The specific heat of water is 4.18 J/(g·°C). How much energy is necessary to raise 15 g of water by 20 °C? (Use the equation Q = mcpΔT ) About the author Rylee
Answer: First thing first, you mistyped the specific heat of water, which should be c water = 4.18 J g ∘ C Now, a substance’s specific heat tells you how much heat is required to increase the temperature of 1 g of that substance by 1 ∘ C . In the case of water, you would need 4.18 J to increase the temperature of 1 g of water by 1 ∘ C . Notice that your sample of water has a mass of 1 g as well, which means that the only factor that will determine the amount of heat needed will be the difference in temperature. The equation that establishes a relationshop between heat and change in temperature looks like this q = m ⋅ c ⋅ Δ T , where q – heat absorbed c – the specific heat of the substance, in your case of water Δ T – the change in temperature, defined as the difference between the final temperature and the initial temperature Plug in your values and solve for q to get q = 1.00 g ⋅ 4.18 J g ⋅ ∘ C ⋅ ( 83.7 − 26.5 ) ∘ C q = 239.096 J Reply
Answer:
First thing first, you mistyped the specific heat of water, which should be
c
water
=
4.18
J
g
∘
C
Now, a substance’s specific heat tells you how much heat is required to increase the temperature of
1 g
of that substance by
1
∘
C
.
In the case of water, you would need
4.18 J
to increase the temperature of
1 g
of water by
1
∘
C
.
Notice that your sample of water has a mass of
1 g
as well, which means that the only factor that will determine the amount of heat needed will be the difference in temperature.
The equation that establishes a relationshop between heat and change in temperature looks like this
q
=
m
⋅
c
⋅
Δ
T
, where
q
– heat absorbed
c
– the specific heat of the substance, in your case of water
Δ
T
– the change in temperature, defined as the difference between the final temperature and the initial temperature
Plug in your values and solve for
q
to get
q
=
1.00
g
⋅
4.18
J
g
⋅
∘
C
⋅
(
83.7
−
26.5
)
∘
C
q
=
239.096 J