Question

The specific heat capacity of silver is 0.24 J/°C ·g.
A) Calculate the energy required to raise the temperature of 150.0 g Ag from 273 K to 298 K.
B) Calculate the energy required to raise the temperature of 1.0 mole of Ag by 1.08C (called the molar heat capacity of silver).
C. It takes 1.25 kJ of energy to heat a sample of pure silver from 12.08°C to 15.28°C. Calculate the mass of the sample of silver.

Answer 1

Answer:

A) 900 J

B) 27.96 J

C) 1,628 J ≅ 1.63 kJ

Explanation:

The heat absorbed by the metal (silver) - or energy required to heat it -  is calculated as:

heat = mass x Cp x ΔT

Where Cp is the heat capacity (0.24 J/°C ·g) and ΔT is the change in temperature (final T - initial T).

A) Given:

mass = 150.0 g

final T = 298 K = 25°C

initial T = 273 K = 0°C

We calculate the energy in J to raise the temperature:

heat = mass x Cp x (final T - initial T)

       = 150 .0 g x 0.24 J/°C ·g x (25°C - 0°C )

       = 900 J

B) Given:

moles Ag= 1.0 mol

ΔT = 1.08°C

We first calculate the mass of silver (Ag) by multiplying the moles of Ag by the molar mass of Ag (MM = 107.9 g/mol)

mass = moles x MM = 1.0 mol Ag x 107.9 g/mol Ag = 107.9 g

Then, we calculate the heat required:

heat = mass x Cp x ΔT = 107.9 g x 0.24 J/°C ·g x 1.08°C = 27.96 J

C) Given:

heat = 1.25 kJ = 1,250 J

final T = 15.28°C

initial T = 12.08°C

We first calculate the change in temperature:

ΔT = final T - initial T = 15.28°C - 12.08°C = 3.2°C

Then, we calculate the mass of silver:

mass = heat/(Cp x ΔT) = 1,250 J/(0.24 J/°C ·g x 3.2°C) = 1,628 J ≅ 1.63 kJ

Answer 2

Taking into account the definition of calorimetry:

A) the energy required to raise the temperature of 150 g Ag from 273 K to 298 K is 900 J.

B) the energy required to raise the temperature of 1.0 mole of Ag by 1.08 °C is 27.96 J.

C) the mass of the sample of silver is 1627.60 g.

Calorimetry is the measurement and calculation of the amounts of heat exchanged by a body or a system.

Sensible heat is defined as the amount of heat that a body absorbs or releases without any changes in its physical state (phase change).

So, the expression that allows to calculate heat exchanges is:

Q = c× m× ΔT

where Q is the heat exchanged by a body of mass m, made up of a specific heat substance c and where ΔT is the temperature variation.

• A)

In this case, you know:

• c= 0.24 $\frac{J}{Cg}$
• m= 150 g
• ΔT= Tfinal - Tinitial= 298 K - 273 K= 25 K= 25 C  Being a temperature difference, it has the same value in ° C and ° K units

Replacing:

Q= 0.24$\frac{J}{Cg}$ × 150 g× 25 C

Solving:

Q= 900 J

In summary, the energy required to raise the temperature of 150 g Ag from 273 K to 298 K is 900 J.

• B)

In this case, you know:

• c= 0.24 $\frac{J}{Cg}$
• m= 107.87 grams by definition of molar mass, this is the amount of mass a substance contains in one mole. The molar mass of Ag is 107.87 $\frac{g}{mole}$
• ΔT= 1.08 C

Replacing:

Q= 0.24$\frac{J}{Cg}$ × 107.87 g× 1.08 C

Solving:

Q= 27.96 J

In summary, the energy required to raise the temperature of 1.0 mole of Ag by 1.08 °C is 27.96 J.

• C)

In this case, you know:

• Q= 1.25 kJ= 1250 J
• c= 0.24 $\frac{J}{Cg}$
• m= ?
• ΔT= Tfinal - Tinitial= 15.28 C - 12.08 C= 3.2 C

Replacing:

1250 J= 0.24$\frac{J}{Cg}$ × m× 3.2 C

Solving:

m= 1250 J÷ (0.24$\frac{J}{Cg}$ × 3.2 C)

m= 1627.6 g

In summary, the mass of the sample of silver is 1627.60 g.

Learn more about calorimetry:

• brainly.com/question/11586486?referrer=searchResults
• brainly.com/question/24724338?referrer=searchResults
• brainly.com/question/11586486?referrer=searchResults
• brainly.com/question/24724338?referrer=searchResults