Question 1

How many kilojoules are there in 95.0 Calories?

Accepted Answer

1 Calorie = 4.184 kilojoules
Thus, 95.0 Calories = 95.0 x 4.184 = 397 kilojoules. Therefore, the answer is C, which is 397.

Question 2

Melting point can be defined as the temperature when a solid becomes a liquid.The melting point of the chemical acetone is -95°C.Which state of matter would you expect to exist for acetone at a temperature of -94°C?

Accepted Answer

Since the melting point of acetone is -95°C, at -94°C, it would have just surpassed its melting point, meaning it would exist in a liquid state.

Question 3

Suppose it took 108 joules of energy to raise a bar of gold from 25.0°C to 29.7°C.Given that the specific heat capacity of gold is 0.128 J/g∙°C,what is the mass (in grams)of the bar of gold?

Accepted Answer

We can use the formula:
q = m*c*ΔT

where q is the heat transferred, m is the mass, c is the specific heat capacity, and ΔT is the change in temperature.

Rearranging the formula, we get:
m = q/(c*ΔT)

Substituting the given values, we get:
m = 108 J / (0.128 J/g∙°C * (29.7°C - 25.0°C))
m = 1.8 × 10¹² g

Therefore, the mass of the bar of gold is 1.8 × 10¹² g, which is closest to option B.

Question 4

In calculating the relationship between the amount of heat added to a substance and the corresponding temperature change,the specific heat capacity is usually represented by which symbol?

Accepted Answer

Specific heat capacity is represented by the symbol C. q represents the amount of heat added, ΔT represents the temperature change, and m represents the mass of the substance.

Question 5

What is the value of 27°C on the Kelvin temperature scale?

Accepted Answer

To convert Celsius to Kelvin, you simply add 273 to the Celsius temperature. Therefore, 27°C + 273 = 300K.

Question 6

An energy diagram that shows the reactants having greater energy than the products illustrates an

Accepted Answer

An energy diagram where reactants have greater energy than products indicates that energy is released during the reaction, characterizing it as an exothermic reaction.

Question 7

A 15.0 gram lead ball at 25.0°C was heated with 40.5 joules of heat.Given the specific heat of lead is
0.128 J/g∙°C,what is the final temperature of the lead?

Accepted Answer

The answer of A 15.0 gram lead ball at 25.0°C...

Question 8

If a solid piece of shiny sodium metal is exposed to chlorine gas,a large amount of heat is released and the white solid sodium chloride (table salt)forms.Based on this information,which of the following statements is TRUE?

Accepted Answer

The given information mentions that a large amount of heat is released, which indicates an exothermic process. Therefore, option D is the correct choice. Options A, B, and C are incorrect as they do not align with the given information.

Question 9

In order,what is the freezing point,room temperature and boiling point of water according to the Celsius scale?

Accepted Answer

The freezing point of water is 0 degrees Celsius, room temperature is generally considered to be around 25 degrees Celsius, and the boiling point of water is 100 degrees Celsius. Choice C correctly lists these temperatures in order.

Question 10

What is the specific heat (J/g∙°C)of a metal object whose temperature increases by 3.0°C when 17.5 g of metal was heated with 38.5 J?

Accepted Answer

The equation for calculating heat (q) is:

q = m x c x ΔT

Where:
m = mass of the metal (in grams)
c = specific heat of the metal (in J/g∙°C)
ΔT = change in temperature (in °C)

Rearranging the equation to solve for specific heat (c), we get:

c = q / (m x ΔT)

Plugging in the values we know:

m = 17.5 g
ΔT = 3.0°C
q = 38.5 J

c = 38.5 J / (17.5 g x 3.0°C)
c = 0.73 J/g∙°C

Therefore, the specific heat of the metal object is 0.73 J/g∙°C, which is choice C.

Question 11

If a particular process is endothermic,the reverse process must be a (an)

Accepted Answer

If a process is endothermic, it means heat is absorbed by the system. Therefore, the reverse process would be exothermic, as heat would be released by the system.

