The answer should be D. A rate law needs to be rate equaling the rate constant which is represented as k (make sure you use a lower case k since an upper case K is for equilibrium) times the concentrations of each reactant raised to the power of what ever order it has. (if A was a zero order it would be [A]⁰ and if A was third order it would be [A]³).
Do not get the order the reactants are confused with the coefficients in the chemical equation. (just because the reaction has 2B does not mean the rate law will have [B]². As shown in this example since it is first order therefore being [B] in the rate law)
I hope this helps. Let me know if anything is unclear in the comments.
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.
The burning of fossil fuels like coal, natural gas etc... leads to the emmission of carbondioxide which is a green house gas and leads to the increase of heat in the atmosphere. This results in greenhouse effect.
N2 + 3H2 --> 2NH3
When 100g of N2 , no of moles of N2= 100/(28)=3.57 mol
no. of moles of h2 = 6/(2)=3mol
Therefore h2 is limiting reagent.
no. of moles of ammonia= 3/3*2=2moles
mass of ammonia produced= 2 mol * (14+3)= 34g
Answer:
A force involves an interaction between two or more objects, and it causes a push or pull between the objects. ... Good examples of opposing force include drag due to interaction with an air mass and the force due to friction between two objects.