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olga_2 [115]
2 years ago
15

If an ice cube weighing 25.0 g with an initial

Chemistry
1 answer:
riadik2000 [5.3K]2 years ago
3 0

Answer:

11

∘

C

Explanation:

As far as solving this problem goes, it is very important that you do not forget to account for the phase change underwent by the solid water at

0

∘

C

to liquid at

0

∘

C

.

The heat needed to melt the solid at its melting point will come from the warmer water sample. This means that you have

q

1

+

q

2

=

−

q

3

(

1

)

, where

q

1

- the heat absorbed by the solid at

0

∘

C

q

2

- the heat absorbed by the liquid at

0

∘

C

q

3

- the heat lost by the warmer water sample

The two equations that you will use are

q

=

m

⋅

c

⋅

Δ

T

, where

q

- heat absorbed/lost

m

- the mass of the sample

c

- the specific heat of water, equal to

4.18

J

g

∘

C

Δ

T

- the change in temperature, defined as final temperature minus initial temperature

and

q

=

n

⋅

Δ

H

fus

, where

q

- heat absorbed

n

- the number of moles of water

Δ

H

fus

- the molar heat of fusion of water, equal to

6.01 kJ/mol

Use water's molar mass to find how many moles of water you have in the

100.0-g

sample

100.0

g

⋅

1 mole H

2

O

18.015

g

=

5.551 moles H

2

O

So, how much heat is needed to allow the sample to go from solid at

0

∘

C

to liquid at

0

∘

C

?

q

1

=

5.551

moles

⋅

6.01

kJ

mole

=

33.36 kJ

This means that equation

(

1

)

becomes

33.36 kJ

+

q

2

=

−

q

3

The minus sign for

q

3

is used because heat lost carries a negative sign.

So, if

T

f

is the final temperature of the water, you can say that

33.36 kJ

+

m

sample

⋅

c

⋅

Δ

T

sample

=

−

m

water

⋅

c

⋅

Δ

T

water

More specifically, you have

33.36 kJ

+

100.0

g

⋅

4.18

J

g

∘

C

⋅

(

T

f

−

0

)

∘

C

=

−

650

g

⋅

4.18

J

g

∘

C

⋅

(

T

f

−

25

)

∘

C

33.36 kJ

+

418 J

⋅

(

T

f

−

0

)

=

−

2717 J

⋅

(

T

f

−

25

)

Convert the joules to kilojoules to get

33.36

kJ

+

0.418

kJ

⋅

T

f

=

−

2.717

kJ

⋅

(

T

f

−

25

)

This is equivalent to

0.418

⋅

T

f

+

2.717

⋅

T

f

=

67.925

−

33.36

T

f

=

34.565

0.418

+

2.717

=

11.026

∘

C

Rounded to two sig figs, the number of sig figs you have for the mass of warmer water, the answer will be

T

f

=

11

∘

C

Explanation:

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To what volume should you dilute 134 mL of an 8.00 M CuCl2 solution so that 48.0 mL of the diluted solution contains 5.89 g CuCl
Tom [10]

Answer:

Explanation:

Number of moles of CuCl2 initially present = volume * molar concentration

= 0.134 * 8

= 1.072 mol.

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= 134.5 g/mol

Mass of CuCl2 = molar mass * number of moles

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4 0
3 years ago
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Leto [7]
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Ringer's solution at 23 degree Celsius for normal heart rate
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4 0
3 years ago
What volume of propane (C3H8) is required to produce 165 liters of water according to the following reaction? (All gases are at
inna [77]

Answer:

We need 41.2 L of propane

Explanation:

Step 1: Data given

volume of H2O = 165 L

Step 2:  The balanced equation

C3H8(g) + 5O2(g) → 3CO2(g) + 4H2O(g)

Step 3: Calculate moles of H2O

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Step 5: Calculate volume of propane

1 mol = 22.4 L

1.84 moles = 41.2 L

We need 41.2 L of propane

6 0
3 years ago
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Virty [35]
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4 0
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babymother [125]

Answer:

B

Explanation:

7 0
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