Chemistry

Practice Questions

ACT Science › Chemistry

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1

During digestion, the energy in food is converted to energy the body can use. Scientists use calorimetry experiments to measure the calories, or energy, provided by food when it is digested or burned.

The relationship used to find the heat transferred energy is given by , where is the mass of the material, is the given specific heat capacity, and is the change in temperature of the material.

In this experiment, food was burned over a Bunsen burner under a can of 200 ml of water. The temperature change of the water and mass change of the food can be used to determine the calories in four different food items.

Table 1 shows the values of the change of mass of the food items, the change in temperature of the water and the energy. Table 2 shows the energy to mass ratio of three of those food items.

Table 1

Roasted Peanut Peanut Cracker Cheese Puff

Water Temp. Initial 23.9 °C 33.2 °C 40.3 °C 53.9 °C

Water Temp. Final 30.0 °C 40.9 °C 55.9 °C 62.8 °C

Food Mass Initial 0.69 g 0.61 g 3.21 g 1.22 g

Food Mass Final 0.38 g 0.21 g 0.91 g 0.48 g

Energy 1.22 Cal 1.54 Cal 3.12 Cal 1.78 Cal

Table 2

Sample Energy to Mass Ratio (Cal/g)

1 1.36

2 3.93

3 2.40

According to information from Tables 1 and 2, order the samples' energy to mass ratios from least to greatest.

2

During digestion, the energy in food is converted to energy the body can use. Scientists use calorimetry experiments to measure the calories, or energy, provided by food when it is digested or burned.

The relationship used to find the heat transferred energy is given by , where is the mass of the material, is the given specific heat capacity, and is the change in temperature of the material.

In this experiment, food was burned over a Bunsen burner under a can of 200 ml of water. The temperature change of the water and mass change of the food can be used to determine the calories in four different food items.

Table 1 shows the values of the change of mass of the food items, the change in temperature of the water and the energy. Table 2 shows the energy to mass ratio of three of those food items.

Table 1

Roasted Peanut Peanut Cracker Cheese Puff

Water Temp. Initial 23.9 °C 33.2 °C 40.3 °C 53.9 °C

Water Temp. Final 30.0 °C 40.9 °C 55.9 °C 62.8 °C

Food Mass Initial 0.69 g 0.61 g 3.21 g 1.22 g

Food Mass Final 0.38 g 0.21 g 0.91 g 0.48 g

Energy 1.22 Cal 1.54 Cal 3.12 Cal 1.78 Cal

Table 2

Sample Energy to Mass Ratio (Cal/g)

1 1.36

2 3.93

3 2.40

According to information from Tables 1 and 2, order the samples' energy to mass ratios from least to greatest.

3

During digestion, the energy in food is converted to energy the body can use. Scientists use calorimetry experiments to measure the calories, or energy, provided by food when it is digested or burned.

The relationship used to find the heat transferred energy is given by , where is the mass of the material, is the given specific heat capacity, and is the change in temperature of the material.

In this experiment, food was burned over a Bunsen burner under a can of 200 ml of water. The temperature change of the water and mass change of the food can be used to determine the calories in four different food items.

Table 1 shows the values of the change of mass of the food items, the change in temperature of the water and the energy. Table 2 shows the energy to mass ratio of three of those food items.

Table 1

Roasted Peanut Peanut Cracker Cheese Puff

Water Temp. Initial 23.9 °C 33.2 °C 40.3 °C 53.9 °C

Water Temp. Final 30.0 °C 40.9 °C 55.9 °C 62.8 °C

Food Mass Initial 0.69 g 0.61 g 3.21 g 1.22 g

Food Mass Final 0.38 g 0.21 g 0.91 g 0.48 g

Energy 1.22 Cal 1.54 Cal 3.12 Cal 1.78 Cal

Table 2

Sample Energy to Mass Ratio (Cal/g)

1 1.36

2 3.93

3 2.40

Based on the results shown in Table 1 from the experiment, what is the relationship between the mass change of the food sample and the calories in the food?

4

During digestion, the energy in food is converted to energy the body can use. Scientists use calorimetry experiments to measure the calories, or energy, provided by food when it is digested or burned.

The relationship used to find the heat transferred energy is given by , where is the mass of the material, is the given specific heat capacity, and is the change in temperature of the material.

In this experiment, food was burned over a Bunsen burner under a can of 200 ml of water. The temperature change of the water and mass change of the food can be used to determine the calories in four different food items.

Table 1 shows the values of the change of mass of the food items, the change in temperature of the water and the energy. Table 2 shows the energy to mass ratio of three of those food items.

