 3.6147 x 10^-10 m which is in very close agreement with the calculated amount above. And since metals expand and contract with heat and cold, I assume the slight difference in values is due to the density figure given being determined at a temperature lower than 293 K.</span>
Answer:
When fossil fuels are burned, they release large amounts of carbon dioxide, a greenhouse gas, into the air. Greenhouse gases trap heat in our atmosphere, causing global warming. Already the average global temperature has increased by 1C.
Explanation:
