Answer:
Q = -627.6 J
Explanation:
Mass, m = 15 grams
Initial temperature, [tex]T_i=40^{\circ} C[/tex]
Final temperature, [tex]T_f=30^{\circ} C[/tex]
We need to find the amount of heat released by this much of sample of water. We know that heat released is given by the below formula :
[tex]Q=mc\Delta T[/tex]
c is specific heat of water, [tex]c=4.184\ J/g-K[/tex]
[tex]\Delta T=T_f-T_i\\\\=(30^{\circ}-40^{\circ} )\ C\\\\=-10^{\circ} C\\\\=-10\ K[/tex]
So,
[tex]Q=15\times 4.184\times -10\\\\Q=-627.6\ J[/tex]
Hence, 627.6 J of heat is released and negative sign shows that energy is being given off.