E: 29/11 Win six mind-boggling science books in time for Christmas – competition

JamboDP

I would say that No4 is stays the same temperature, all it does is make the water freeze at a lower temp, it does not change the temp
I think we could do with the prize to work out the answers.

BlueBella

I am bamboozled now lol!

Geeky

I believe that the solution of table salt (sodium chloride) in water is slightly endothermic, so the water gets cooler

http://www.chem.ox.ac.uk/vrchemistry/energy/Page_26.htm

However if you add salt to ice, this cooling effect is masked by the drop in the temperature at which the water freezes, so although the water is (temporarily) slightly cooler, it will stay liquid at temperatures when untreated water will freeze.

BlueBella

Geeky wrote: »

I believe that the solution of table salt (sodium chloride) in water is slightly endothermic, so the water gets cooler

http://www.chem.ox.ac.uk/vrchemistry/energy/Page_26.htm

However if you add salt to ice, this cooling effect is masked by the drop in the temperature at which the water freezes, so although the water is (temporarily) slightly cooler, it will stay liquid at temperatures when untreated water will freeze.

so are we going for 'the water gets colder?

Mammy_of_4_boys

Yeah...I went with 'The water gets colder'.

BlueBella

OMG Seriously - I have the Monday Morning Blond Bimbo Blues today! I am all over the place - thanks for the help guys! At least there are some 'MSE on the ballers' today!!!

koala_mick

3 is organic x

hamster

BlueBella wrote: »

so are we going for 'the water gets colder?

Looks like it's confirmed by another source here:

http://antoine.frostburg.edu/chem/senese/101/solutions/faq/why-salt-cools-icewater.shtml

[FONT=geneva,Helvetica,Arial,sans-serif][SIZE=-1][FONT=geneva,Helvetica,Arial,sans-serif][SIZE=-1]Does adding salt to ice and water cause a temperature drop? Yes. This is how old-fashioned ice cream makers lowered the temperature of the ice cream below water's ordinary freezing point. A mixture of rock salt, ice, and water packed in the bucket around the ice cream mix can bring the temperature down as low as -21°C. [/SIZE][/FONT][/SIZE][/FONT]

One-Eye

Food that doesn't contain any chemicals
a) is known as organic
b) was grown without pesticides
c) will help you lose weight
d) is much healthier

I'm not happy with any of these.
a) Organic food is 100% chemicals. (Organic Milk = water, lipids, calcium, sugars, vitamins etc. - all chemicals)
b) Food grown without pesticides is also 100% chemicals.
d) many, many, chemicals are essential for life and health

which leaves c) food with no chemicals is an absence of food - which will help you lose weight.

xangeleyes

I think the ice gets colder.

Reasons - watch ice and salt challenge.
We've done it (Stupidly) and it was so cold it was painful!
It can freeze the skin it's on.