Respuesta :
Answer : The amount of heat energy needed from microwave will be, 18412.5 calories and 77037.9 joules
Solution : Given,
Initial temperature = [tex]25^oC[/tex]
Final temperature = [tex]100^oC[/tex]
Specific heat of water = [tex]1cal/g^oC[/tex]
Density of water = 0.99 g/ml
Volume of water = 250 ml
First we have to calculate the mass of substance.
[tex]Mass=Density\times Volume=0.99g/ml\times 250ml=247.5g[/tex]
Now we have to calculate the amount of heat energy needed.
Formula used :
[tex]Q=m\times c\times \Delta T=m\times c\times (T_2-T_1)[/tex]
where,
Q = heat energy gained
c = specific heat of water
[tex]T_1[/tex] = initial temperature
[tex]T_2[/tex] = final temperature
Now put all the given values in the above formula, we get
[tex]Q=(247.5g)\times (1cal/g^oC)\times (100-25)^oC[/tex]
[tex]Q=18412.5cal[/tex]
The amount of heat energy needed in calories = 18412.5 cal
The amount of heat energy needed in joules = (4.184 × 18412.5) = 77037.9 J
Conversion used : (1 calorie = 4.184 joules)
Therefore, the amount of heat energy needed from microwave will be, 18412.5 calories and 77037.9 joules
Answer: The amount of heat needed by the microwave is 18750 Cal or 78450 J
Explanation:
To calculate the mass of water, we use the equation:
[tex]\text{Density of substance}=\frac{\text{Mass of substance}}{\text{Volume of substance}}[/tex]
Density of water = 1 g/mL
Volume of water = 250 mL
Putting values in above equation, we get:
[tex]1g/mL=\frac{\text{Mass of water}}{250mL}\\\\\text{Mass of water}=(1g/mL\times 250mL)=250g[/tex]
To calculate the amount of heat absorbed, we use the equation:
[tex]q=mc\Delta T[/tex]
where,
m = mass of water = 250 g
c = specific heat capacity of water = 1 Cal/g°C
[tex]\Delta T[/tex] = change in temperature = [tex]T_2-T_1=100^oC-25^oC=75^oC[/tex]
Putting values in above equation, we get:
[tex]q=250g\times 1Cal/g.^oC\times 75^oC\\\\q=18750Cal[/tex]
Converting the amount of heat absorbed in Joules, we use the conversion factor:
1 Cal = 4.184 J
So, [tex]18750Cal\times \frac{4.184J}{1Cal}=78450J[/tex]
Hence, the amount of heat needed by the microwave is 18750 Cal or 78450 J
