chemistry essay

Topics: Temperature, Calcium carbonate, Calcium oxide Pages: 5 (767 words) Published: June 4, 2014
QUEST0ION 1 - EXAMPLES OF DIFFERENT SELF-HEATING FOOD AND DRINK YOU COULD BUY:

SOURCE 1: http://www.hotboxfood.co.uk/content/11-drinks-soups

DATE ACCESSED: 04/02/14

Hotbox Food would like to present a line of delicious beverages in completely self-heating cans. Thanks to these innovative containers called "Hotshots", it is now possible to drink high quality beverages at any time and at any place. Neither an external heat source, nor any other cooking utensils are required. Drinks 2go recipes do not contain additives, preservatives, artificial colourings or any raw materials obtained from GMO (Genetically Modified Organisms).

Now you can enjoy a Hot Drink or a Hot Tin of Soup in 3 Minutes wherever you may be. These products are perfect for the Camper, the Rambler, the Fisherman, the Sales Person who does not want to get caught short when stuck on the Motorway or indeed anyone who likes the convenience that our Hotshots Drinks and Soups offer.

SOURCE 2: http://evaq8.co.uk/Self-Heating-Food.html

DATE ACCESSED: 04/02/14

Self-Heating Meal in a Bag All Day Breakfast

Self-Heating Meal in a Bag Beans & Potato

Self-Heating Meal in a Bag Chicken & Potato Curry

Self-Heating Meal in a Bag Chicken Curry With Rice

Self-Heating Meal in a Bag Meatballs with Pasta

Self-Heating Meal in a Bag Thai Green Chicken Curry

Self-Heating Meal in a Bag Thai Green Vegetable Curry

Self-Heating Hot Drink Black Coffee

Self-Heating Hot Drink Cappuccino

Hot Can Self Heating Meal Cheese Ravioli Vegetarian

HotCan Self Heating Meal Meatballs With Beans

HotCan Self Heating Meal Tortellini Bolognaise

SOURCE 3: http://evaq8.co.uk/Self-Heating-Food.html

QUESTION 2 - WHAT CHEMICALS ARE USED TO HEAT UP FOOD AND DRINK IN THESE CANS?:

Heat is generated inside the Hot-Can from the mixing of Calcium Oxide (quicklime, CaO) with Hydrogen Dioxide (water, H2O) which produces Calcium Hydroxide (Ca(OH)2)

The formula for this exothermic reaction is:

CaO + H2O > Ca(OH)2 + Heat

Once the heating reaction is complete, the Calcium Hydroxide (Ca(OH)2) reacts readily with Carbon Dioxide (CO2 ) in the air to form Calcium Carbonate (limestone, Ca CO3) and returns to its original state

The formula for this reaction is:

Ca(OH)2 + CO2 > Ca CO3 + H2O

he reactions are essentially CO2 neutral: Carbon dioxide (CO2) is released in producing the Calcium Oxide (quicklime, CaO ) by heating Calcium Carbonate (limestone, Ca CO3) to extremely high temperatures, and is subsequently reabsorbed during the reaction.

What makes it heat up?

Hot-Can has developed a special double chambered aluminum can which contains the beverage in the outer chamber and holds water and calcium oxide (quick lime) separately in the inner chamber. When the button at the bottom of the can is pressed, the water mixes with the quicklime, starting an exothermic reaction that heats the contents of the outer chamber in less the 3 minutes by 50-55°C to give you a piping hot drink.

SOURCE 4: http://www.hot-can.com/Australia/howto.html

QUESTION 3 - WHAT TYPE OF REACTION TAKES PLACE BETWEEN THESE CHEMICALS?

EXOTHERMIC REACTIONS

When a chemical reaction occurs, energy is transferred to or from the surroundings - and there is often a temperature change.

Exothermic reactions transfer energy to the surroundings. The energy is usually transferred as heat energy, causing the reaction mixture and its surroundings to become hotter. The temperature increase can be detected using a thermometer.

Source 7: http://www.bbc.co.uk/schools/gcsebitesize/science/add_aqa/exothermic/exothermic_endothermicrev1.shtml

During a chemical reaction:

Bonds in the reactants are broken

New bonds are made in the products

Energy is absorbed to break bonds. Bond-breaking is an endothermic process.

Energy is released when new bonds form. Bond-making is an exothermicprocess.

Whether a reaction is endothermic or exothermic depends on the...

Bibliography: :
SOURCE 1: http://www.hotboxfood.co.uk/content/11-drinks-soups
SOURCE 2: http://evaq8.co.uk/Self-Heating-Food.html
SOURCE 3: http://evaq8.co.uk/Self-Heating-Food.html
SOURCE 4 : http://www.hot-can.com/Australia/howto.html
Source 5: http://www.gizmag.com/hot-can-self-heating-beverages/25646/
Source 6: http://en.wikipedia.org/wiki/Self-heating_food_packaging#Heating_methods
Source 7: http://www.bbc.co.uk/schools/gcsebitesize/science/add_aqa/exothermic/exothermic_endothermicrev1.shtml
Source 8: http://www.bbc.co.uk/schools/gcsebitesize/science/add_edexcel/chemical_reactions/energychangesrev2.shtml
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