B (Salters) F331 (Chemistry for Life) 22nd May 2015 [Official Thread]

Watch
vuvuzela
Badges: 3
Rep:
?
#1
Report Thread starter 5 years ago
#1
As per title.
0
reply
SSD07
Badges: 3
Rep:
?
#2
Report 5 years ago
#2
can someone explain geological and archaeological dating please? like in a lot of depth so i have full detail in case a question comes up. Thanks
0
reply
MuslimaSheikh
Badges: 1
Rep:
?
#3
Report 5 years ago
#3
All you have to know for our specification is that in radiocarbon dating, carbon 14 is used to measure how old an object is. The theory behind this is that when plants photosynthesise, they take in a small amount of carbon 14, therefore when animals eat these plants, they also gain a small amount of carbon 14, this amount of carbon 14 is then let back out into the atmosphere (due to aerobic respiration), therefore all living materials are constantly replenishing the amount of carbon 14 inside of them to match the value in the atmosphere. Therefore when an organism dies, this carbon 14 inside of them decays and we can thus measure how old the organism is: the less the amount of carbon 14, the more old it is. This is because we know the half life of carbon 14 and the half life is constant for that given isotope.

However, there are flaws in this, for example how do we know that the decay was constant, there could've been environmental changes which affected the decay and the amount of carbon 14.

Hope this helps ^_^


Posted from TSR Mobile
0
reply
vuvuzela
Badges: 3
Rep:
?
#4
Report Thread starter 5 years ago
#4
(Original post by MuslimaSheikh)
All you have to know for our specification is that in radiocarbon dating, carbon 14 is used to measure how old an object is. The theory behind this is that when plants photosynthesise, they take in a small amount of carbon 14, therefore when animals eat these plants, they also gain a small amount of carbon 14, this amount of carbon 14 is then let back out into the atmosphere (due to aerobic respiration), therefore all living materials are constantly replenishing the amount of carbon 14 inside of them to match the value in the atmosphere. Therefore when an organism dies, this carbon 14 inside of them decays and we can thus measure how old the organism is: the less the amount of carbon 14, the more old it is. This is because we know the half life of carbon 14 and the half life is constant for that given isotope.

However, there are flaws in this, for example how do we know that the decay was constant, there could've been environmental changes which affected the decay and the amount of carbon 14.

Hope this helps ^_^


Posted from TSR Mobile

Yeah the flaws are stuff like;

Parent/daughter isotope could me removed/added, therefore not same age as organism.
The half life may not be constant
If the half life is large, and far exceeds the age of the specimen, then the change in count rate will be small and difficult to detect.
Count caused by other isotopes.
Pretty much what the above poster said.
0
reply
barbiex
Badges: 2
Rep:
?
#5
Report 5 years ago
#5
How about archaeological dating? could someone please explain that in depth too
0
reply
MuslimaSheikh
Badges: 1
Rep:
?
#6
Report 5 years ago
#6
The same concept applies for archaeological dating


Posted from TSR Mobile
0
reply
NapkinofDestiny
Badges: 1
Rep:
?
#7
Report 5 years ago
#7
Could anyone state some of the Molar Calculation formulae we need for this exam?

Im not inept at maths but lets just say its not my cup of tea, I cant seem to get my head around it at all :thumbdown:

Thankyou
0
reply
Meloddymaybe
Badges: 1
Rep:
?
#8
Report 5 years ago
#8
(Original post by NapkinofDestiny)
Could anyone state some of the Molar Calculation formulae we need for this exam?

