Answer: 
Explanation:
The unbalanced equation is

Balancing this equation, we get:

Answer:
a. fluorine
Explanation:
Fluorine is the element of group 17 and period 2. The electronic configuration of the element is
.
Stable oxidation state = -1 of fluorine as it gains one electron to gain noble gas configuration.
With alkali metals, which have oxidation state of +1 form ionic compound of the form, MX where X is F.
Among the halogens, fluorine forms the most stable halide because of the comparable size of the hydrogen and fluorine. Thus, it is the weakest acid when compared with other hydrogen halides.
Fluorine is the most reactive in the halogen series and thus, combines with most of the elements.
Fluorine forms inter-halogen compounds of form XA only. Example - ClF.
Hence, option a is correct.
Answer:- Density is 10.5 grams per mL and the substance is Silver(Ag).
Solution:- Mass of jewelry is given as 132.6 g. Initial volume of water in the graduated cylinder is 48.6 mL and the volume becomes 61.2 mL when this jewelry is submerged in the cylinder.
So, the volume of the jewelry = 61.2 mL - 48.6mL = 12.6 mL
We know that, 
Let's plug in the values in the above formula to calculate the density:


So, the density of the jewelry is
.
The substance from which the jewelry is made could easily be identified by comparing the calculated density with the density values given for different substances in the density table.
Looking at the density table, 10.5 grams per mL is the density for silver. So, the jewelry is made up from Silver.
Answer:
ΔHrxn = [(1) -1675.5 ( kJ/mole) + (2) 0 ( kJ/mole)] - [(1) -824.3 ( kJ/mole) + (2) 0 ( kJ/mole)]
Explanation:
ΔHrxn = 2ΔHf (Al₂O₃) - ΔHf (Fe₂O₃)
Remember that for pure elements in their standard state of temperature and pressure by definition their standard heats of formation are zero.
ΔHrxn = 2(-1675.7) - (-824.3) kJ/mol
ΔHrxn = 2527 kJ/mol