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제목 [Roy Lee] properties of water (EMERGENCY!!!!)
ibh bio 2.2 water 13
작성자 suk*** 등록일 2019-10-08 오후 8:43:01

쌤 저 정말 급합니다ㅠㅠ

2.2 water sample problem 1번에서 causes of high boiling point가 because of hydrogen bonds within water molecules때문이고, 

water랑 oxygen의 결합은 hydrogen bonds가 아닌 covalent bond라고 했잔아요.

근데 kognity에서 causes of high specific heat 가 hydrogen bonds between water and oxygen이라네요.... 아래는 그 문제 explanation copy and paste 한거에요.. 

어떤게 정답이고 hydrogen bonds definition좀 확실히 알려주세요..ㅠ 헷갈리게 됬어요

What causes water to have a relatively high specific heat capacity?

#1

Covalent bonds between hydrogen and oxygen within water molecules.

#2

Cohesion between water molecules and the container in which the water is boiled.

#3

Hydrogen bonds between hydrogen and oxygen of different water molecules.

#4

Hydrogen bonds within water molecules.

Explanation

Not #4: This is not true as the bonds within water molecules are covalent bonds. Not #2: the boiling point is a property of water itself; cohesion between the water molecules due to the intermolecular hydrogen bonds between the H atoms and the O atoms of different water molecules cause this. Not #1: Covalent bonds between hydrogen and oxygen within water molecules are not broken down when water boils. Therefore, option #3 is the correct answer.
2019-10-09 오후 1:13:20

안녕하세요!

 

아니에요! 학생이 말한 부분 다시 한번 잘 확인해보세요!

강의 1번 문제에서 the causes of high boiling point 답은 because of hydrogen bond "BETWEEN" water molecules이죠?

학생이 말한 "WITHIN" water molecules랑 전혀 다른 거에요!

 

처음 chemistry 내용 정리하면서 intramolecular / intermolecular bonds의 차이를 구분했던거 기억나죠?

그때 ionic, covalent bonds는 intramolecular bonds 이고 (예를 들면, covalent bond between H and O within water molecules)

hydrogen bonds는 intermolecular bonds 라고 했어요. (예를 들면, hydrogen bonds between water molecules)

 

그렇기 때문에 c)가 정확히 맞는 말이죠. hydrogen bonds between different water molecules이고,

조금 더 구체적으로 말하자면, that hydrogen bond forms because of slight polarity between hydrogens and oxygens of the water molecules 이에요.

 

d)의 경우 hydrogen bonds cannot exist within water molecules, so it cannot be the right answer.

only covalent bonds exist "within" water molecules.

hydrogen bonds exist "between" water molecules.

 

차이가 이해 됐나요?

해당 단원에서 hydrogen bond 관련된 내용 다시 한번만 천천히 복습해보면 좋을것 같아요.

열공 하시고 혹시 또 질문 생기면 게시판에서 만나요! :D

 

 
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