3. determine which of the values in the first row need to be used for each question and solve
glucose ( h_f = 46179 , ext{j/g} ) glucose ( c = 1.21 , ext{j/g}^circ ext{c} ) ethanol ( h_f = 189.1 , ext{j/g} ) ethanol ( h_v = 853 , ext{j/g} ) ethanol ( c = 2.46 , ext{j/g}^circ ext{c} )
iron ( c = 0.45 , ext{j/g}^circ ext{c} ) mercury ( c = 0.14 , ext{j/g}^circ ext{c} ) gold ( c = 0.129 , ext{j/g}^circ ext{c} )
water ( c = 4.184 , ext{j/g}^circ ext{c} ) water ( h_f = 334 , ext{j/g} ) water ( h_v = 2260 , ext{j/g} )
how much heat does it take to fully melt 24.6g of glucose at its melting point?
is melting an endothermic or exothermic process?
what mass of water loses 3592 j of heat when completely freezing at its freezing temperature?
is freezing an endothermic or exothermic process?
35.2g of liquid ethanol at ( 70.1^circ ext{c} ) is heated until it reaches its boiling point of ( 78.37^circ ext{c} ). more heat is added to it until the entire mass of ethanol is boiled. what is the total ( q ) of the ethanol for heating and boiling it?
is boiling an endothermic or exothermic process?

Question

3. determine which of the values in the first row need to be used for each question and solve
glucose ( h_f = 46179 , 	ext{j/g} )  glucose ( c = 1.21 , 	ext{j/g}^circ	ext{c} )  ethanol ( h_f = 189.1 , 	ext{j/g} )  ethanol ( h_v = 853 , 	ext{j/g} )  ethanol ( c = 2.46 , 	ext{j/g}^circ	ext{c} )
iron ( c = 0.45 , 	ext{j/g}^circ	ext{c} )  mercury ( c = 0.14 , 	ext{j/g}^circ	ext{c} )  gold ( c = 0.129 , 	ext{j/g}^circ	ext{c} )
water ( c = 4.184 , 	ext{j/g}^circ	ext{c} )  water ( h_f = 334 , 	ext{j/g} )  water ( h_v = 2260 , 	ext{j/g} )
how much heat does it take to fully melt 24.6g of glucose at its melting point?
is melting an endothermic or exothermic process?
what mass of water loses 3592 j of heat when completely freezing at its freezing temperature?
is freezing an endothermic or exothermic process?
35.2g of liquid ethanol at ( 70.1^circ	ext{c} ) is heated until it reaches its boiling point of ( 78.37^circ	ext{c} ). more heat is added to it until the entire mass of ethanol is boiled. what is the total ( q ) of the ethanol for heating and boiling it?
is boiling an endothermic or exothermic process?

Accepted Answer

### 1. How much heat does it take to fully melt 24.6g of glucose at its melting point?
# Explanation:
## Step1: Identify the formula for heat of fusion
The heat required to melt a substance at its melting point is given by $ q = m \times H_f $, where $ m $ is the mass and $ H_f $ is the heat of fusion.
## Step2: Substitute the values
Given $ m = 24.6 \, \text{g} $ and $ H_f $ for glucose is $ 46179 \, \text{J/g} $. So, $ q = 24.6 \, \text{g} \times 46179 \, \text{J/g} $.
## Step3: Calculate the heat
$ q = 24.6 \times 46179 = 1136003.4 \, \text{J} $ (approx).
# Answer:
$ 1136003.4 \, \text{J} $ (or more precisely, $ 24.6\times46179 = 1136003.4 \, \text{J} $)

### 2. Is melting an endothermic or exothermic process?
# Brief Explanations:
Melting requires heat to be absorbed by the substance to change from solid to liquid. Endothermic processes absorb heat.
# Answer:
Endothermic

### 3. What mass of water loses 3592 J of heat when completely freezing at its freezing temperature?
# Explanation:
## Step1: Identify the formula for heat of fusion (freezing is reverse of melting)
The heat released during freezing is $ q = m \times H_f $ (here $ q $ is the heat lost, so we can use $ m=\frac{q}{H_f} $).
## Step2: Substitute the values
Given $ q = 3592 \, \text{J} $ and $ H_f $ for water is $ 334 \, \text{J/g} $. So, $ m=\frac{3592}{334} $.
## Step3: Calculate the mass
$ m = \frac{3592}{334}=10.7545 \, \text{g} $ (approx 10.8 g).
# Answer:
$ 10.8 \, \text{g} $ (or $ \frac{3592}{334} = 10.7545 \, \text{g} $)

### 4. Is freezing an endothermic or exothermic process?
# Brief Explanations:
Freezing involves the substance releasing heat to change from liquid to solid. Exothermic processes release heat.
# Answer:
Exothermic

### 5. 35.2g of liquid ethanol at 70.1°C is heated until it reaches its boiling point of 78.37°C. More heat is added to it until the entire mass of ethanol is boiled. What is the total q of the ethanol for heating and boiling it?
# Explanation:
## Step1: Calculate heat for temperature change (heating to boiling point)
The formula for heat during temperature change is $ q_1 = m \times c \times \Delta T $, where $ \Delta T=T_2 - T_1 $. Given $ m = 35.2 \, \text{g} $, $ c = 2.46 \, \text{J/g°C} $, $ T_1 = 70.1°C $, $ T_2 = 78.37°C $. So, $ \Delta T=78.37 - 70.1 = 8.27°C $. Then $ q_1=35.2\times2.46\times8.27 $.
## Step2: Calculate heat for boiling (heat of vaporization)
The formula for heat of vaporization is $ q_2 = m \times H_v $, where $ H_v = 853 \, \text{J/g} $. So, $ q_2 = 35.2\times853 $.
## Step3: Calculate total heat $ q = q_1+q_2 $
First, $ q_1=35.2\times2.46\times8.27 \approx 35.2\times20.3442 = 716.11584 \, \text{J} $.
Second, $ q_2=35.2\times853 = 30025.6 \, \text{J} $.
Total $ q = 716.11584+30025.6 = 30741.71584 \, \text{J} $ (approx).
# Answer:
Approximately $ 30741.72 \, \text{J} $ (or more precisely, $ 35.2\times2.46\times(78.37 - 70.1)+35.2\times853 = 30741.72 \, \text{J} $)

### 6. Is boiling an endothermic or exothermic process?
# Brief Explanations:
Boiling requires heat to be absorbed by the substance to change from liquid to gas. Endothermic processes absorb heat.
# Answer:
Endothermic

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QUESTION IMAGE

Question

Explanation:

1. How much heat does it take to fully melt 24.6g of glucose at its melting point?

Step1: Identify the formula for heat of fusion

Step2: Substitute the values

Step3: Calculate the heat

Step1: Identify the formula for heat of fusion (freezing is reverse of melting)

Step2: Substitute the values

Step3: Calculate the mass

Answer:

2. Is melting an endothermic or exothermic process?