You are Here: Home

# mixing ratio

Announcements Posted on
Uni student? You could win a Samsung Galaxy S7 or £500 of travel vouchers by taking this quick survey 05-05-2016
Talking about ISA/EMPA specifics is against our guidelines - read more here 28-04-2016
1. Hi,
how would I go about working this problem out:

3 units of water that are 5oC mix with 2 units of water that are 10oC, what is the resultant temperature of the mixture?

thanks
2. (Original post by mchammer)
Hi,
how would I go about working this problem out:

3 units of water that are 5oC mix with 2 units of water that are 10oC, what is the resultant temperature of the mixture?

thanks
(3 x 5) + (2 x 10) = 15 + 20 = 35, so 35 is the 'total temperature'

There are 5 units, so for the mean temperature, you do 35/5 = 7oc.
3. (Original post by thegodofgod)
(3 x 5) + (2 x 10) = 15 + 20 = 35, so 35 is the 'total temperature'

There are 5 units, so for the mean temperature, you do 35/5 = 7oc.
That would be incorrect.

(Original post by mchammer)
Hi,
how would I go about working this problem out:

3 units of water that are 5oC mix with 2 units of water that are 10oC, what is the resultant temperature of the mixture?

thanks
I'm assuming the specific heat capacity of water = 4.2 J/g degC

The temperature of the 3 unit setup is higher than that of the 2 unit setup. Hence, when mixed together, thermal energy will flow from the 3 units to the 2 units until both are at equal temperatures.

3*4.2*(50-T) = 2*4.2*(T-10)

T = final temperature.
4. I would probably use kelvin for this. I'm not sure if it makes a difference, but 50°C is not 5 times as hot as 10°C and therefore doesn't contribute 5x the energy.
5. (Original post by Repressor)
I would probably use kelvin for this. I'm not sure if it makes a difference, but 50°C is not 5 times as hot as 10°C and therefore doesn't contribute 5x the energy.
It wouldn't make a difference since a change in temp. of 1 K = a change of temp. of 1 deg C

## Register

Thanks for posting! You just need to create an account in order to submit the post
1. this can't be left blank
2. this can't be left blank
3. this can't be left blank

6 characters or longer with both numbers and letters is safer

4. this can't be left empty
1. Oops, you need to agree to our Ts&Cs to register

Updated: May 27, 2012
TSR Support Team

We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

This forum is supported by:
Today on TSR

Don't be late