Sixteen grams of oxygen contain avogadro’s number of atoms, with each atom having eight protons and eight electrons. how many coulombs, q, of positive charge are there in the protons of 1.0kg of oxygen?
(a) 4.8 x 10^7 c
(b) 5.2 x 10^15 c
(c) 5.4 x 10^-5 c
(d) 1.7 x 10^-9 c
(e) 2.0 x 10^6 c

The correct answer is A

Explanation:

The electric charge of a proton is 1,6×10^-19 C. If you have eight protons in each atom, and you have 6.02×10^23 (Avogadro's number) atoms 16 grams of oxygen, in 1 kg you will have:

16 grams 8 protons x 6.02×10^23 = 4,81×10^24 protons

1000 grams (1000 x 4,81×10^24)/16 = 3,01×10^26 protons.

3,01×10^26  protons x 1,6×10^-19C = 4,8×10^7 C

we can conclude that the melting point of table salt is above room temperature (it's actually 801 deg c). the melting point of mercury must be below room temperature (- 39 deg c).