You are given 10.58 grams of substance x. the specific heat of this substance is 3.58 j/g·°c. if the mass of substance x is doubled, the specific heat of this substance will also double

I don't know where the question is, but I will assume that this is a True or False statement.

If that is the case, this statement is false.

You have the equation Q = mcΔT.

The statement states that if m is doubled, c is doubled as well. This is incorrect, since the specific heat value cannot be changed because it is attributed to the specific substance. If m doubles with the same substance, assuming a constant change in temperature, the only thing that can change is Q, which is the heat energy gained or lost from the substance.

Only one reactant yields 2 or more products. meaning you will only have 1 product and it will break down into 2 or more products. eg. h2o -> h2 + o2