Im not inept at maths but lets just say its not my cup of tea, I cant seem to get my head around it at all :thumbdown:

Thankyou
The 2 we need to know are:

1. moles = concentration (in moles per dm^3) times volume (in dm^3)

2. moles = mass (in grams) divided by formula mass

(:
0
reply
NapkinofDestiny
Badges: 1
Rep:
?
#9
Report 5 years ago
#9
(Original post by Meloddymaybe)
The 2 we need to know are:

1. moles = concentration (in moles per dm^3) times volume (in dm^3)

2. moles = mass (in grams) divided by formula mass

(:
Thankyou )
0
reply
GianluigiBuffon
Badges: 3
Rep:
?
#10
Report 5 years ago
#10
Resitting this exam cause i got a D last year, I'm so **** at chemistry :/
0
reply
Marli-Ruth
Badges: 2
Rep:
?
#11
Report 5 years ago
#11
How did everyone do on F333 Skills test
0
reply
GianluigiBuffon
Badges: 3
Rep:
?
#12
Report 5 years ago
#12
(Original post by Marli-Ruth)
How did everyone do on F333 Skills test
I got an A on it last year (85%)
0
reply
vuvuzela
Badges: 3
Rep:
?
#13
Report Thread starter 5 years ago
#13
(Original post by Marli-Ruth)
How did everyone do on F333 Skills test
Everyone should be done for F333 next year we should help each other out. Some people do skills before and after others so a few pointers could be given if you know what I mean
0
reply
Marli-Ruth
Badges: 2
Rep:
?
#14
Report 5 years ago
#14
(Original post by GianluigiBuffon)
I got an A on it last year (85%)
An A was 53/60?
According to the grade boundaries so you got 88%? No?

That's really good! I got just on the A boundary so I'm chuffed!
0
reply
GianluigiBuffon
Badges: 3
Rep:
?
#15
Report 5 years ago
#15
(Original post by Marli-Ruth)
An A was 53/60?
According to the grade boundaries so you got 88%? No?

That's really good! I got just on the A boundary so I'm chuffed!
I got 51/60 UMS which is 85% and around 55/60 raw marks and thats really good!!! keep up the good work
0
reply
Tajwar786
Badges: 2
Rep:
?
#16
Report 5 years ago
#16
The light and electron chapter is really confusing like, I know how to describe how absorption and emmision spectra looks like (colour line on black bg or black lines on colour bg) when passes through a prism, but what is the idea behind this??? Why do we use prism or what this lines actually means and why the gaps of lines get smaller at higher frequncy. Thanks in advance
0
reply
GianluigiBuffon
Badges: 3
Rep:
?
#17
Report 5 years ago
#17
(Original post by Tajwar786)
The light and electron chapter is really confusing like, I know how to describe how absorption and emmision spectra looks like (colour line on black bg or black lines on colour bg) when passes through a prism, but what is the idea behind this??? Why do we use prism or what this lines actually means and why the gaps of lines get smaller at higher frequncy. Thanks in advance
Basically electrons absorb a certain wavelength of light which corresponds to a particular colour and at a specific frequency. So this is why we get the lines innit
0
reply
vuvuzela
Badges: 3
Rep:
?
#18
Report Thread starter 5 years ago
#18
(Original post by Tajwar786)
The light and electron chapter is really confusing like, I know how to describe how absorption and emmision spectra looks like (colour line on black bg or black lines on colour bg) when passes through a prism, but what is the idea behind this??? Why do we use prism or what this lines actually means and why the gaps of lines get smaller at higher frequncy. Thanks in advance
E=hf
Energy proportional to frequency
Emission spectra is black background coloured lines
Absorption is coloured background black lines

Both have lines which get closer at higher frequencies


Posted from TSR Mobile
0
reply
tealover96
Badges: 15
Rep:
?
#19
Report 5 years ago
#19
Also re-sitting this exam and feel like I'm ready
Paper last year was meaner then usual so hopefully they feel like being nicer this year
Then again this is salters
0
reply
Bruhh
Badges: 10
Rep:
?
#20
Report 5 years ago
#20
Feeling fairly good about this, I think its a much nicer paper than Natural Resources by far.
1
reply
X

Quick Reply

Attached files
Write a reply...
Reply
new posts
Back
to top
Latest
My Feed

See more of what you like on
The Student Room

You can personalise what you see on TSR. Tell us a little about yourself to get started.

Personalise

If you do not get the A-level grades you want this summer, what is your likely next step?

Take autumn exams (207)
46.94%
Take exams next summer (63)
14.29%
Change uni choice through clearing (100)
22.68%
Apply to uni next year instead (45)
10.2%
I'm not applying to university (26)
5.9%

Watched Threads

View All