1) The metal which reduces the other compound is the one higher in the reactivity. So in this case it is .
2) The substance which brings about reduction while itself getting oxidised (that is losing electrons) is called a reducing agent. Here, $\mathrm{Zn}$ is the reducing agent and reduces Cobalt Oxide to Cobalt while itself getting oxidised to Zinc oxide.
Answer: 2800 calories
Explanation:
Latent heat of fusion is the amount of heat required to convert 1 mole of solid to liquid at atmospheric pressure.
Amount of heat required to fuse 1 gram of water = 80 cal
Mass of ice given = 35 gram
Heat required to fuse 1 g of ice at = 80 cal
Thus Heat required to fuse 35 g of ice =
Thus 2800 calories of energy is required to melt 35 g ice cube