Table 1

Roasted Peanut Peanut Cracker Cheese Puff

Water Temp. Initial 23.9 °C 33.2 °C 40.3 °C 53.9 °C

Water Temp. Final 30.0 °C 40.9 °C 55.9 °C 62.8 °C

Food Mass Initial 0.69 g 0.61 g 3.21 g 1.22 g

Food Mass Final 0.38 g 0.21 g 0.91 g 0.48 g

Energy 1.22 Cal 1.54 Cal 3.12 Cal 1.78 Cal

Table 2

Sample Energy to Mass Ratio (Cal/g)

1 1.36

2 3.93

3 2.40

Based on the results shown in Table 1 from the experiment, what is the relationship between the mass change of the food sample and the calories in the food?

5

During digestion, the energy in food is converted to energy the body can use. Scientists use calorimetry experiments to measure the calories, or energy, provided by food when it is digested or burned.

The relationship used to find the heat transferred energy is given by , where is the mass of the material, is the given specific heat capacity, and is the change in temperature of the material.

In this experiment, food was burned over a Bunsen burner under a can of 200 ml of water. The temperature change of the water and mass change of the food can be used to determine the calories in four different food items.

Table 1 shows the values of the change of mass of the food items, the change in temperature of the water and the energy. Table 2 shows the energy to mass ratio of three of those food items.

Table 1

Roasted Peanut Peanut Cracker Cheese Puff

Water Temp. Initial 23.9 °C 33.2 °C 40.3 °C 53.9 °C

Water Temp. Final 30.0 °C 40.9 °C 55.9 °C 62.8 °C

Food Mass Initial 0.69 g 0.61 g 3.21 g 1.22 g

Food Mass Final 0.38 g 0.21 g 0.91 g 0.48 g

Energy 1.22 Cal 1.54 Cal 3.12 Cal 1.78 Cal

Table 2

Sample Energy to Mass Ratio (Cal/g)

1 1.36

2 3.93

3 2.40

Based on the information in Table 1, what variables must be measured in order to calculate the energy of the food samples?

6

During digestion, the energy in food is converted to energy the body can use. Scientists use calorimetry experiments to measure the calories, or energy, provided by food when it is digested or burned.

The relationship used to find the heat transferred energy is given by , where is the mass of the material, is the given specific heat capacity, and is the change in temperature of the material.

In this experiment, food was burned over a Bunsen burner under a can of 200 ml of water. The temperature change of the water and mass change of the food can be used to determine the calories in four different food items.

Table 1 shows the values of the change of mass of the food items, the change in temperature of the water and the energy. Table 2 shows the energy to mass ratio of three of those food items.

Table 1

Roasted Peanut Peanut Cracker Cheese Puff

Water Temp. Initial 23.9 °C 33.2 °C 40.3 °C 53.9 °C

Water Temp. Final 30.0 °C 40.9 °C 55.9 °C 62.8 °C

Food Mass Initial 0.69 g 0.61 g 3.21 g 1.22 g

Food Mass Final 0.38 g 0.21 g 0.91 g 0.48 g

Energy 1.22 Cal 1.54 Cal 3.12 Cal 1.78 Cal

Table 2

Sample Energy to Mass Ratio (Cal/g)

1 1.36

2 3.93

3 2.40

Based on the information in Table 1, what variables must be measured in order to calculate the energy of the food samples?

7

During digestion, the energy in food is converted to energy the body can use. Scientists use calorimetry experiments to measure the calories, or energy, provided by food when it is digested or burned.

The relationship used to find the heat transferred energy is given by , where is the mass of the material, is the given specific heat capacity, and is the change in temperature of the material.

In this experiment, food was burned over a Bunsen burner under a can of 200 ml of water. The temperature change of the water and mass change of the food can be used to determine the calories in four different food items.

Table 1 shows the values of the change of mass of the food items, the change in temperature of the water and the energy. Table 2 shows the energy to mass ratio of three of those food items.

Table 1

Roasted Peanut Peanut Cracker Cheese Puff

Water Temp. Initial 23.9 °C 33.2 °C 40.3 °C 53.9 °C

Water Temp. Final 30.0 °C 40.9 °C 55.9 °C 62.8 °C

Food Mass Initial 0.69 g 0.61 g 3.21 g 1.22 g

Food Mass Final 0.38 g 0.21 g 0.91 g 0.48 g

Energy 1.22 Cal 1.54 Cal 3.12 Cal 1.78 Cal

Table 2

Sample Energy to Mass Ratio (Cal/g)

1 1.36

2 3.93

3 2.40

The student performing the experiment concluded that eating an amount of crackers would provide an athlete with more energy than eating the same amount of any of the other food samples. Do the results in Tables 1 and 2 support this claim?

