Question

Oil floats on the surface of water but mercury sinks. Explain why?

Answer 1

Answer:

Because mercury has a molecular weight about 20 times that of water and thus water will float on mercury every time.

H2O molecular weight 18.02 g/mol

Mercury molecular weight 200.59 g/mol

Molecular weight of oil varies but average is 0.071 g/mol

Answer 2

ʙᴇᴄᴀᴜꜱᴇ ᴍᴇʀᴄᴜʀʏ ʜᴀꜱ ᴀ ᴍᴏʟᴇᴄᴜʟᴀʀ ᴡᴇɪɢʜᴛ ᴀʙᴏᴜᴛ 20 ᴛɪᴍᴇꜱ ᴛʜᴀᴛ ᴏꜰ ᴡᴀᴛᴇʀ ᴀɴᴅ ᴛʜᴜꜱ ᴡᴀᴛᴇʀ ᴡɪʟʟ ꜰʟᴏᴀᴛ ᴏɴ ᴍᴇʀᴄᴜʀʏ ᴇᴠᴇʀʏ ᴛɪᴍᴇ.ʜ2ᴏ ᴍᴏʟᴇᴄᴜʟᴀʀ ᴡᴇɪɢʜᴛ 18.02 ɢ/ᴍᴏʟ

ᴍᴇʀᴄᴜʀʏ ᴍᴏʟᴇᴄᴜʟᴀʀ ᴡᴇɪɢʜᴛ 200.59 ɢ/ᴍᴏʟ

ᴍᴏʟᴇᴄᴜʟᴀʀ ᴡᴇɪɢʜᴛ ᴏꜰ ᴏɪʟ ᴠᴀʀɪᴇꜱ ʙᴜᴛ ᴀᴠᴇʀᴀɢᴇ ɪꜱ 0.071 ɢ/ᴍᴏʟ