• Congratulations to the Class of 2024 on your results!
    Let us know how you went here
    Got a question about your uni preferences? Ask us here

A DILEMMA! involving the masses of neutron in kg and in amu (1 Viewer)

kooltrainer

New Member
Joined
Jun 17, 2006
Messages
659
Gender
Male
HSC
2008
well
1 amu = 1.661x10^-27 kg
but 1 neutron = 1.675x10^-27

so it should have 1.008428657 amu

BUT IN TEXTBOOKS (QUITE A FEW) IT FRIGGEN SAYS 1.008665 amu
WTF!?!
this problematic coz i need to no how to convert in order to answer those mass defects questions ...

sum1 plz explain
 

Graceofgod

Member
Joined
Feb 17, 2008
Messages
136
Location
Now? A computer.
Gender
Undisclosed
HSC
2008
kooltrainer said:
well
1 amu = 1.661x10^-27 kg
but 1 neutron = 1.675x10^-27

so it should have 1.008428657 amu

BUT IN TEXTBOOKS (QUITE A FEW) IT FRIGGEN SAYS 1.008665 amu
WTF!?!
this problematic coz i need to no how to convert in order to answer those mass defects questions ...

sum1 plz explain
Although I can't be bothered to explore this, working backwards from the textbook value you get a mass for the neutron of approximately 1.6754
It is possible the textbooks have simply used a more accurate value for the mass of a neutron.

EDIT: It seems the mass of neutron is actually closer to 1.6749, well, I'm stumped :)

Ah no i got it. 1 amu ≈ 1.6605402x10^-27 kg Try this value.
 
Last edited:

a-n-d-r-e-w

Member
Joined
Mar 24, 2008
Messages
55
Gender
Male
HSC
2008
Im not sure, just use whatever values they give you on your formula sheet. And if it is really killing you then ring the hsc advice line, but if u do that please post up their answer to it
 

kooltrainer

New Member
Joined
Jun 17, 2006
Messages
659
Gender
Male
HSC
2008
a-n-d-r-e-w said:
Im not sure, just use whatever values they give you on your formula sheet. And if it is really killing you then ring the hsc advice line, but if u do that please post up their answer to it
yeh, all they have on the formula sheet is the mass of neutro/proton/electron in terms of kgs ... when u tried to find it in terms of amu. . . it wont be 1.008665 (Which is the correct value) .. .

=/ . . . and so.. if they dun give u the mass of neutron in amu in the exam ... then... i dunno how we're gona calculate mass defect
 

helper

Active Member
Joined
Oct 8, 2003
Messages
1,183
Gender
Male
HSC
N/A
If you use the data sheet value and the conversion factor from the data sheet, then youwill be marked correctly, if all other working is correct. They will normally supply values in AMUs, if they want you to do it that way.

Otherwise, you can convert any AMU data to kgs and work in the same way.
 

Users Who Are Viewing This Thread (Users: 0, Guests: 1)

Top