Hello!
The number of 20-g ice cubes required to absorb 47 kJ from a glass of water upon melting is 7 icecubes
Why?
We are going to clear from the equation of the released heat, the mass of ice (m). The specific latent heat of fusion of ice is 336 kJ/kg:

So, 7 ice cubes are required to absorb that amount of heat from the glass of water.
Have a nice day!
Answer:
Hey, I hope this helps. You gave the equation already balanced so there was no need to do so, the next thing we need to do after balancing is to split the strong electrolytes into ions. Once that is completed we cross off any reoccurring ions. That leaves us with our complete net ionic.
I also recommend you check out Wayne Breslyn on Yt. He is so helpful with equations like these.
Every electron carries one elementary negative charge. Concerning mass,
it takes roughly 1,840 electrons to make enough mass for 1 proton or 1 neutron.
Electrons don't necessarily have to stay connected to an atom, but when they do,
they circle the nucleus.
So you should select (C): ==> Negative, ==> light, ==> circling the nucleus.