Redox reaction in assign oxidation number is ca3(po4)2
You know ALL compounds are zero.
Ca is +2 each. 3*2 = 6+
You know O is -2 each. 8*-2 = -16
Since everything must add to zero, then
+6 +(-16) + 2P = 0
-10 + 2P = 0
2P = 10
P = +5 each
X-RAY DIFFRACTION OF AN UNKNOWN METAL, MIGHT BE DANGEROUS (10/10 points)
Last week you and a friend started an experiment to obtain the X-ray diffraction peaks of an unknown metal. Through these diffraction peaks you wanted to determine:
(a) whether the cell is SC, BCC, or FCC
(b) the (hkl) value of the peaks
(c) the lattice parameter a of the metal
Unfortunately, however, your friend (since he's not in 3.091) left MIT yesterday, not to return until next semester. All of the data that you could recover from the rubble in his room was the following:
[mathjaxinline] sin^2(\theta) [/mathjaxinline] 0.120 0.239 0.480 0.600 0.721 0.841 0.956
You also know that the metal is in the cubic crystal system and the wavelength of the X-rays used is [mathjaxinline] \lambda_{CuK_{\alpha}} [/mathjaxinline]. Using the following information, determine the information you were originally interested in (a, b, and c above).
a. Is the cell SC, BCC, or FCC?
SC<text>SC</text> - correctFCCBCC
b. Enter the hkl value of the peaks as a list separated by commas. Do not put spaces between the values. For instance:
[mathjaxinline] \theta_1,\theta_2,... = (100),(111),... [/mathjaxinline]
(100),(110),(111),(200),(102),(112),(202) - correct
c. Enter the lattice parameter a in Angstroms.
2.24 - correct
To assign oxidation numbers in the compound Ca3(PO4)2, you need to follow a few steps:
Step 1: Identify the individual elements in the compound.
The compound Ca3(PO4)2 consists of the elements calcium (Ca), phosphorus (P), and oxygen (O).
Step 2: Start by assigning the oxidation number for the more electronegative element or the one that occurs in a known compound.
In this case, oxygen is more electronegative and is usually assigned an oxidation number of -2.
Step 3: Determine the oxidation number for the remaining elements based on the known oxidation number for oxygen.
Since there are 4 oxygen atoms in the compound, the total oxidation number contribution is 4 × -2 = -8.
Step 4: Determine the sum of the oxidation numbers for all elements in the compound.
The compound is electrically neutral, so the sum of the oxidation numbers must be zero.
Step 5: Use the sum of oxidation numbers obtained in Step 4 to determine the oxidation numbers for the remaining elements.
In Ca3(PO4)2, there are three calcium atoms. Let's assume the oxidation number of calcium is x. Therefore, the oxidation number contribution from calcium is 3x.
Since oxygen has an oxidation number of -2, the oxidation number contribution from oxygen is -8.
Since the compound is electrically neutral, the sum of the oxidation number contributions from each element must equal zero.
Therefore, (3x) + (-8) = 0.
Simplifying the equation: 3x - 8 = 0.
Step 6: Solve the equation for the unknown variable (x), which represents the oxidation number for calcium.
3x = 8.
Divide both sides of the equation by 3:
x = 8/3.
Therefore, the oxidation number for calcium (Ca) in the compound Ca3(PO4)2 is +8/3 or approximately +2.67.
To assign oxidation numbers in a compound, you need to follow a few rules:
1. The oxidation number of an element in its elemental state is always zero. This means that each Ca atom in Ca3(PO4)2 will have an oxidation number of 0.
2. The overall charge of the compound must be zero. In this case, since there are no charges indicated, the overall charge is zero. So the sum of the oxidation numbers of all the atoms in the compound must be zero.
3. The oxidation number of Group 1A elements (such as Ca) is always +1, and for Group 2A elements (such as Ca), like in this case, it is always +2.
Now let's assign oxidation numbers to the remaining elements in the compound:
- Oxygen (O) almost always has an oxidation number of -2, except in peroxides (such as H2O2), where it is -1.
- Phosphorus (P) doesn't have a fixed oxidation number, so we need to calculate it. Considering that each oxygen atom has an oxidation number of -2, and there are 4 oxygen atoms bound to each P atom, we have a total oxidation number of -8 for the oxygen atoms around each P atom.
- Since the overall compound has a charge of zero, the sum of all the oxidation numbers must be zero. We have three Ca atoms, each with an oxidation number of +2, so the total oxidation number contributed by the Ca atoms is +6.
- Let's assume the oxidation number of each P atom is x. Since there are 2 P atoms, the total oxidation number contributed by the P atoms is 2x.
- Therefore, the equation becomes: +6 + 2x - 8 = 0.
Simplifying the equation, we get: 2x - 2 = 0, which leads to x = +1.
Hence, the oxidation number for Ca is +2, for P is +1, and for O is -2 in the compound Ca3(PO4)2.