Answer:
10 g
Explanation:
Right from the start, just by inspecting the values given, you can say that the answer will be
10 g
.
Now, here's what that is the case.
As you know, a substance's specific heat tells you how much heat is needed to increase the temperature of
1 g
of that substance by
1
∘
C
.
Water has a specific heat of approximately
4.18
J
g
∘
C
. This tells you that in order to increase the temperature of
1 g
of water by
1
∘
C
, you need to provide
4.18 J
of heat.
Now, how much heat would be required to increase the temperature of
1 g
of water by
10
∘
C
?
Well, you'd need
4.18 J
to increase it by
1
∘
C
, another
4.18 J
to increase it by another
1
∘
C
, and so on. This means that you'd need
4.18 J
×
10
=
41.8 J
to increase the temperature of
1 g
of water by
10
∘
C
.
Now look at the value given to you. If you need
41.8 J
to increase the temperature of
1 g
of water by
10
∘
C
, what mass of water would require
10
times as much heat to increase its temperature by
10
∘
C
?
1 g
×
10
=
10 g
And that's your answer.
Mathematically, you can calculate this by using the equation
q
=
m
⋅
c
⋅
Δ
T
, where
q
- heat absorbed/lost
m
- the mass of the sample
c
- the specific heat of the substance
Δ
T
- the change in temperature, defined as final temperature minus initial temperature
Plug in your values to get
418
J
=
m
⋅
4.18
J
g
∘
C
⋅
(
20
−
10
)
∘
C
m
=
418
4.18
⋅
10
=
10 g
is the number of moles of the solute in the solution.
is the concentration of the solution.
for the initial solution.
is the volume of the solution. For the initial solution,
for the initial solution.
for the diluted solution.
.