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Topic: Need help with a school science project  (Read 5012 times)

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chemmajor

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Need help with a school science project
« on: April 21, 2005, 08:21:40 PM »
Does anyone know what two chemicals that are easy to acquire and not too expensive to buy ..when combined can create a freezing temperture? ???

Froggirl

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Re:Need help with a school science project
« Reply #1 on: April 21, 2005, 09:31:08 PM »
I'm not sure about getting it to 0oC but there are plenty of salts that when you dissolve them in water its an endothermic reaction (ie reaction occurs with the absorption of heat making the solution feel cold).

For instance dissolving ammonium chloride or ammonium nitrate in water is an endothermic. They're pretty cheap too. They often use them for those cold packs that don't need to be stored in the freezer.  :)

Offline eugenedakin

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Re:Need help with a school science project
« Reply #2 on: April 21, 2005, 09:45:58 PM »
Hello Chemmajor,

There are many mixtures.  In my Merck, here are some endothermic mixtures.

Substance                     Substance  Water          temp.
                                   Quantity     Quantity      change (C)
sodium acetate              85             100              -4.7
sodium nitrate               75             100              -5.3
calcium chloride .6H2O   100           246 (ice)       -9.0
sodium chloride             36             100              -10.0
sodium nitrate               50             100 (ice)       -17.8
sodium chloride             33             100 (ice)        -21.3
calcium chloride .6H2O   100           123 (ice)         -21.5
sodium bromide            66             100 (ice)         -28
magnesium chloride cryst 85           100 (ice)         -34
calcium chloride .6H2O     100         81 (ice)          -40.3
calcium chloride .6H2O     100         70 (ice)          -55


I hope this helps,

Eugene
« Last Edit: April 09, 2007, 04:33:51 PM by eugenedakin »
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chemmajor

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Re:Need help with a school science project
« Reply #3 on: April 24, 2005, 06:36:26 PM »
Thanks you sir!! I will discuss it with my team to see which one will best apply to our use.  :)


Hello Chemmajor,

There are many mixtures.  In my Merck, here are some endothermic mixtures.

Substance                     Substance  Water          temp.
                                   Quantity     Quantity      change (C)
sodium acetate              85             100              -4.7
sodium nitrate               75             100              -5.3
calcium chloride .6H2O   100           246 (ice)       -9.0
sodium chloride             36             100              -10.0
sodium nitrate               50             100 (ice)       -17.8
sodium chloride             33             100 (ice)        -21.3
calcium chloride .6H2O   100           123 (ice)         -21.5
sodium bromide            66             100 (ice)         -28
magnesium chloride cryst 85           100 (ice)         -34
calcium chloride .6H2O     100         81 (ice)          -40.3
calcium chloride .6H2O     100         70 (ice)          -55


I hope this helps,

Eugene Dakin Ph.D., P.Chem.

Garneck

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Re:Need help with a school science project
« Reply #4 on: April 25, 2005, 09:25:37 AM »
I don't know about the prices, but what about some dry ice (solid CO2) and acetone?

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