I like to put ice (c= 2.11 J/gC) in my coffee to cool it down. If the temperature of the ice I get out of my refrigerator is at 2°C and drop it into 100g of hot coffee at 80°C (c = 4.18 J/g°C).
How much ice would I need to use if I want the ending temperature to be 50°C?
*make sure to include the units on your answer

nacl is added to the aqueous of what? ? in order to get a proper answer you have to specify the exact composition of the aqueous solution.

"among the transition metal elements, manganese and zinc have a slight lowering of electronegativities. the reason behind this is that the nuclear charges of these elements are slightly weaker than the other transition metal elements due to the way their valence electrons are filled up. both manganese and zinc have their valence electrons filled up to the 4th shell with 1 pair of electrons (4s2) completely occupying it. although the electrons in the 3rd shell (3d) are yet to be paired since the outer most shell is filled up, the ability of the nucleus to attract electrons is lessened. hence,   the electronegativity (or the ability to attract electrons) is lessened."

the answer is 303.15 or 303