Answer:- Mass of the titanium alloy is 7.01 g, choice C is correct.
Solution:- The heat of fusion is given as 422.5 joules per gram and it also says that 2960 joules of heat is required to melt the metal completely.
The suggested equation is, 
where Q is the heat energy, m is the mass and Hf is the heat of fusion.
Since, we are asked to calculate the mass, the equation could be written as:

Let's plug in the values in it:

m = 7.01 g
So, the mass of the titanium alloy is 7.01 g, choice C is correct.
Nomenclature and common formula. When part of a salt, the formula of the acetate ion is written as CH3CO2−, C2H3O2−, or CH3COO−. Chemists abbreviate acetate as OAc− or, less commonly, AcO−. Thus, HOAc is the abbreviation for acetic acid, NaOAc for sodium acetate, and EtOAc for ethyl acetate.
Answer: concentration
Explanation:
Concentration refers to the amount of a substance present in a sample. The more molecules of a substance present in a sample, the greater its concentration. The less molecules of a substance in a sample, the lesser the concentration. We are often concerned about analytically determining the concentration of a substance using diverse analytical methods in chemistry.