Question 12

The boiling point of water is
(1)212 °F (2)0°C (3)373 K

Accepted Answer

- Choice 1 is incorrect because 212°F is the boiling point of water in Fahrenheit, but the question is asking for the boiling point in Celsius or Kelvin.
- Choice 2 is incorrect because 0°C is the freezing point of water in Celsius, not the boiling point. 
- Choice 3 is correct because 373 K is the boiling point of water in Kelvin, which is equivalent to 100°C in Celsius. Therefore, the boiling point of water is 373 K or 100°C.

Question 13

When 49.5 J of heat was transferred to 7.3 g iron at 22°C,the temperature of iron increases to 37°C.What is the specific heat of iron in J/g∙°C?

Accepted Answer

The answer of When 49.5 J of heat was transferred...

Question 14

Consider the following specific heats of metals.
Metal Specific Heat (J/g∙°C)
Aluminum 0.903
Copper 0.385
Gold 0.128
Iron 0.449
Silver 0.235
If the same amount of heat is added to 50.0 g samples of each of the metals,which are all at the same temperature,which metal will reach the highest temperature?

Accepted Answer

The metal that will reach the highest temperature will be the one with the lowest specific heat. This is because metals with lower specific heats require less heat to raise their temperature compared to metals with higher specific heats. Among the given options, gold has the lowest specific heat of 0.128 J/g∙°C, so it will reach the highest temperature when the same amount of heat is added to a 50.0 g sample of each metal.

Question 15

In order,what is the freezing point,room temperature and boiling point of water according to the Fahrenheit scale?

Accepted Answer

According to the Fahrenheit scale, water freezes at 32°F, the room temperature is around 75°F, and water boils at 212°F. Option A correctly lists these temperatures in order.

Question 16

What is the value of 27°C on the Fahrenheit temperature scale?

Accepted Answer

The answer of What is the value of 27°C on...

Question 17

From the following list of substances and heat capacities,choose the one that will have the lowest temperature after absorbing 100.0 kJ of heat.Assume identical masses of each substance start at the same initial temperature.

Accepted Answer

The substance with the lowest heat capacity will have the highest temperature change for a given amount of heat absorbed. Conversely, the substance with the highest heat capacity will have the lowest temperature change for a given amount of heat absorbed. In this case, water has the highest heat capacity, so it will have the lowest temperature change, and therefore the lowest final temperature, after absorbing 100.0 kJ of heat.

Question 18

How much heat (kJ)is needed to raise the temperature of 100.0 grams of water from 25.0°C to 50.0°C?

Accepted Answer

The heat required can be calculated using the formula q = mcΔT. For water, m = 100.0 g, c = 4.18 J/g°C, and ΔT = 25°C. Converting to kJ, q = 100.0 g * 4.18 J/g°C * 25°C = 10450 J = 10.45 kJ, which rounds to 10.5 kJ.

Question 19

What is the value of 98 °F in units of °C?

Accepted Answer

To convert from Fahrenheit to Celsius, we use the formula C = (F-32) * 5/9. Plugging in F = 98, we get C = (98-32) * 5/9 = 37. Therefore, the value of 98 °F in units of °C is 37.

Question 20

What is the value of 335 K on the Celsius temperature scale?

Accepted Answer

The answer of What is the value of 335 K...

Quiz 3: Matter and Energy

How many kilojoules are there in 95.0 Calories?

Melting point can be defined as the temperature when a solid becomes a liquid.The melting point of the chemical acetone is -95°C.Which state of matter would you expect to exist for acetone at a temperature of -94°C?

Suppose it took 108 joules of energy to raise a bar of gold from 25.0°C to 29.7°C.Given that the specific heat capacity of gold is 0.128 J/g∙°C,what is the mass (in grams) of the bar of gold?

In calculating the relationship between the amount of heat added to a substance and the corresponding temperature change,the specific heat capacity is usually represented by which symbol?

What is the value of 27°C on the Kelvin temperature scale?

An energy diagram that shows the reactants having greater energy than the products illustrates an

A 15.0 gram lead ball at 25.0°C was heated with 40.5 joules of heat.Given the specific heat of lead is 0.128 J/g∙°C,what is the final temperature of the lead?

If a solid piece of shiny sodium metal is exposed to chlorine gas,a large amount of heat is released and the white solid sodium chloride (table salt) forms.Based on this information,which of the following statements is TRUE?