Does mass affect rate of reaction?
$1$)
Let's admit first that the reaction rate is proportional to the amount of reactants, in the usual way. Whatever the order $1$ or $2$ of the reaction, the rate constant ${k_{1} }$ or ${k_2}$ will not change if the amount of reactant is increased. But the rate of reaction ${r = - dn/dt}$ does increase when the amount of reactant ${n}$ increases, whatever the order.
For $1$st order, the rate is : ${r = - dn/dt = k_1 n}$. So the rate ${r}$ increases by increasing the amount of reactant ${n}$.
For $2$nd order, the rate of rection is : ${r = - dn/dt = k_2 n^2}$. Here too, the rate of reaction increases when the amount of reactant $n$ increases.
$2)$ As the reactant is a solid, the reaction rate may not be proportional to the amount of reactant (in mole). Let's suppose that it is proportional to the surface of the grains. Even so, the surface increases by increasing the amount of powder. As a consequence, the reaction rate does also increase.