To be able to answer this, you need to have a phase diagram of Cu-Ni alloy. Create a vertical line along 40% in the x-axis. Then, create a horizontal line along the temperature at 1,300°C. The intersection lies outside of the α-L boundary.
<em>Therefore, the system consist solely of the L-phase: 100% L.</em>
The periodic trend of reactivity depends on whether the elements are metals or nonmetals. For metals, reactivity increases down a group and from right to left across a period. Nonmetals do the opposite. For nonmetals, reactivity increases up a group and from left to right across a period. Therefore, the rank is as follows:
Fluorine
Selenium
Neon
Hope this answers the question. Have a nice day.
Elements are pure substances. Carbon is the only one that is pure.
