# Chemistry I

posted by .

Instant cold packs, often used to ice athletic injuries on the field, contain ammonium nitrate and water separated by a thin plastic divider. When the divider is broken, the ammonium nitrate dissolves according to the following endothermic reaction:

In order to measure the enthalpy change for this reaction, 1.25 of is dissolved in enough water to make 25.0 of solution. The initial temperature is 25.8 and the final temperature (after the solid dissolves) is 21.9 .
Calculate the change in enthalpy for the reaction. (Use as the density of the solution and as the specific heat capacity.)

• Chemistry I -

1.25 what?
25.0 what?
25.8 what?
21.9 what?
Also the sentence in parentheses omits the density and specific heat of water to be used.
The following is how the problem is solved after you plug in the right units.
q = mass H2O x specific heat H2O x delta T
q/grams = delta H/gram and
(delta H in J/g) x molar mass NH4NO3 = delta H in J/mol.

## Similar Questions

1. ### Chemistry

Instant cold packs used to treat athletic injuries contain solid NH4NO3 and a pouch of water. When the pack is squeezed, the pouch breaks and the solid dissolves, lowering the temperature because of the following endothermic reaction. …
2. ### chemistry

ammonium nitrate decomposes to N2O and water at temperatures between 250 C and 300 C. Write a balanced chemical reaction describing the decomposition of ammonium nitrate, and calculate the standard heat of reaction using the appropriate …
3. ### chemistry

if u had used 40ml of water and 6g of ammonium nitrate ,rather than 20ml water n 3g ammonium nitrate. would u expect to get a larger,smaller or identical temp. change?
4. ### chemistry

Instant cold packs, often used to ice athletic injuries on the field, contain ammonium nitrate and water separated by a thin plastic divider. When the divider is broken, the ammonium nitrate dissolves according to the following endothermic …
5. ### Chemistry 1150

Instant cold packs, often used to ice athletic injuries on the field, contain ammonium nitrate and water separated by a thin plastic divider. When the divider is broken, the ammonium nitrate dissolves according to the following endothermic …
6. ### chemistry

Ammonium nitrate is used in explosives and is produced from the reaction of ammonia and nitric acid. If 15 kg of ammonia give an actual yield of 65.3 kg of ammonium nitrate, what is the percent yield?
7. ### Chemistry

How many moles of ammonium nitrate is created from 10.7 grams of ammonium nitrate?
8. ### Scienc

The dissolution of ammonium nitrate in water changes the temperature of water from 21C to - 1C(ice). If the molar enthalpy of ammonium nitrate is 25.7kj/mol. Determine the mass of ammonium nitrate that was dissolved
9. ### Chemistry

A cold pack manufacturer has decided to change the chemical in their cold pack from ammonium nitrate to ammonium chloride, a safer chemical. The original cold pack formulation used 100.0g of room temperature (27.0C) water and 35 g …
10. ### Chemistry

Ammonium nitrate a common fertilizer was used by terrorists in the trgic explosion in oklahoma city in 1995.how many litres of gas at 307oc and 1.00atm are formed by the explosive decomposition of 15kg of ammonium nitrate to nitrogen, …

More Similar Questions