How many kilograms of nickel must be added to 1.75 kg of copper to yield a liquidus temperature of 1300°c?

Mass of Ni = 1.32 kg

Based on the Cu-Ni phase diagram, the %composition of Ni at a liquidus temperature of 1300 C is around 43 wt%

Now,

wt% Ni = [mass of Ni/mass of Ni + mass of Cu]*100

if x is the mass of Ni required then:

wt%Ni/100 = x/x+1.75

0.43 = x/x+1,75

0.43x + 0.75 = x

x= 1.316 kg

answer: c. the experiment shows that the red substance experienced a chemical change.

explanation: chemical change is the change in which chemical composition of the substance changes. physical change is the change in which there is no change in chemical composition.

chemical changes are accompanied by following changes:

a) precipitate formation

b) energy is released or absorbed

c) formation of bubbles

d) change in color

as it is given that the red color has disappeared and there is production of gas, it means the red substance has undergone a chemical change.

e