8

During digestion, the energy in food is converted to energy the body can use. Scientists use calorimetry experiments to measure the calories, or energy, provided by food when it is digested or burned.

The relationship used to find the heat transferred energy is given by , where is the mass of the material, is the given specific heat capacity, and is the change in temperature of the material.

In this experiment, food was burned over a Bunsen burner under a can of 200 ml of water. The temperature change of the water and mass change of the food can be used to determine the calories in four different food items.

Table 1 shows the values of the change of mass of the food items, the change in temperature of the water and the energy. Table 2 shows the energy to mass ratio of three of those food items.

Table 1

Roasted Peanut Peanut Cracker Cheese Puff

Water Temp. Initial 23.9 °C 33.2 °C 40.3 °C 53.9 °C

Water Temp. Final 30.0 °C 40.9 °C 55.9 °C 62.8 °C

Food Mass Initial 0.69 g 0.61 g 3.21 g 1.22 g

Food Mass Final 0.38 g 0.21 g 0.91 g 0.48 g

Energy 1.22 Cal 1.54 Cal 3.12 Cal 1.78 Cal

Table 2

Sample Energy to Mass Ratio (Cal/g)

1 1.36

2 3.93

3 2.40

The student performing the experiment concluded that eating an amount of crackers would provide an athlete with more energy than eating the same amount of any of the other food samples. Do the results in Tables 1 and 2 support this claim?

9

A student performed the following procedures to study various photosynthetic pigments (light-absorbing chemicals) in tree leaves and the wavelengths of light they absorb.

Experiment 1:

The student obtained samples of leaves from oaks, maples, ashes, sycamores, and poplars. Each leaf sample was ground separately with a mortar and pestle to release the pigments, and then each sample was suspended in water to make a colored solution of the pigment. The student then measured the absorption spectrum (a graph of how much light is absorbed by a pigment at varying wavelengths of light) of each solution in a device called a spectrophotometer. The setup of a spectrophotometer is shown below in Diagram 1.

Spectrophotometer

The light source emits white light, which is split into its various wavelengths by the prism. Next, a slit, which can be moved up or down to select a particular wavelength, is used to transmit just a single wavelength to the sample. The sample absorbs a fraction of this light that is characteristic to the pigment in the sample, and the rest is transmitted to the detector for a readout. Using the spectrophotometer, the student found the λmax (the wavelength of light in nanometers (nm) that the pigment absorbs most intensely, for each sample) and recorded the results in Table 1. Table 1 also shows the transmittance and absorbance values at λmax. Transmittance, T, is defined as the fraction of light, expressed as a decimal, which passes through the sample. Absorbance, A, is given by:

A = –log(T) or 10–A = T

Spectrophotometer_table_1

Experiment 2:

A student is given a leaf from an unknown source. She crushes and extracts the pigment according to the procedure in Experiment 1. Measuring the absorbance spectrum in the spectrophotometer produces the following readout, shown in Diagram 2.

Leaf_absorbance

Diagram 2

Which of the following leaves most likely have the same pigment in high quantities?

10

Current high levels of fossil fuel use, including coal-burning power plants and gasoline-powered automobiles, have helped contribute to the high concentrations of sulfur trioxide, SO3, found in the atmosphere. When sulfur trioxide and water interact, they can undergo the following chemical reaction to produce sulfuric acid, which is the main contributor to acid rain worldwide:

Acid rain showers are particularly common near coal-burning power plants and large cities. These showers are responsible for significant economic damage to sidewalks, roads, and buildings. Scientists interested in studying the effects of acid rain often use basic substances like calcium carbonate, the main component of limestone buildings, and expose them to varying volumes of acid rain to determine what volume of acid rain is necessary to begin to erode a building. A sample graph of one scientist’s experiment is replicated below:

Passage_ii_-_main_passage

Measuring acid and base levels is commonly done with a scale called pH, which uses the concentration of hydrogen ions to determine the acidity. Hydrogen ions are in a balance with hydroxide ions to give a scale with a range from 0 to 14. Values equal to or between 0 and 6.9 represent the acidic range where hydrogen ions predominate and values equal to or ranging from 7.1 and 14 represent the basic range where hydroxide ions predominate. Thus, the more hydrogen ions present, the more acidic the solution.

Scientists can tell when a titration (pH) experiment passes a certain pH using compounds called indicators. Indicators are usually colorless at pH levels below that of their specified color change. A table of indicators used by the above scientists and the pH at which they change colors is presented below.

Passage_ii_table

What is the pH of a solution containing calcium carbonate and sulfuric acid when 29 mL of sulfuric acid have been added?

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