Calculate the amount of Joules needed to warm water from 21 Celsius to 66 celsius to make a cup of hot cocoa. The cup holds 308 g of water.

This will require

266.9

k

J

of heat energy.

Explanation:

To calculate the energy required to raise the temperature of any given substance, here's what you require:

The mass of the material,

m

The temperature change that occurs,

Δ

T

The specific heat capacity of the material,

c

(which you can look up). This is the amount of heat required to raise 1 gram of that substance by 1°C.

Here is a source of values of c for different substances:

Once you have all that, this is the equation:

Q

=

m

×

c

×

Δ

T

(

Q

is usually used to symbolize that heat required in a case like this.)

2h2o2--> 2h2o + o2

this reaction is of the spontaneous decomposition of hydrogen peroxide down into water and oxygen.

add 2 molecules of hydrogen peroxide and 2 molecules of water. since oxygen is naturally diatomic, the total number of atoms of each element is now the same on both sides of the equation so it is balanced.

this may not be entirely correct but let me know.