Question

1. Silicon is commonly used as a semiconductor in electronic devices such as cellphones, transistors, and circuit boards. The specific heat of silicon is 0.705

∙℃ and its molar mass is 28.09
.
A. What is the energy required to increase the temperature of 325.7g of silicon by 200°C?

B. What is the energy required to increase the temperature of 8.0 mol of silicon by 10°C?

C. What is the energy required to increase the temperature of 0.089 kg of silicon from
25°C to 69°C?

2. A food scientist student wants to determine the specific heat of ethanol experimentally. The student placed a 182 mL of water at 18.7°C in a bomb calorimeter. Then, he heated a 42.31 mL of ethanol (C2H5OH) to 106.9°C. After the alcohol cools, the observed final temperature of ethanol and water is 18.7°C. What is the specific heat capacity of ethanol? Assume that the student used a perfect calorimeter with all the heat released by the ethanol is absorbed by water. The densities of water and ethanol are 1 g/mL and 0.789 g/mL, respectively.

3. A 53.23 mL of sunflower oil and a 71.04 mL of coconut oil are heated to 153.0°C. The mixture of sunflower oil and coconut oil is added into 128 mL of water at 25.0°C.
Determine the final temperature of sunflower oil, coconut oil, and water mixture assuming that no heat is released to the surroundings. The specific heat capacities of sunflower oil and coconut oil are 2.302 ∙℃
and 2.100 ∙℃, respectively. The density of sunflower oil is 0.929 g/mL, while 0.926 g/mL for coconut oil.



please help me this is important

Answer 1

1. A. The energy required to increase the temperature of 325.7g of silicon by 200°C can be calculated using the formula:

Q = m * c * ΔT

Where Q is the energy required, m is the mass of the substance, c is the specific heat, and ΔT is the change in temperature.

Plugging in the values, we get:

Q = 325.7 g * 0.705 J/(g∙°C) * 200°C

Q = 45,918.6 J or 45.9 kJ (to three significant figures)

Therefore, the energy required to increase the temperature of 325.7g of silicon by 200°C is 45.9 kJ.

B. To calculate the energy required to increase the temperature of 8.0 mol of silicon by 10°C, we first need to calculate the mass of the silicon. This can be done using the molar mass of silicon:

m = n * M

Where m is the mass, n is the number of moles, and M is the molar mass.

Plugging in the values, we get:

m = 8.0 mol * 28.09 g/mol

m = 224.72 g

Now we can use the same formula as before:

Q = m * c * ΔT

Q = 224.72 g * 0.705 J/(g∙°C) * 10°C

Q = 1,579.1 J or 1.58 kJ (to two significant figures)

Therefore, the energy required to increase the temperature of 8.0 mol of silicon by 10°C is 1.58 kJ.

C. The energy required to increase the temperature of 0.089 kg of silicon from 25°C to 69°C can be calculated using the same formula as before:

Q = m * c * ΔT

Q = 0.089 kg * 0.705 J/(g∙°C) * (69°C - 25°C)

Q = 2,024.1 J or 2.02 kJ (to two significant figures)

Therefore, the energy required to increase the temperature of 0.089 kg of silicon from 25°C to 69°C is 2.02 kJ.

2. To calculate the specific heat capacity of ethanol, we can use the formula:

Q = m * c * ΔT

Where Q is the energy released by the ethanol, m is the mass of the ethanol, c is the specific heat capacity of ethanol, and ΔT is the change in temperature of the ethanol-water mixture.

First, we need to calculate the energy absorbed by the water:

Qwater = mwater * cwater * ΔTwater

Where Qwater is the energy absorbed by the water, mwater is the mass of the water, cwater is the specific heat capacity of water (4.184 J/(g∙°C)), and ΔTwater is the change in temperature of the water.

Plugging in the values, we get:

Qwater = 182 g * 4.184 J/(g∙°C) * (18.7°C - 18.7°C)

Qwater = 0 J

Since the calorimeter is perfect, all the heat released by the ethanol is absorbed by the water, and thus the energy released by the ethanol is equal to the energy absorbed by the water:

Qethanol = Qwater

Plugging in the values, we get:

Qethanol = m * c * ΔT

Qethanol = 42.31 g * c * (106.9°C - 18.7°C