Why is the liquid oxygen machine producing less liquid oxygen than normal?
State your claim and use evidence to support
it. For each piece of evidence you use, explain
how the evidence supports your claim or
refutes another claim. Remember to explain
what happened at both the macro and
molecular scale.

Claim 1: there is frozen water in tank 2, which is blocking some of the oxygen from going into tank 3
Claim 2: some of the liquid oxygen evaporated in tank 3.
Claim 3: some of the oxygen didn’t condense in tank 2

substituting a hydrogen atom with a halogen in a hydrocarbon:

- the single bond remains single. a is wrong.

- the bond with hydrogen is as strong as with a halogen. c is wrong

- a hydrocarbon is saturated if there is no double bond. we do not know that so d is wrong.

- carbon will always have four valence electrons. e is wrong.

by elimination, the correct answer is b. the boiling point of the new compound increases.

answer is: nuclear fusion produces elements that are heavier than helium.

nuclei combine to form a heavier nucleus, releasing energy.  

for example, fusion of hydrogen atoms at the sun.  

this fusion nuclear reaction is in the inner core of the sun and hydrogen (atomic number 1) is conveted into helium (atomic number 2).  

the inner core is the central region of the sun and all solar energy is produced in the core by nuclear fusion.